Augustin-Jean Fresnel (10 May 1788 – 14 July 1827) was a French civil engineer and
physicist
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe.
Physicists generally are interested in the root or ultimate caus ...
whose research in
optics
Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultraviole ...
led to the almost unanimous acceptance of the
wave theory of light
In physics, physical optics, or wave optics, is the branch of optics that studies Interference (wave propagation), interference, diffraction, Polarization (waves), polarization, and other phenomena for which the ray approximation of geometric opti ...
, excluding any remnant of
Newton
Newton most commonly refers to:
* Isaac Newton (1642–1726/1727), English scientist
* Newton (unit), SI unit of force named after Isaac Newton
Newton may also refer to:
Arts and entertainment
* ''Newton'' (film), a 2017 Indian film
* Newton ( ...
's
corpuscular theory
In optics, the corpuscular theory of light states that light is made up of small discrete particles called " corpuscles" (little particles) which travel in a straight line with a finite velocity and possess impetus. This was based on an alternate ...
, from the late 1830s until the end of the 19th century. He is perhaps better known for inventing the
catadioptric
A catadioptric optical system is one where refraction and reflection are combined in an optical system, usually via lenses (dioptrics) and curved mirrors (catoptrics). Catadioptric combinations are used in focusing systems such as searchlights, he ...
(reflective/refractive)
Fresnel lens
A Fresnel lens ( ; ; or ) is a type of composite compact lens developed by the French physicist Augustin-Jean Fresnel (1788–1827) for use in lighthouses. It has been called "the invention that saved a million ships."
The design allows the c ...
and for pioneering the use of "stepped" lenses to extend the visibility of
lighthouse
A lighthouse is a tower, building, or other type of physical structure designed to emit light from a system of lamps and lenses and to serve as a beacon for navigational aid, for maritime pilots at sea or on inland waterways.
Lighthouses mar ...
s, saving countless lives at sea. The simpler
dioptric
Dioptrics is the branch of optics dealing with refraction, similarly the branch dealing with mirror
A mirror or looking glass is an object that Reflection (physics), reflects an image. Light that bounces off a mirror will show an image of ...
(purely refractive) stepped lens, first proposed by
Count Buffon
Georges-Louis Leclerc, Comte de Buffon (; 7 September 1707 – 16 April 1788) was a French naturalist, mathematician, cosmologist, and encyclopédiste.
His works influenced the next two generations of naturalists, including two prominent Fr ...
and independently reinvented by Fresnel, is used in screen
magnifiers and in condenser lenses for
overhead projector
An overhead projector (often abbreviated to OHP), like a film or slide projector, uses light to project an enlarged image on a screen, allowing the view of a small document or picture to be shared with a large audience.
In the overhead project ...
s.
By expressing
Huygens's principle of secondary waves and
Young
Young may refer to:
* Offspring, the product of reproduction of a new organism produced by one or more parents
* Youth, the time of life when one is young, often meaning the time between childhood and adulthood
Music
* The Young, an American roc ...
's principle of
interference
Interference is the act of interfering, invading, or poaching. Interference may also refer to:
Communications
* Interference (communication), anything which alters, modifies, or disrupts a message
* Adjacent-channel interference, caused by extr ...
in quantitative terms, and supposing that simple colors consist of
sinusoidal
A sine wave, sinusoidal wave, or just sinusoid is a mathematical curve defined in terms of the '' sine'' trigonometric function, of which it is the graph. It is a type of continuous wave and also a smooth periodic function. It occurs often in m ...
waves, Fresnel gave the first satisfactory explanation of
diffraction
Diffraction is defined as the interference or bending of waves around the corners of an obstacle or through an aperture into the region of geometrical shadow of the obstacle/aperture. The diffracting object or aperture effectively becomes a s ...
by straight edges, including the first satisfactory wave-based explanation of rectilinear propagation. Part of his argument was a proof that the addition of sinusoidal functions of the same frequency but different
phases is analogous to the addition of forces with different directions. By further supposing that light waves are purely
transverse
Transverse may refer to:
*Transverse engine, an engine in which the crankshaft is oriented side-to-side relative to the wheels of the vehicle
*Transverse flute, a flute that is held horizontally
* Transverse force (or ''Euler force''), the tangen ...
, Fresnel explained the nature of
polarization, the mechanism of chromatic polarization, and the
transmission
Transmission may refer to:
Medicine, science and technology
* Power transmission
** Electric power transmission
** Propulsion transmission, technology allowing controlled application of power
*** Automatic transmission
*** Manual transmission
*** ...
and
reflection coefficient
In physics and electrical engineering the reflection coefficient is a parameter that describes how much of a wave is reflected by an impedance discontinuity in the transmission medium. It is equal to the ratio of the amplitude of the reflected wa ...
s at the interface between two transparent
isotropic
Isotropy is uniformity in all orientations; it is derived . Precise definitions depend on the subject area. Exceptions, or inequalities, are frequently indicated by the prefix ' or ', hence ''anisotropy''. ''Anisotropy'' is also used to describe ...
media. Then, by generalizing the direction-speed-polarization relation for
calcite
Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...
, he accounted for the directions and polarizations of the refracted rays in
doubly-refractive crystals of the ''biaxial'' class (those for which Huygens's secondary
wavefront
In physics, the wavefront of a time-varying ''wave field'' is the set (locus) of all points having the same ''phase''. The term is generally meaningful only for fields that, at each point, vary sinusoidally in time with a single temporal freque ...
s are not
axisymmetric). The period between the first publication of his pure-transverse-wave hypothesis, and the submission of his first correct solution to the biaxial problem, was less than a year.
Later, he coined the terms ''
linear polarization
In electrodynamics, linear polarization or plane polarization of electromagnetic radiation is a confinement of the electric field vector or magnetic field vector to a given plane along the direction of propagation. The term ''linear polarizati ...
'', ''
circular polarization
In electrodynamics, circular polarization of an electromagnetic wave is a polarization state in which, at each point, the electromagnetic field of the wave has a constant magnitude and is rotating at a constant rate in a plane perpendicular to t ...
'', and ''
elliptical polarization
In electrodynamics, elliptical polarization is the polarization of electromagnetic radiation such that the tip of the electric field vector describes an ellipse in any fixed plane intersecting, and normal to, the direction of propagation. An elli ...
'', explained how
optical rotation
Optical rotation, also known as polarization rotation or circular birefringence, is the rotation of the orientation of the plane of polarization about the optical axis of linearly polarized light as it travels through certain materials. Circul ...
could be understood as a difference in propagation speeds for the two directions of circular polarization, and (by allowing the reflection coefficient to be
complex
Complex commonly refers to:
* Complexity, the behaviour of a system whose components interact in multiple ways so possible interactions are difficult to describe
** Complex system, a system composed of many components which may interact with each ...
) accounted for the change in polarization due to
total internal reflection
Total internal reflection (TIR) is the optical phenomenon in which waves arriving at the interface (boundary) from one medium to another (e.g., from water to air) are not refracted into the second ("external") medium, but completely reflected b ...
, as exploited in the
Fresnel rhomb
A Fresnel rhomb is an optical prism that introduces a 90° phase difference between two perpendicular components of polarization, by means of two total internal reflections. If the incident beam is linearly polarized at 45° to the plane of inc ...
. Defenders of the established corpuscular theory could not match his quantitative explanations of so many phenomena on so few assumptions.
Fresnel had a lifelong battle with
tuberculosis
Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in ...
, to which he succumbed at the age of 39. Although he did not become a public celebrity in his lifetime, he lived just long enough to receive due recognition from his peers, including (on his deathbed) the
Rumford Medal
The Rumford Medal is an award bestowed by Britain's Royal Society every alternating year for "an outstandingly important recent discovery in the field of thermal or optical properties of matter made by a scientist working in Europe".
First awar ...
of the
Royal Society of London
The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...
, and his name is ubiquitous in the modern terminology of optics and waves. After the wave theory of light was subsumed by
Maxwell's
electromagnetic
In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions of a ...
theory in the 1860s, some attention was diverted from the magnitude of Fresnel's contribution. In the period between Fresnel's unification of physical optics and Maxwell's wider unification, a contemporary authority,
Humphrey Lloyd, described Fresnel's transverse-wave theory as "the noblest fabric which has ever adorned the domain of physical science, Newton's system of the universe alone excepted."
Early life
Family
Augustin-Jean Fresnel (also called Augustin Jean or simply Augustin), born in
Broglie,
Normandy
Normandy (; french: link=no, Normandie ; nrf, Normaundie, Nouormandie ; from Old French , plural of ''Normant'', originally from the word for "northman" in several Scandinavian languages) is a geographical and cultural region in Northwestern ...
, on 10 May 1788, was the second of four sons of the architect Jacques Fresnel (1755–1805) and his wife Augustine, ''née'' Mérimée (1755–1833). In 1790, following the
Revolution
In political science, a revolution (Latin: ''revolutio'', "a turn around") is a fundamental and relatively sudden change in political power and political organization which occurs when the population revolts against the government, typically due ...
, Broglie became part of the
département
In the administrative divisions of France, the department (french: département, ) is one of the three levels of government under the national level ("territorial collectivity, territorial collectivities"), between the regions of France, admin ...
of
Eure
Eure () is a department in Normandy in Northwestern France, named after the river Eure. Its prefecture is Évreux. In 2019, Eure had a population of 599,507.[Cherbourg
Cherbourg (; , , ), nrf, Chèrbourg, ) is a former commune and subprefecture located at the northern end of the Cotentin peninsula in the northwestern French department of Manche. It was merged into the commune of Cherbourg-Octeville on 28 Feb ...]
, and in 1794
[Silliman, 2008, p. 166.] to Jacques's home town of
Mathieu
Mathieu is both a surname and a given name. Notable people with the name include:
Surname
* André Mathieu (1929–1968), Canadian pianist and composer
* Anselme Mathieu (1828–1895), French Provençal poet
* Claude-Louis Mathieu (1783–187 ...
, where Madame Fresnel would spend 25 years as a widow, outliving two of her sons.
The first son, Louis (1786–1809), was admitted to the
École Polytechnique
École may refer to:
* an elementary school in the French educational stages normally followed by secondary education establishments (collège and lycée)
* École (river), a tributary of the Seine flowing in région Île-de-France
* École, Savoi ...
, became a lieutenant in the artillery, and was killed in action at
Jaca
Jaca (; in Aragonese: ''Chaca'' or ''Xaca'') is a city of northeastern Spain in the province of Huesca, located near the Pyrenees and the border with France. Jaca is an ancient fort on the Aragón River, situated at the crossing of two great ea ...
,
Spain
, image_flag = Bandera de España.svg
, image_coat = Escudo de España (mazonado).svg
, national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond")
, national_anthem = (English: "Royal March")
, i ...
, the day before his 23rd birthday. The third, Léonor (1790–1869), followed Augustin into civil
engineer
Engineers, as practitioners of engineering, are professionals who invent, design, analyze, build and test machines, complex systems, structures, gadgets and materials to fulfill functional objectives and requirements while considering the l ...
ing, succeeded him as secretary of the Lighthouse Commission, and helped to edit his collected works. The fourth,
Fulgence Fresnel
Fulgence Fresnel ( or ; ; (15 April 1795 – 30 November 1855) was a French Orientalist. He was brother to the noted physicist Augustin Fresnel (1788–1827). Fresnel was an Orientalist scholar who led one of the first archaeological teams t ...
(1795–1855), became a noted linguist, diplomat, and orientalist, and occasionally assisted Augustin with negotiations.
Fulgence died in Bagdad in 1855 having led a mission to explore Babylon.
Léonor apparently was the only one of the four who married.
Their mother's younger brother,
Jean François "Léonor" Mérimée (1757–1836), father of the writer
Prosper Mérimée
Prosper Mérimée (; 28 September 1803 – 23 September 1870) was a French writer in the movement of Romanticism, and one of the pioneers of the novella, a short novel or long short story. He was also a noted archaeologist and historian, and a ...
(1803–1870), was a
paint artist who turned his attention to the
chemistry
Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions ...
of painting. He became the Permanent Secretary of the
École des Beaux-Arts
École des Beaux-Arts (; ) refers to a number of influential art schools in France. The term is associated with the Beaux-Arts style in architecture and city planning that thrived in France and other countries during the late nineteenth century ...
and (until 1814) a professor at the École Polytechnique, and was the initial point of contact between Augustin and the leading optical physicists of the day .
Education
The Fresnel brothers were initially home-schooled by their mother. The sickly Augustin was considered the slow one, not inclined to memorization; but the popular story that he hardly began to read until the age of eight is disputed. At the age of nine or ten he was undistinguished except for his ability to turn tree-branches into toy bows and guns that worked far too well, earning himself the title ''l'homme de génie'' (the man of genius) from his accomplices, and a united crackdown from their elders.
In 1801, Augustin was sent to the ''École Centrale'' at
Caen
Caen (, ; nrf, Kaem) is a commune in northwestern France. It is the prefecture of the department of Calvados. The city proper has 105,512 inhabitants (), while its functional urban area has 470,000,[Adrien-Marie Legendre
Adrien-Marie Legendre (; ; 18 September 1752 – 9 January 1833) was a French mathematician who made numerous contributions to mathematics. Well-known and important concepts such as the Legendre polynomials and Legendre transformation are named ...]
. Graduating in 1806, he then enrolled at the
École Nationale des Ponts et Chaussées
École may refer to:
* an elementary school in the French educational stages normally followed by secondary education establishments (collège and lycée)
* École (river), a tributary of the Seine flowing in région Île-de-France
* École, Savoi ...
(National School of Bridges and Roads, also known as "ENPC" or "École des Ponts"), from which he graduated in 1809, entering the service of the
Corps des Ponts et Chaussées
The ''Corps des ponts, des eaux et des forêts'' (in English "Corps of Bridges, Waters and Forests") is a technical Grand Corps of the French State (grand corps de l'Etat). Its members are senior officials, mainly employed by the French Ministry of ...
as an ''ingénieur ordinaire aspirant'' (ordinary engineer in training). Directly or indirectly, he was to remain in the employment of the "Corps des Ponts" for the rest of his life.
Religious formation
Fresnel's parents were
Roman Catholics
The Catholic Church, also known as the Roman Catholic Church, is the largest Christian church, with 1.3 billion baptized Catholics worldwide . It is among the world's oldest and largest international institutions, and has played a ...
of the
Jansenist
Jansenism was an early modern theological movement within Catholicism, primarily active in the Kingdom of France, that emphasized original sin, human depravity, the necessity of divine grace, and predestination. It was declared a heresy by th ...
sect, characterized by an extreme
Augustinian Augustinian may refer to:
*Augustinians, members of religious orders following the Rule of St Augustine
*Augustinianism, the teachings of Augustine of Hippo and his intellectual heirs
*Someone who follows Augustine of Hippo
* Canons Regular of Sain ...
view of
original sin
Original sin is the Christian doctrine that holds that humans, through the fact of birth, inherit a tainted nature in need of regeneration and a proclivity to sinful conduct. The biblical basis for the belief is generally found in Genesis 3 (t ...
. Religion took first place in the boys' home-schooling. In 1802, his mother said:
Augustin remained a Jansenist. He regarded his intellectual talents as gifts from God, and considered it his duty to use them for the benefit of others. According to his fellow engineer Alphonse Duleau, who helped to nurse him through his final illness, Fresnel saw the study of nature as part of the study of the power and goodness of God. He placed virtue above science and genius. In his last days he prayed for "strength of soul," not against death alone, but against "the interruption of discoveries… of which he hoped to derive useful applications."
Jansenism is considered
heretical
Heresy is any belief or theory that is strongly at variance with established beliefs or customs, in particular the accepted beliefs of a church or religious organization. The term is usually used in reference to violations of important religi ...
by the Roman Catholic Church, and Grattan-Guinness suggests this is why Fresnel never gained a permanent academic teaching post; his only teaching appointment was at the
Athénée in the winter of 1819–20. The article on Fresnel in the ''
Catholic Encyclopedia
The ''Catholic Encyclopedia: An International Work of Reference on the Constitution, Doctrine, Discipline, and History of the Catholic Church'' (also referred to as the ''Old Catholic Encyclopedia'' and the ''Original Catholic Encyclopedia'') i ...
'' does not mention his Jansenism, but describes him as "a deeply religious man and remarkable for his keen sense of duty."
Engineering assignments
Fresnel was initially posted to the western département of
Vendée
Vendée (; br, Vande) is a department in the Pays de la Loire region in Western France, on the Atlantic coast. In 2019, it had a population of 685,442. . There, in 1811, he anticipated what became known as the
Solvay process
The Solvay process or ammonia-soda process is the major industrial process for the production of sodium carbonate (soda ash, Na2CO3). The ammonia-soda process was developed into its modern form by the Belgian chemist Ernest Solvay during the 1860s. ...
for producing
soda ash, except that recycling of the
ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous was ...
was not considered. That difference may explain why leading chemists, who learned of his discovery through his uncle Léonor, eventually thought it uneconomic.
![028_album_dauphiné,_Nyons,_Drome,_by_AD_cropped](https://upload.wikimedia.org/wikipedia/commons/3/39/028_album_dauphin%C3%A9%2C_Nyons%2C_Drome%2C_by_AD_cropped.jpg)
About 1812, Fresnel was sent to
Nyons
Nyons (; See mistralian norm, and classical norm of Provençal.) is a commune in the Drôme department in southeastern France.
History
Nyons was settled in the 6th century BC as ''Nyrax'' by a Gallic tribe, probably the Segusiavi or the Sequ ...
, in the southern département of
Drôme
Drôme (; Occitan: ''Droma''; Arpitan: ''Drôma'') is the southernmost department in the Auvergne-Rhône-Alpes region of Southeastern France. Named after the river Drôme, it had a population of 516,762 as of 2019. , to assist with the imperial highway that was to connect Spain and Italy.
It is from Nyons that we have the first evidence of his interest in optics. On 15 May 1814, while work was slack due to
Napoleon
Napoleon Bonaparte ; it, Napoleone Bonaparte, ; co, Napulione Buonaparte. (born Napoleone Buonaparte; 15 August 1769 – 5 May 1821), later known by his regnal name Napoleon I, was a French military commander and political leader who ...
's defeat, Fresnel wrote a "''P.S.''" to his brother Léonor, saying in part:
As late as 28 December he was still waiting for information, but he had received Biot's memoir by 10 February 1815. (The ''
Institut de France
The (; ) is a French learned society, grouping five , including the Académie Française. It was established in 1795 at the direction of the National Convention. Located on the Quai de Conti in the 6th arrondissement of Paris, the institute m ...
'' had taken over the functions of the French ''
Académie des Sciences
The French Academy of Sciences (French: ''Académie des sciences'') is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French scientific research. It was at the ...
'' and other ''académies'' in 1795. In 1816 the ''Académie des Sciences'' regained its name and autonomy, but remained part of the institute.)
In March 1815, perceiving Napoleon's return from
Elba
Elba ( it, isola d'Elba, ; la, Ilva) is a Mediterranean island in Tuscany, Italy, from the coastal town of Piombino on the Italian mainland, and the largest island of the Tuscan Archipelago. It is also part of the Arcipelago Toscano National ...
as "an attack on civilization", Fresnel departed without leave, hastened to
Toulouse
Toulouse ( , ; oc, Tolosa ) is the prefecture of the French department of Haute-Garonne and of the larger region of Occitania. The city is on the banks of the River Garonne, from the Mediterranean Sea, from the Atlantic Ocean and from Par ...
and offered his services to the royalist resistance, but soon found himself on the sick list. Returning to Nyons in defeat, he was threatened and had his windows broken. During the
Hundred Days
The Hundred Days (french: les Cent-Jours ), also known as the War of the Seventh Coalition, marked the period between Napoleon's return from eleven months of exile on the island of Elba to Paris on20 March 1815 and the second restoration ...
he was placed on suspension, which he was eventually allowed to spend at his mother's house in Mathieu. There he used his enforced leisure to begin his optical experiments.
Contributions to physical optics
Historical context: From Newton to Biot
The appreciation of Fresnel's reconstruction of physical optics might be assisted by an overview of the fragmented state in which he found the subject. In this subsection, optical phenomena that were unexplained or whose explanations were disputed are named in
bold type.
![Refraction - Huygens-Fresnel principle](https://upload.wikimedia.org/wikipedia/commons/b/b7/Refraction_-_Huygens-Fresnel_principle.svg)
The
corpuscular theory of light
In optics, the corpuscular theory of light states that light is made up of small discrete particles called " corpuscles" (little particles) which travel in a straight line with a finite velocity and possess impetus. This was based on an alternate ...
, favored by
Isaac Newton
Sir Isaac Newton (25 December 1642 – 20 March 1726/27) was an English mathematician, physicist, astronomer, alchemist, theologian, and author (described in his time as a "natural philosopher"), widely recognised as one of the grea ...
and accepted by nearly all of Fresnel's seniors, easily explained
rectilinear propagation
Rectilinear propagation describes the tendency of electromagnetic waves (light) to travel in a straight line. Light does not deviate when travelling through a homogeneous medium, which has the same refractive index throughout; otherwise, light suf ...
: the corpuscles obviously moved very fast, so that their paths were very nearly straight. The
wave theory, as developed by
Christiaan Huygens
Christiaan Huygens, Lord of Zeelhem, ( , , ; also spelled Huyghens; la, Hugenius; 14 April 1629 – 8 July 1695) was a Dutch mathematician, physicist, engineer, astronomer, and inventor, who is regarded as one of the greatest scientists of ...
in his ''
Treatise on Light
''Treatise on Light: In Which Are Explained the Causes of That Which Occurs in Reflection & Refraction'' (french: Traité de la Lumière'': Où Sont Expliquées les Causes de ce qui Luy Arrive Dans la Reflexion & Dans la Refraction'') is a book ...
'' (1690), explained rectilinear propagation on the assumption that each point crossed by a traveling wavefront becomes the source of a secondary wavefront. Given the initial position of a traveling wavefront, any later position (according to Huygens) was the common
tangent
In geometry, the tangent line (or simply tangent) to a plane curve at a given point is the straight line that "just touches" the curve at that point. Leibniz defined it as the line through a pair of infinitely close points on the curve. More ...
surface (
envelope
An envelope is a common packaging item, usually made of thin, flat material. It is designed to contain a flat object, such as a letter or card.
Traditional envelopes are made from sheets of paper cut to one of three shapes: a rhombus, a shor ...
) of the secondary wavefronts emitted from the earlier position. As the extent of the common tangent was limited by the extent of the initial wavefront, the repeated application of Huygens's construction to a plane wavefront of limited extent (in a uniform medium) gave a straight, parallel beam. While this construction indeed predicted rectilinear propagation, it was difficult to reconcile with the common observation that wavefronts on the surface of water can bend around obstructions, and with the similar behavior of
sound
In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid.
In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' by the ...
waves – causing Newton to maintain, to the end of his life, that if light consisted of waves it would "bend and spread every way" into the shadows.
Huygens's theory neatly explained the law of
ordinary reflection and the law of
ordinary refraction ("Snell's law"), provided that the secondary waves traveled slower in denser media (those of higher
refractive index
In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium.
The refractive index determines how much the path of light is bent, or ...
). The corpuscular theory, with the hypothesis that the corpuscles were subject to forces acting perpendicular to surfaces, explained the same laws equally well, albeit with the implication that light traveled ''faster'' in denser media; that implication was wrong, but could not be directly disproven with the technology of Newton's time or even Fresnel's time .
Similarly inconclusive was
stellar aberration
In astronomy, aberration (also referred to as astronomical aberration, stellar aberration, or velocity aberration) is a phenomenon which produces an apparent motion of celestial objects about their true positions, dependent on the velocity of t ...
—that is, the apparent change in the position of a star due to the velocity of the earth across the line of sight (not to be confused with
stellar parallax
Stellar parallax is the apparent shift of position of any nearby star (or other object) against the background of distant objects, and a basis for determining (through trigonometry) the distance of the object. Created by the different orbital p ...
, which is due to the ''displacement'' of the earth across the line of sight). Identified by
James Bradley
James Bradley (1692–1762) was an English astronomer and priest who served as the third Astronomer Royal from 1742. He is best known for two fundamental discoveries in astronomy, the aberration of light (1725–1728), and the nutation of the ...
in 1728, stellar aberration was widely taken as confirmation of the corpuscular theory. But it was equally compatible with the wave theory, as
Euler
Leonhard Euler ( , ; 15 April 170718 September 1783) was a Swiss mathematician, physicist, astronomer, geographer, logician and engineer who founded the studies of graph theory and topology and made pioneering and influential discoveries in ma ...
noted in 1746 – tacitly assuming that the
aether (the supposed wave-bearing medium) near the earth was not disturbed by the motion of the earth.
The outstanding strength of Huygens's theory was his explanation of the
birefringence
Birefringence is the optical property of a material having a refractive index that depends on the polarization and propagation direction of light. These optically anisotropic materials are said to be birefringent (or birefractive). The birefring ...
(double refraction) of "
Iceland crystal" (transparent
calcite
Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...
), on the assumption that the secondary waves are spherical for the ordinary refraction (which satisfies Snell's law) and
spheroid
A spheroid, also known as an ellipsoid of revolution or rotational ellipsoid, is a quadric surface obtained by rotating an ellipse about one of its principal axes; in other words, an ellipsoid with two equal semi-diameters. A spheroid has cir ...
al for the ''extraordinary'' refraction (which does not). In general, Huygens's common-tangent construction implies that rays are ''paths of least time'' between successive positions of the wavefront, in accordance with
Fermat's principle
Fermat's principle, also known as the principle of least time, is the link between ray optics and wave optics. In its original "strong" form, Fermat's principle states that the path taken by a ray between two given points is the pat ...
. In the special case of
isotropic
Isotropy is uniformity in all orientations; it is derived . Precise definitions depend on the subject area. Exceptions, or inequalities, are frequently indicated by the prefix ' or ', hence ''anisotropy''. ''Anisotropy'' is also used to describe ...
media, the secondary wavefronts must be spherical, and Huygens's construction then implies that the rays are perpendicular to the wavefront; indeed, the law of ''ordinary'' refraction can be separately derived from that premise, as
Ignace-Gaston Pardies did before Huygens.
![Ggb in soap bubble 3](https://upload.wikimedia.org/wikipedia/commons/3/34/Ggb_in_soap_bubble_3.JPG)
Although Newton rejected the wave theory, he noticed its potential to explain colors, including the colors of "
thin plates" (e.g., "
Newton's rings
Newton's rings is a phenomenon in which an interference pattern is created by the reflection of light between two surfaces, typically a spherical surface and an adjacent touching flat surface. It is named after Isaac Newton, who investigated the ...
", and the colors of skylight reflected in soap bubbles), on the assumption that light consists of ''periodic'' waves, with the lowest
frequencies
Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is eq ...
(longest
wavelength
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats.
It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tro ...
s) at the red end of the spectrum, and the highest frequencies (shortest wavelengths) at the violet end. In 1672 he published a heavy hint to that effect, but contemporary supporters of the wave theory failed to act on it:
Robert Hooke
Robert Hooke FRS (; 18 July 16353 March 1703) was an English polymath active as a scientist, natural philosopher and architect, who is credited to be one of two scientists to discover microorganisms in 1665 using a compound microscope that ...
treated light as a periodic sequence of pulses but did not use frequency as the criterion of color, while Huygens treated the waves as individual pulses without any periodicity; and Pardies died young in 1673. Newton himself tried to explain colors of thin plates using the corpuscular theory, by supposing that his corpuscles had the wavelike property of alternating between "fits of easy transmission" and "fits of easy reflection", the distance between like "fits" depending on the color and the medium and, awkwardly, on the angle of refraction or reflection into that medium. More awkwardly still, this theory required thin plates to reflect only at the back surface, although ''thick'' plates manifestly reflected also at the front surface. It was not until 1801 that
Thomas Young, in the
Bakerian Lecture
The Bakerian Medal is one of the premier medals of the Royal Society that recognizes exceptional and outstanding science. It comes with a medal award and a prize lecture. The medalist is required to give a lecture on any topic related to physical ...
for that year, cited Newton's hint, and accounted for the colors of a thin plate as the combined effect of the front and back reflections, which reinforce or cancel each other according to the ''wavelength'' and the thickness. Young similarly explained the colors of "striated surfaces" (e.g.,
gratings) as the wavelength-dependent reinforcement or cancellation of reflections from adjacent lines. He described this reinforcement or cancellation as
interference
Interference is the act of interfering, invading, or poaching. Interference may also refer to:
Communications
* Interference (communication), anything which alters, modifies, or disrupts a message
* Adjacent-channel interference, caused by extr ...
.
![Thomas Young (scientist)](https://upload.wikimedia.org/wikipedia/commons/9/9f/Thomas_Young_%28scientist%29.jpg)
Neither Newton nor Huygens satisfactorily explained
diffraction
Diffraction is defined as the interference or bending of waves around the corners of an obstacle or through an aperture into the region of geometrical shadow of the obstacle/aperture. The diffracting object or aperture effectively becomes a s ...
—the blurring and fringing of shadows where, according to rectilinear propagation, they ought to be sharp. Newton, who called diffraction "inflexion", supposed that rays of light passing close to obstacles were bent ("inflected"); but his explanation was only qualitative. Huygens's common-tangent construction, without modifications, could not accommodate diffraction at all. Two such modifications were proposed by Young in the same 1801 Bakerian Lecture: first, that the secondary waves near the edge of an obstacle could diverge into the shadow, but only weakly, due to limited reinforcement from other secondary waves; and second, that diffraction by an edge was caused by interference between two rays: one reflected off the edge, and the other inflected while passing near the edge. The latter ray would be undeviated if sufficiently far from the edge, but Young did not elaborate on that case. These were the earliest suggestions that the degree of diffraction depends on wavelength. Later, in the 1803 Bakerian Lecture, Young ceased to regard inflection as a separate phenomenon, and produced evidence that diffraction fringes ''inside'' the shadow of a narrow obstacle were due to interference: when the light from one side was blocked, the internal fringes disappeared. But Young was alone in such efforts until Fresnel entered the field.
Huygens, in his investigation of double refraction, noticed something that he could not explain: when light passes through two similarly oriented calcite crystals at normal incidence, the ordinary ray emerging from the first crystal suffers only the ordinary refraction in the second, while the extraordinary ray emerging from the first suffers only the extraordinary refraction in the second; but when the second crystal is rotated 90° about the incident rays, the roles are interchanged, so that the ordinary ray emerging from the first crystal suffers only the extraordinary refraction in the second, and vice versa. This discovery gave Newton another reason to reject the wave theory: rays of light evidently had "sides". Corpuscles could have sides (or ''poles'', as they would later be called); but waves of light could not, because (so it seemed) any such waves would need to be
longitudinal
Longitudinal is a geometric term of location which may refer to:
* Longitude
** Line of longitude, also called a meridian
* Longitudinal engine, an internal combustion engine in which the crankshaft is oriented along the long axis of the vehicle, ...
(with vibrations in the direction of propagation). Newton offered an alternative "Rule" for the extraordinary refraction, which rode on his authority through the 18th century, although he made "no known attempt to deduce it from any principles of optics, corpuscular or otherwise."
![Etienne-Louis Malus](https://upload.wikimedia.org/wikipedia/commons/7/79/Etienne-Louis_Malus.jpg)
In 1808, the extraordinary refraction of calcite was investigated experimentally, with unprecedented accuracy, by
Étienne-Louis Malus
Étienne-Louis Malus (; ; 23 July 1775 – 23 February 1812) was a French officer, engineer, physicist, and mathematician.
Malus was born in Paris, France. He participated in Napoleon's expedition into Egypt (1798 to 1801) and was a member o ...
, and found to be consistent with Huygens's spheroid construction, not Newton's "Rule". Malus, encouraged by
Pierre-Simon Laplace
Pierre-Simon, marquis de Laplace (; ; 23 March 1749 – 5 March 1827) was a French scholar and polymath whose work was important to the development of engineering, mathematics, statistics, physics, astronomy, and philosophy. He summarized ...
, then sought to explain this law in corpuscular terms: from the known relation between the incident and refracted ray directions, Malus derived the corpuscular velocity (as a function of direction) that would satisfy
Maupertuis
Pierre Louis Moreau de Maupertuis (; ; 1698 – 27 July 1759) was a French mathematician, philosopher and man of letters. He became the Director of the Académie des Sciences, and the first President of the Prussian Academy of Science, at the ...
's "least action" principle. But, as Young pointed out, the existence of such a velocity law was guaranteed by Huygens's spheroid, because Huygens's construction leads to Fermat's principle, which becomes Maupertuis's principle if the ray speed is replaced by the reciprocal of the particle speed! The corpuscularists had not found a ''force'' law that would yield the alleged velocity law, except by a circular argument in which a force acting at the ''surface'' of the crystal inexplicably depended on the direction of the (possibly subsequent) velocity ''within'' the crystal. Worse, it was doubtful that any such force would satisfy the conditions of Maupertuis's principle. In contrast, Young proceeded to show that "a medium more easily compressible in one direction than in any direction perpendicular to it, as if it consisted of an infinite number of parallel plates connected by a substance somewhat less elastic" admits spheroidal longitudinal wavefronts, as Huygens supposed.
![Calcite and polarizing filter](https://upload.wikimedia.org/wikipedia/commons/f/f3/Calcite_and_polarizing_filter.gif)
But Malus, in the midst of his experiments on double refraction, noticed something else: when a ray of light is reflected off a non-metallic surface at the appropriate angle, it behaves like ''one'' of the two rays emerging from a calcite crystal. It was Malus who coined the term
polarization to describe this behavior, although the polarizing angle became known as
Brewster's angle
Brewster's angle (also known as the polarization angle) is an angle of incidence at which light with a particular polarization is perfectly transmitted through a transparent dielectric surface, with ''no reflection''. When ''unpolarized'' light ...
after its dependence on the refractive index was determined experimentally by
David Brewster
Sir David Brewster KH PRSE FRS FSA Scot FSSA MICE (11 December 178110 February 1868) was a British scientist, inventor, author, and academic administrator. In science he is principally remembered for his experimental work in physical optics ...
in 1815. Malus also introduced the term ''
plane of polarization
The term ''plane of polarization'' refers to the direction of polarization of '' linearly-polarized'' light or other electromagnetic radiation. Unfortunately the term is used with two contradictory meanings. As originally defined by Étienne-Lou ...
''. In the case of polarization by reflection, his "plane of polarization" was the plane of the incident and reflected rays; in modern terms, this is the plane ''normal'' to the ''electric'' vibration. In 1809, Malus further discovered that the intensity of light passing through ''two'' polarizers is proportional to the squared cosine of the angle between their planes of polarization (
Malus's law
A polarizer or polariser is an optical filter that lets light waves of a specific polarization pass through while blocking light waves of other polarizations. It can filter a beam of light of undefined or mixed polarization into a beam of well ...
), whether the polarizers work by reflection or double refraction, and that ''all'' birefringent crystals produce both extraordinary refraction and polarization. As the corpuscularists started trying to explain these things in terms of polar "molecules" of light, the wave-theorists had ''no working hypothesis'' on the nature of polarization, prompting Young to remark that Malus's observations "present greater difficulties to the advocates of the undulatory theory than any other facts with which we are acquainted."
Malus died in February 1812, at the age of 36, shortly after receiving the
Rumford Medal
The Rumford Medal is an award bestowed by Britain's Royal Society every alternating year for "an outstandingly important recent discovery in the field of thermal or optical properties of matter made by a scientist working in Europe".
First awar ...
for his work on polarization.
In August 1811,
François Arago
Dominique François Jean Arago ( ca, Domènec Francesc Joan Aragó), known simply as François Arago (; Catalan: ''Francesc Aragó'', ; 26 February 17862 October 1853), was a French mathematician, physicist, astronomer, freemason, supporter of t ...
reported that if a thin plate of
mica
Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into extremely thin elastic plates. This characteristic is described as perfect basal cleavage. Mica is ...
was viewed against a white polarized backlight through a calcite crystal, the two images of the mica were of
complementary colors
Complementary colors are pairs of colors which, when combined or mixed, cancel each other out (lose hue) by producing a grayscale color like white or black. When placed next to each other, they create the strongest contrast for those two co ...
(the overlap having the same color as the background). The light emerging from the mica was "''de''polarized" in the sense that there was no orientation of the calcite that made one image disappear; yet it was not ordinary ("''un''polarized") light, for which the two images would be of the same color. Rotating the calcite around the line of sight changed the colors, though they remained complementary. Rotating the mica changed the ''saturation'' (not the hue) of the colors. This phenomenon became known as chromatic polarization. Replacing the mica with a much thicker plate of
quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical form ...
, with its faces perpendicular to the optic axis (the axis of Huygens's spheroid or Malus's velocity function), produced a similar effect, except that rotating the quartz made no difference. Arago tried to explain his observations in ''corpuscular'' terms.
![Arago Francois portrait](https://upload.wikimedia.org/wikipedia/commons/b/b1/Arago_Francois_portrait.jpg)
In 1812, as Arago pursued further qualitative experiments and other commitments,
Jean-Baptiste Biot
Jean-Baptiste Biot (; ; 21 April 1774 – 3 February 1862) was a French physicist, astronomer, and mathematician who co-discovered the Biot–Savart law of magnetostatics with Félix Savart, established the reality of meteorites, made an early ba ...
reworked the same ground using a
gypsum
Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywall. ...
lamina in place of the mica, and found empirical formulae for the intensities of the ordinary and extraordinary images. The formulae contained two coefficients, supposedly representing colors of rays "affected" and "unaffected" by the plate – the "affected" rays being of the same color mix as those reflected by amorphous thin plates of proportional, but lesser, thickness.
![T1- d642 - Fig](https://upload.wikimedia.org/wikipedia/commons/7/72/T1-_d642_-_Fig._327._%E2%80%94_J._B._Biot.png)
Arago protested, declaring that he had made some of the same discoveries but had not had time to write them up. In fact the overlap between Arago's work and Biot's was minimal, Arago's being only qualitative and wider in scope (attempting to include polarization by reflection). But the dispute triggered a notorious falling-out between the two men.
Later that year, Biot tried to explain the observations as an oscillation of the alignment of the "affected" corpuscles at a frequency proportional to that of Newton's "fits", due to forces depending on the alignment. This theory became known as ''mobile polarization''. To reconcile his results with a sinusoidal oscillation, Biot had to suppose that the corpuscles emerged with one of two permitted orientations, namely the extremes of the oscillation, with probabilities depending on the
phase
Phase or phases may refer to:
Science
*State of matter, or phase, one of the distinct forms in which matter can exist
*Phase (matter), a region of space throughout which all physical properties are essentially uniform
* Phase space, a mathematic ...
of the oscillation. Corpuscular optics was becoming expensive on assumptions. But in 1813, Biot reported that the case of quartz was simpler: the observable phenomenon (now called
optical rotation
Optical rotation, also known as polarization rotation or circular birefringence, is the rotation of the orientation of the plane of polarization about the optical axis of linearly polarized light as it travels through certain materials. Circul ...
or ''optical activity'' or sometimes ''rotary polarization'') was a gradual rotation of the polarization direction with distance, and could be explained by a corresponding rotation (''not'' oscillation) of the corpuscles.
Early in 1814, reviewing Biot's work on chromatic polarization, Young noted that the periodicity of the color as a function of the plate thickness – including the factor by which the period exceeded that for a reflective thin plate, and even the effect of obliquity of the plate (but not the role of polarization)—could be explained by the wave theory in terms of the different propagation times of the ordinary and extraordinary waves through the plate. But Young was then the only public defender of the wave theory.
[Frankel, 1976, p. 176; cf. Silliman, 1967, pp. 142–3.]
In summary, in the spring of 1814, as Fresnel tried in vain to guess what polarization was, the corpuscularists thought that they knew, while the wave-theorists (if we may use the plural) literally had no idea. Both theories claimed to explain rectilinear propagation, but the wave explanation was overwhelmingly regarded as unconvincing. The corpuscular theory could not rigorously link double refraction to surface forces; the wave theory could not yet link it to polarization. The corpuscular theory was weak on thin plates and silent on gratings;
[Newton (1730) observed feathers acting as reflection gratings and as a transmission gratings, but classified the former case under thin plates (p. 252), and the latter, more vaguely, under inflection (p. 322). In retrospect, the latter experiment (p. 322, end of Obs. 2) is dangerous to eyesight and should not be repeated as written.] the wave theory was strong on both, but under-appreciated. Concerning diffraction, the corpuscular theory did not yield quantitative predictions, while the wave theory had begun to do so by considering diffraction as a manifestation of interference, but had only considered two rays at a time. Only the corpuscular theory gave even a vague insight into Brewster's angle, Malus's law, or optical rotation. Concerning chromatic polarization, the wave theory explained the periodicity far better than the corpuscular theory, but had nothing to say about the role of polarization; and its explanation of the periodicity was largely ignored. And Arago had founded the study of chromatic polarization, only to lose the lead, controversially, to Biot. Such were the circumstances in which Arago first heard of Fresnel's interest in optics.
Rêveries
![Léonor Mérimée](https://upload.wikimedia.org/wikipedia/commons/5/5b/L%C3%A9onor_M%C3%A9rim%C3%A9e.jpg)
Fresnel's letters from later in 1814 reveal his interest in the wave theory, including his awareness that it explained the constancy of the speed of light and was at least compatible with stellar aberration. Eventually he compiled what he called his ''rêveries'' (musings) into an essay and submitted it via Léonor Mérimée to
André-Marie Ampère
André-Marie Ampère (, ; ; 20 January 177510 June 1836) was a French physicist and mathematician who was one of the founders of the science of classical electromagnetism, which he referred to as "electrodynamics". He is also the inventor of nu ...
, who did not respond directly. But on 19 December, Mérimée dined with Ampère and Arago, with whom he was acquainted through the École Polytechnique; and Arago promised to look at Fresnel's essay.
[The story that Ampère lost the essay (propagated from Boutry, 1948, p. 593?) is implicitly contradicted by Darrigol (2012, p. 198), Buchwald (1989, p. 117), Mérimée's letter to Fresnel dated 20 December 1814 (in Fresnel, 1866–70, vol. 2, pp. 830–31), and two footnotes in Fresnel's collected works (Fresnel, 1866–70, vol. 1, pp. xxix–xxx, note 4, and p. 6n).]
In mid 1815, on his way home to Mathieu to serve his suspension, Fresnel met Arago in
Paris
Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. S ...
and spoke of the wave theory and stellar aberration. He was informed that he was trying to break down open doors ("''il enfonçait des portes ouvertes''"), and directed to classical works on optics.
Diffraction
First attempt (1815)
On 12 July 1815, as Fresnel was about to leave Paris, Arago left him a note on a new topic:
Fresnel would not have ready access to these works outside Paris, and could not read English.
[Fresnel, 1866–70, vol. 1, pp. 6–7.] But, in Mathieu – with a point-source of light made by focusing sunlight with a drop of honey, a crude
micrometer Micrometer can mean:
* Micrometer (device), used for accurate measurements by means of a calibrated screw
* American spelling of micrometre
The micrometre ( international spelling as used by the International Bureau of Weights and Measures; ...
of his own construction, and supporting apparatus made by a local locksmith – he began his own experiments. His technique was novel: whereas earlier investigators had projected the fringes onto a screen, Fresnel soon abandoned the screen and observed the fringes in space, through a lens with the micrometer at its focus, allowing more accurate measurements while requiring less light.
Later in July, after Napoleon's final defeat, Fresnel was reinstated with the advantage of having backed the winning side. He requested a two-month leave of absence, which was readily granted because roadworks were in abeyance.
On 23 September he wrote to Arago, beginning "I think I have found the explanation and the law of colored fringes which one notices in the shadows of bodies illuminated by a luminous point." In the same paragraph, however, Fresnel implicitly acknowledged doubt about the novelty of his work: noting that he would need to incur some expense in order to improve his measurements, he wanted to know "whether this is not useless, and whether the law of diffraction has not already been established by sufficiently exact experiments." He explained that he had not yet had a chance to acquire the items on his reading lists,
with the apparent exception of "Young's book", which he could not understand without his brother's help.
["Young's book", which Fresnel distinguished from the ''Philosophical Transactions'', is presumably ''A Course of Lectures on Natural Philosophy and the Mechanical Arts'' (2 volumes, 1807). I]
vol. 1
the relevant illustrations are Plate (facing p. 777), including the famous two-source interference pattern (Fig. 267), and Plate (facing p. 787), including the hyperbolic paths of the fringes in that pattern (Fig. 442) followed by sketches of other diffraction patterns and thin-plate patterns, with no visual hints on their physical causes. I
vol. 2
which includes the Bakerian lectures from the ''Philosophical Transactions'', Fig. 108 (p. 632) shows just one case of an undeviated direct ray intersecting a reflected ray. Not surprisingly, he had retraced many of Young's steps.
In a memoir sent to the institute on 15 October 1815, Fresnel mapped the external and internal fringes in the shadow of a wire. He noticed, like Young before him, that the internal fringes disappeared when the light from one side was blocked, and concluded that "the vibrations of two rays that cross each other under a very small angle can contradict each other…" But, whereas Young took the disappearance of the internal fringes as ''confirmation'' of the principle of interference, Fresnel reported that it was the internal fringes that first drew his attention to the principle. To explain the diffraction pattern, Fresnel constructed the internal fringes by considering the intersections of circular wavefronts emitted from the two edges of the obstruction, and the external fringes by considering the intersections between direct waves and waves reflected off the nearer edge. For the external fringes, to obtain tolerable agreement with observation, he had to suppose that the reflected wave was
inverted; and he noted that the predicted paths of the fringes were hyperbolic. In the part of the memoir that most clearly surpassed Young, Fresnel explained the ordinary laws of reflection and refraction in terms of interference, noting that if two parallel rays were reflected or refracted at other than the prescribed angle, they would no longer have the same
phase
Phase or phases may refer to:
Science
*State of matter, or phase, one of the distinct forms in which matter can exist
*Phase (matter), a region of space throughout which all physical properties are essentially uniform
* Phase space, a mathematic ...
in a common perpendicular plane, and every vibration would be cancelled by a nearby vibration. He noted that his explanation was valid provided that the surface irregularities were much smaller than the wavelength.
On 10 November, Fresnel sent a supplementary note dealing with Newton's rings and with gratings, including, for the first time, ''transmission'' gratings – although in that case the interfering rays were still assumed to be "inflected", and the experimental verification was inadequate because it used only two threads.
As Fresnel was not a member of the institute, the fate of his memoir depended heavily on the report of a single member. The reporter for Fresnel's memoir turned out to be Arago (with
Poinsot as the other reviewer). On 8 November, Arago wrote to Fresnel:
Fresnel was troubled, wanting to know more precisely where he had collided with Young. Concerning the curved paths of the "colored bands", Young had noted the hyperbolic paths of the fringes in the
two-source interference pattern, corresponding roughly to Fresnel's ''internal'' fringes, and had described the hyperbolic fringes that appear ''on the screen'' within rectangular shadows. He had not mentioned the curved paths of the ''external'' fringes of a shadow; but, as he later explained, that was because Newton had already done so. Newton evidently thought the fringes were ''
caustics''. Thus Arago erred in his belief that the curved paths of the fringes were fundamentally incompatible with the corpuscular theory.
Arago's letter went on to request more data on the external fringes. Fresnel complied, until he exhausted his leave and was assigned to
Rennes
Rennes (; br, Roazhon ; Gallo: ''Resnn''; ) is a city in the east of Brittany in northwestern France at the confluence of the Ille and the Vilaine. Rennes is the prefecture of the region of Brittany, as well as the Ille-et-Vilaine department ...
in the département of
Ille-et-Vilaine
Ille-et-Vilaine (; br, Il-ha-Gwilen) is a department of France, located in the region of Brittany in the northwest of the country. It is named after the two rivers of the Ille and the Vilaine. It had a population of 1,079,498 in 2019. . At this point Arago interceded with
Gaspard de Prony
Baron Gaspard Clair François Marie Riche de Prony (22 July 1755 – 29 July 1839) was a French mathematician and engineer, who worked on hydraulics. He was born at Chamelet, Beaujolais, France and died in Asnières-sur-Seine, France.
Educati ...
, head of the École des Ponts, who wrote to
Louis-Mathieu Molé
Louis-Mathieu Molé (24 January 1781 – 23 November 1855), also 1st Count Molé from 1809 to 1815, was a French statesman, close friend and associate of Louis Philippe I, King of the French during the July Monarchy (1830–1848).
Biograph ...
, head of the Corps des Ponts, suggesting that the progress of science and the prestige of the Corps would be enhanced if Fresnel could come to Paris for a time. He arrived in March 1816, and his leave was subsequently extended through the middle of the year.
Meanwhile, in an experiment reported on 26 February 1816, Arago verified Fresnel's prediction that the internal fringes were shifted if the rays on one side of the obstacle passed through a thin glass lamina. Fresnel correctly attributed this phenomenon to the lower wave velocity in the glass. Arago later used a similar argument to explain the colors in the scintillation of stars.
[Silliman (1967, p. 163) and Frankel (1976, p. 156) give the date of Arago's note on scintillation as 1814; but the sequence of events implies 1816, in agreement with Darrigol (2012, pp. 201,290). Kipnis (1991, pp. 202–3,206) proves the later date and explains the origin and propagation of the incorrect earlier date.]
Fresnel's updated memoir was eventually published in the March 1816 issue of ''
Annales de Chimie et de Physique
__NOTOC__
''Annales de chimie et de physique'' ( French for ''Annals of Chemistry and Physics'') is a scientific journal founded in Paris, France, in 1789 under the title ''Annales de chimie''. One of the early editors was the French chemist Ant ...
'', of which Arago had recently become co-editor. That issue did not actually appear until May. In March, Fresnel already had competition: Biot read a memoir on diffraction by himself and his student
Claude Pouillet
Claude Servais Mathias Pouillet (16 February 1790 – 14 June 1868) was a French physicist and a professor of physics at the Sorbonne and member of the French Academy of Sciences (elected 1837).
Biography
He studied sciences at the École n ...
, containing copious data and arguing that the regularity of diffraction fringes, like the regularity of Newton's rings, must be linked to Newton's "fits". But the new link was not rigorous, and Pouillet himself would become a distinguished early adopter of the wave theory.
"Efficacious ray", double-mirror experiment (1816)
![Young diffraction](https://upload.wikimedia.org/wikipedia/commons/6/61/Young_diffraction.svg)
On 24 May 1816, Fresnel wrote to Young (in French), acknowledging how little of his own memoir was new. But in a "supplement" signed on 14 July and read the next day, Fresnel noted that the internal fringes were more accurately predicted by supposing that the two interfering rays came from some distance ''outside'' the edges of the obstacle. To explain this, he divided the incident wavefront at the obstacle into what we now call ''
Fresnel zone
A Fresnel zone ( ), named after physicist Augustin-Jean Fresnel, is one of a series of confocal prolate ellipsoidal regions of space between and around a transmitter and a receiver. The primary wave will travel in a relative straight line fro ...
s'', such that the secondary waves from each zone were spread over half a cycle when they arrived at the observation point. The zones on one side of the obstacle largely canceled out in pairs, except the first zone, which was represented by an "efficacious ray". This approach worked for the internal fringes, but the superposition of the efficacious ray and the direct ray did ''not'' work for the ''external'' fringes.
The contribution from the "efficacious ray" was thought to be only ''partly'' canceled, for reasons involving the dynamics of the medium: where the wavefront was continuous, symmetry forbade oblique vibrations; but near the obstacle that truncated the wavefront, the asymmetry allowed some sideways vibration towards the geometric shadow. This argument showed that Fresnel had not (yet) fully accepted Huygens's principle, which would have permitted oblique radiation from all portions of the front.
In the same supplement, Fresnel described his well-known double mirror, comprising two flat mirrors joined at an angle of slightly less than 180°, with which he produced a two-slit interference pattern from two virtual images of the same slit. A conventional double-slit experiment required a preliminary ''single'' slit to ensure that the light falling on the double slit was ''
coherent
Coherence, coherency, or coherent may refer to the following:
Physics
* Coherence (physics), an ideal property of waves that enables stationary (i.e. temporally and spatially constant) interference
* Coherence (units of measurement), a deri ...
'' (synchronized). In Fresnel's version, the preliminary single slit was retained, and the double slit was replaced by the double mirror – which bore no physical resemblance to the double slit and yet performed the same function. This result (which had been announced by Arago in the March issue of the ''Annales'') made it hard to believe that the two-slit pattern had anything to do with corpuscles being deflected as they passed near the edges of the slits.
But 1816 was the "
Year Without a Summer
The year 1816 is known as the Year Without a Summer because of severe climate abnormalities that caused average global temperatures to decrease by . Summer temperatures in Europe were the extreme weather, coldest on record between the years of 1 ...
": crops failed; hungry farming families lined the streets of Rennes; the central government organized "charity workhouses" for the needy; and in October, Fresnel was sent back to Ille-et-Vilaine to supervise charity workers in addition to his regular road crew. According to Arago,
Fresnel's letters from December 1816 reveal his consequent anxiety. To Arago he complained of being "tormented by the worries of surveillance, and the need to reprimand…" And to Mérimée he wrote: "I find nothing more tiresome than having to manage other men, and I admit that I have no idea what I'm doing."
Prize memoir (1818) and sequel
On 17 March 1817, the Académie des Sciences announced that diffraction would be the topic for the biannual physics ''Grand Prix'' to be awarded in 1819. The deadline for entries was set at 1 August 1818 to allow time for replication of experiments. Although the wording of the problem referred to rays and inflection and did not invite wave-based solutions, Arago and Ampère encouraged Fresnel to enter.
In the fall of 1817, Fresnel, supported by de Prony, obtained a leave of absence from the new head of the Corp des Ponts,
Louis Becquey, and returned to Paris. He resumed his engineering duties in the spring of 1818; but from then on he was based in Paris, first on the
Canal de l'Ourcq
The Canal de l'Ourcq is a long canal in the Île-de-France region (greater Paris) with 10 locks. It was built at a width of but was enlarged to 3.7 m (12 ft), which permitted use by more pleasure boats. The canal begins at Port-au ...
, and then (from May 1819) with the
cadastre
A cadastre or cadaster is a comprehensive recording of the real estate or real property's metes and bounds, metes-and-bounds of a country.Jo Henssen, ''Basic Principles of the Main Cadastral Systems in the World,'/ref>
Often it is represented gra ...
of the pavements.
On 15 January 1818, in a different context (revisited below), Fresnel showed that the addition of sinusoidal functions of the same frequency but different phases is analogous to the addition of forces with different directions. His method was similar to the
phasor
In physics and engineering, a phasor (a portmanteau of phase vector) is a complex number representing a sinusoidal function whose amplitude (''A''), angular frequency (''ω''), and initial phase (''θ'') are time-invariant. It is related to ...
representation, except that the "forces" were plane
vectors rather than
complex number
In mathematics, a complex number is an element of a number system that extends the real numbers with a specific element denoted , called the imaginary unit and satisfying the equation i^= -1; every complex number can be expressed in the form ...
s; they could be added, and multiplied by
scalars
Scalar may refer to:
*Scalar (mathematics), an element of a field, which is used to define a vector space, usually the field of real numbers
*Scalar (physics), a physical quantity that can be described by a single element of a number field such a ...
, but not (yet) multiplied and divided by each other. The explanation was algebraic rather than geometric.
Knowledge of this method was assumed in a preliminary note on diffraction, dated 19 April 1818 and deposited on 20 April, in which Fresnel outlined the elementary theory of diffraction as found in modern textbooks. He restated Huygens's principle in combination with the
superposition principle
The superposition principle, also known as superposition property, states that, for all linear systems, the net response caused by two or more stimuli is the sum of the responses that would have been caused by each stimulus individually. So tha ...
, saying that the vibration at each point on a wavefront is the sum of the vibrations that would be sent to it at that moment by all the elements of the wavefront in any of its previous positions, all elements acting separately . For a wavefront partly obstructed in a previous position, the summation was to be carried out over the unobstructed portion. In directions other than the normal to the primary wavefront, the secondary waves were weakened due to obliquity, but weakened much more by destructive interference, so that the effect of obliquity alone could be ignored. For diffraction by a straight edge, the intensity as a function of distance from the geometric shadow could then be expressed with sufficient accuracy in terms of what are now called the normalized
Fresnel integrals
250px,
Plots of and . The maximum of is about . If the integrands of and were defined using instead of , then the image would be scaled vertically and horizontally (see below).
The Fresnel integrals and are two transcendental functions n ...
:
![Fresnelintegral-4](https://upload.wikimedia.org/wikipedia/commons/4/45/Fresnelintegral-4.svg)
::
The same note included a table of the integrals, for an upper limit ranging from 0 to 5.1 in steps of 0.1, computed with a mean error of 0.0003, plus a smaller table of maxima and minima of the resulting intensity.
In his final "Memoir on the diffraction of light", deposited on 29 July and bearing the Latin epigraph "''Natura simplex et fecunda''" ("Nature simple and fertile"), Fresnel slightly expanded the two tables without changing the existing figures, except for a correction to the first minimum of intensity. For completeness, he repeated his solution to "the problem of interference", whereby sinusoidal functions are added like vectors. He acknowledged the directionality of the secondary sources and the variation in their distances from the observation point, chiefly to explain why these things make negligible difference in the context, provided of course that the secondary sources do not radiate in the retrograde direction. Then, applying his theory of interference to the secondary waves, he expressed the intensity of light diffracted by a single straight edge (half-plane) in terms of integrals which involved the dimensions of the problem, but which could be converted to the normalized forms above. With reference to the integrals, he explained the calculation of the maxima and minima of the intensity (external fringes), and noted that the calculated intensity falls very rapidly as one moves into the geometric shadow. The last result, as Olivier Darrigol says, "amounts to a proof of the rectilinear propagation of light in the wave theory, indeed the first proof that a modern physicist would still accept."
For the experimental testing of his calculations, Fresnel used red light with a wavelength of 638nm, which he deduced from the diffraction pattern in the simple case in which light incident on a single slit was focused by a cylindrical lens. For a variety of distances from the source to the obstacle and from the obstacle to the field point, he compared the calculated and observed positions of the fringes for diffraction by a half-plane, a slit, and a narrow strip – concentrating on the minima, which were visually sharper than the maxima. For the slit and the strip, he could not use the previously computed table of maxima and minima; for each combination of dimensions, the intensity had to be expressed in terms of sums or differences of Fresnel integrals and calculated from the table of integrals, and the extrema had to be calculated anew. The agreement between calculation and measurement was better than 1.5% in almost every case.
Near the end of the memoir, Fresnel summed up the difference between Huygens's use of secondary waves and his own: whereas Huygens says there is light only where the secondary waves exactly agree, Fresnel says there is complete darkness only where the secondary waves exactly cancel out.
![Simeon Poisson](https://upload.wikimedia.org/wikipedia/commons/b/b7/Simeon_Poisson.jpg)
The judging committee comprised Laplace, Biot, and
Poisson (all corpuscularists),
Gay-Lussac
Joseph Louis Gay-Lussac (, , ; 6 December 1778 – 9 May 1850) was a French chemist and physicist. He is known mostly for his discovery that water is made of two parts hydrogen and one part oxygen (with Alexander von Humboldt), for two laws ...
(uncommitted), and Arago, who eventually wrote the committee's report. Although entries in the competition were supposed to be anonymous to the judges, Fresnel's must have been recognizable by the content. There was only one other entry, of which neither the manuscript nor any record of the author has survived. That entry (identified as "no.1") was mentioned only in the last paragraph of the judges' report, noting that the author had shown ignorance of the relevant earlier works of Young and Fresnel, used insufficiently precise methods of observation, overlooked known phenomena, and made obvious errors. In the words of
John Worrall, "The competition facing Fresnel could hardly have been less stiff." We may infer that the committee had only two options: award the prize to Fresnel ("no. 2"), or withhold it.
![A photograph of the Arago spot](https://upload.wikimedia.org/wikipedia/commons/7/77/A_photograph_of_the_Arago_spot.png)
The committee deliberated into the new year. Then Poisson, exploiting a case in which Fresnel's theory gave easy integrals, predicted that if a circular obstacle were illuminated by a point-source, there should be (according to the theory) a bright spot in the center of the shadow, illuminated as brightly as the exterior. This seems to have been intended as a ''
reductio ad absurdum
In logic, (Latin for "reduction to absurdity"), also known as (Latin for "argument to absurdity") or ''apagogical arguments'', is the form of argument that attempts to establish a claim by showing that the opposite scenario would lead to absu ...
''. Arago, undeterred, assembled an experiment with an obstacle 2mm in diameter – and there, in the center of the shadow, was
Poisson's spot.
The unanimous report of the committee, read at the meeting of the Académie on 15 March 1819, awarded the prize to "the memoir marked no. 2, and bearing as epigraph: ''Natura simplex et fecunda''." At the same meeting, after the judgment was delivered, the president of the Académie opened a sealed note accompanying the memoir, revealing the author as Fresnel. The award was announced at the public meeting of the Académie a week later, on 22 March.
Arago's verification of Poisson's counter-intuitive prediction passed into folklore as if it had decided the prize. That view, however, is not supported by the judges' report, which gave the matter only two sentences in the penultimate paragraph. Neither did Fresnel's triumph immediately convert Laplace, Biot, and Poisson to the wave theory, for at least four reasons. First, although the professionalization of science in France had established common standards, it was one thing to acknowledge a piece of research as meeting those standards, and another thing to regard it as conclusive.
Second, it was possible to interpret Fresnel's integrals as rules for combining ''rays''. Arago even encouraged that interpretation, presumably in order to minimize resistance to Fresnel's ideas. Even Biot began teaching the Huygens-Fresnel principle without committing himself to a wave basis. Third, Fresnel's theory did not adequately explain the mechanism of generation of secondary waves or why they had any significant angular spread; this issue particularly bothered Poisson. Fourth, the question that most exercised optical physicists at that time was not diffraction, but polarization – on which Fresnel had been working, but was yet to make his critical breakthrough.
Polarization
Background: Emissionism and selectionism
An ''emission'' theory of light was one that regarded the propagation of light as the transport of some kind of matter. While the corpuscular theory was obviously an emission theory, the converse did not follow: in principle, one could be an emissionist without being a corpuscularist. This was convenient because, beyond the ordinary laws of reflection and refraction, emissionists never managed to make testable quantitative predictions from a theory of forces acting on corpuscles of light. But they ''did'' make quantitative predictions from the premises that rays were countable objects, which were conserved in their interactions with matter (except absorbent media), and which had particular orientations with respect to their directions of propagation. According to this framework, polarization and the related phenomena of double refraction and partial reflection involved altering the orientations of the rays and/or selecting them according to orientation, and the state of polarization of a beam (a bundle of rays) was a question of how many rays were in what orientations: in a fully polarized beam, the orientations were all the same. This approach, which
Jed Buchwald
Jed Z. Buchwald is Doris and Henry Dreyfuss Professor of History at Caltech. He was previously director of the Dibner Institute for the History of Science and Technology at MIT. He won a MacArthur Fellowship in 1995 and was elected to the American ...
has called ''selectionism'', was pioneered by Malus and diligently pursued by Biot.
Fresnel, in contrast, decided to introduce polarization into interference experiments.
Interference of polarized light, chromatic polarization (1816–21)
In July or August 1816, Fresnel discovered that when a birefringent crystal produced two images of a single slit, he could ''not'' obtain the usual two-slit interference pattern, even if he compensated for the different propagation times. A more general experiment, suggested by Arago, found that if the two beams of a double-slit device were separately polarized, the interference pattern appeared and disappeared as the polarization of one beam was rotated, giving full interference for parallel polarizations, but no interference for perpendicular polarizations . These experiments, among others, were eventually reported in a brief memoir published in 1819 and later translated into English.
In a memoir drafted on 30 August 1816 and revised on 6 October, Fresnel reported an experiment in which he placed two matching thin laminae in a double-slit apparatus – one over each slit, with their optic axes perpendicular – and obtained two interference patterns offset in opposite directions, with perpendicular polarizations. This, in combination with the previous findings, meant that each lamina split the incident light into perpendicularly polarized components with different velocities – just like a normal (thick) birefringent crystal, and contrary to Biot's "mobile polarization" hypothesis.
Accordingly, in the same memoir, Fresnel offered his first attempt at a wave theory of chromatic polarization. When polarized light passed through a crystal lamina, it was split into ordinary and extraordinary waves (with intensities described by Malus's law), and these were perpendicularly polarized and therefore did not interfere, so that no colors were produced (yet). But if they then passed through an ''analyzer'' (second polarizer), their polarizations were brought into alignment (with intensities again modified according to Malus's law), and they would interfere. This explanation, by itself, predicts that if the analyzer is rotated 90°, the ordinary and extraordinary waves simply switch roles, so that if the analyzer takes the form of a calcite crystal, the two images of the lamina should be of the same hue (this issue is revisited below). But in fact, as Arago and Biot had found, they are of complementary colors. To correct the prediction, Fresnel proposed a phase-inversion rule whereby ''one'' of the constituent waves of ''one'' of the two images suffered an additional 180° phase shift on its way through the lamina. This inversion was a weakness in the theory relative to Biot's, as Fresnel acknowledged, although the rule specified which of the two images had the inverted wave. Moreover, Fresnel could deal only with special cases, because he had not yet solved the problem of superposing sinusoidal functions with arbitrary phase differences due to propagation at different velocities through the lamina.
He solved that problem in a "supplement" signed on 15 January 1818 (mentioned above). In the same document, he accommodated Malus's law by proposing an underlying law: that if polarized light is incident on a birefringent crystal with its optic axis at an angle ''θ'' to the "plane of polarization", the ordinary and extraordinary vibrations (as functions of time) are scaled by the factors cos''θ'' and sin''θ'', respectively. Although modern readers easily interpret these factors in terms of perpendicular components of a ''transverse'' oscillation, Fresnel did not (yet) explain them that way. Hence he still needed the phase-inversion rule. He applied all these principles to a case of chromatic polarization not covered by Biot's formulae, involving ''two'' successive laminae with axes separated by 45°, and obtained predictions that disagreed with Biot's experiments (except in special cases) but agreed with his own.
Fresnel applied the same principles to the standard case of chromatic polarization, in which ''one'' birefringent lamina was sliced parallel to its axis and placed between a polarizer and an analyzer. If the analyzer took the form of a thick calcite crystal with its axis in the plane of polarization, Fresnel predicted that the intensities of the ordinary and extraordinary images of the lamina were respectively proportional to
::
::
where
is the angle from the initial plane of polarization to the optic axis of the lamina,
is the angle from the initial plane of polarization to the plane of polarization of the final ordinary image, and
is the phase lag of the extraordinary wave relative to the ordinary wave due to the difference in propagation times through the lamina. The terms in
are the frequency-dependent terms and explain why the lamina must be ''thin'' in order to produce discernible colors: if the lamina is too thick,
will pass through too many cycles as the frequency varies through the visible range, and the eye (which divides the visible spectrum into only
three bands) will not be able to resolve the cycles.
From these equations it is easily verified that
for all
so that the colors are complementary. Without the phase-inversion rule, there would be a ''plus'' sign in front of the last term in the second equation, so that the
-dependent term would be the same in both equations, implying (incorrectly) that the colors were of the same hue.
These equations were included in an undated note that Fresnel gave to Biot, to which Biot added a few lines of his own. If we substitute
::
and
then Fresnel's formulae can be rewritten as
::
::
which are none other than Biot's empirical formulae of 1812, except that Biot interpreted
and
as the "unaffected" and "affected" selections of the rays incident on the lamina. If Biot's substitutions were accurate, they would imply that his experimental results were more fully explained by Fresnel's theory than by his own.
Arago delayed reporting on Fresnel's works on chromatic polarization until June 1821, when he used them in a broad attack on Biot's theory. In his written response, Biot protested that Arago's attack went beyond the proper scope of a report on the nominated works of Fresnel. But Biot also claimed that the substitutions for
and
and therefore Fresnel's expressions for
and
were empirically wrong because when Fresnel's intensities of spectral colors were mixed according to Newton's rules, the squared cosine and sine functions varied too smoothly to account for the observed sequence of colors. That claim drew a written reply from Fresnel, who disputed whether the colors changed as abruptly as Biot claimed, and whether the human eye could judge color with sufficient objectivity for the purpose. On the latter question, Fresnel pointed out that different observers may give different names to the same color. Furthermore, he said, a single observer can only compare colors side by side; and even if they are judged to be the same, the identity is of sensation, not necessarily of composition. Fresnel's oldest and strongest point – that thin crystals were subject to the same laws as thick ones and did not need or allow a separate theory – Biot left unanswered. Arago and Fresnel were seen to have won the debate.
Moreover, by this time Fresnel had a new, simpler explanation of his equations on chromatic polarization.
Breakthrough: Pure transverse waves (1821)
![Andre-marie-ampere2](https://upload.wikimedia.org/wikipedia/commons/7/74/Andre-marie-ampere2.jpg)
In the draft memoir of 30 August 1816, Fresnel mentioned two hypotheses – one of which he attributed to Ampère – by which the non-interference of orthogonally-polarized beams could be explained if polarized light waves were ''partly''
transverse
Transverse may refer to:
*Transverse engine, an engine in which the crankshaft is oriented side-to-side relative to the wheels of the vehicle
*Transverse flute, a flute that is held horizontally
* Transverse force (or ''Euler force''), the tangen ...
. But Fresnel could not develop either of these ideas into a comprehensive theory. As early as September 1816, according to his later account, he realized that the non-interference of orthogonally-polarized beams, together with the phase-inversion rule in chromatic polarization, would be most easily explained if the waves were ''purely'' transverse, and Ampère "had the same thought" on the phase-inversion rule. But that would raise a new difficulty: as natural light seemed to be ''un''polarized and its waves were therefore presumed to be longitudinal, one would need to explain how the longitudinal component of vibration disappeared on polarization, and why it did not reappear when polarized light was reflected or refracted obliquely by a glass plate.
Independently, on 12 January 1817, Young wrote to Arago (in English) noting that a transverse vibration would constitute a polarization, and that if two longitudinal waves crossed at a significant angle, they could not cancel without leaving a residual transverse vibration. Young repeated this idea in an article published in a supplement to the ''Encyclopædia Britannica'' in February 1818, in which he added that Malus's law would be explained if polarization consisted in a transverse motion.
Thus Fresnel, by his own testimony, may not have been the first person to suspect that light waves could have a transverse ''component'', or that ''polarized'' waves were exclusively transverse. And it was Young, not Fresnel, who first ''published'' the idea that polarization depends on the orientation of a transverse vibration. But these incomplete theories had not reconciled the nature of polarization with the apparent existence of ''unpolarized'' light; that achievement was to be Fresnel's alone.
In a note that Buchwald dates in the summer of 1818, Fresnel entertained the idea that unpolarized waves could have vibrations of the same energy and obliquity, with their orientations distributed uniformly about the wave-normal, and that the degree of polarization was the degree of ''non''-uniformity in the distribution. Two pages later he noted, apparently for the first time in writing, that his phase-inversion rule and the non-interference of orthogonally-polarized beams would be easily explained if the vibrations of fully polarized waves were "perpendicular to the normal to the wave"—that is, purely transverse.
But if he could account for ''lack'' of polarization by averaging out the transverse component, he did not also need to assume a longitudinal component. It was enough to suppose that light waves are ''purely'' transverse, hence ''always'' polarized in the sense of having a particular transverse orientation, and that the "unpolarized" state of natural or "direct" light is due to rapid and random variations in that orientation, in which case two ''coherent'' portions of "unpolarized" light will still interfere because their orientations will be synchronized.
It is not known exactly when Fresnel made this last step, because there is no relevant documentation from 1820 or early 1821 (perhaps because he was too busy working on lighthouse-lens prototypes; see
below
Below may refer to:
*Earth
*Ground (disambiguation)
*Soil
*Floor
*Bottom (disambiguation)
Bottom may refer to:
Anatomy and sex
* Bottom (BDSM), the partner in a BDSM who takes the passive, receiving, or obedient role, to that of the top or ...
). But he first ''published'' the idea in a paper on "''Calcul des teintes…''" ("calculation of the tints…"), serialized in Arago's ''Annales'' for May, June, and July 1821. In the first installment, Fresnel described "direct" (unpolarized) light as "the rapid succession of systems of waves polarized in all directions", and gave what is essentially the modern explanation of chromatic polarization, albeit in terms of the analogy between polarization and the resolution of forces in a plane, mentioning transverse waves only in a footnote. The introduction of transverse waves into the main argument was delayed to the second installment, in which he revealed the suspicion that he and Ampère had harbored since 1816, and the difficulty it raised. He continued:
According to this new view, he wrote, "the act of polarization consists not in creating these transverse movements, but in decomposing them into two fixed perpendicular directions and in separating the two components".
While selectionists could insist on interpreting Fresnel's diffraction integrals in terms of discrete, countable rays, they could not do the same with his theory of polarization. For a selectionist, the state of polarization of a beam concerned the distribution of orientations over the ''population'' of rays, and that distribution was presumed to be static. For Fresnel, the state of polarization of a beam concerned the variation of a displacement over ''time''. That displacement might be constrained but was ''not'' static, and rays were geometric constructions, ''not'' countable objects. The conceptual gap between the wave theory and selectionism had become unbridgeable.
The other difficulty posed by pure transverse waves, of course, was the apparent implication that the aether was an elastic ''solid'', except that, unlike other elastic solids, it was incapable of transmitting longitudinal waves.
[Fresnel, in an effort to show that transverse waves were not absurd, suggested that the aether was a fluid comprising a lattice of molecules, adjacent layers of which would resist a sliding displacement up to a certain point, beyond which they would gravitate towards a new equilibrium. Such a medium, he thought, would behave as a solid for sufficiently small deformations, but as a perfect liquid for larger deformations. Concerning the lack of longitudinal waves, he further suggested that the layers offered incomparably greater resistance to a change of spacing than to a sliding motion (Silliman, 1967, pp. 216–8; Fresnel, 1821a, §§ 11–12; cf. Fresnel, 1827, tr. Hobson, pp. 258–62).] The wave theory was cheap on assumptions, but its latest assumption was expensive on credulity. If that assumption was to be widely entertained, its explanatory power would need to be impressive.
Partial reflection (1821)
In the second installment of "Calcul des teintes" (June 1821), Fresnel supposed, by analogy with
sound
In physics, sound is a vibration that propagates as an acoustic wave, through a transmission medium such as a gas, liquid or solid.
In human physiology and psychology, sound is the ''reception'' of such waves and their ''perception'' by the ...
waves, that the density of the aether in a refractive medium was inversely proportional to the square of the wave velocity, and therefore directly proportional to the square of the refractive index. For reflection and refraction at the surface between two isotropic media of different indices, Fresnel decomposed the transverse vibrations into two perpendicular components, now known as the ''s'' and ''p'' components, which are parallel to the ''surface'' and the ''plane'' of incidence, respectively; in other words, the ''s'' and ''p'' components are respectively ''square'' and ''parallel'' to the plane of incidence.
[The ''s'' originally comes from the German ''senkrecht'', meaning perpendicular (to the plane of incidence).] For the ''s'' component, Fresnel supposed that the interaction between the two media was analogous to an
elastic collision
In physics, an elastic collision is an encounter (collision) between two bodies in which the total kinetic energy of the two bodies remains the same. In an ideal, perfectly elastic collision, there is no net conversion of kinetic energy into o ...
, and obtained a formula for what we now call the ''
reflectivity
The reflectance of the surface of a material is its effectiveness in reflecting radiant energy. It is the fraction of incident electromagnetic power that is reflected at the boundary. Reflectance is a component of the response of the electronic ...
'': the ratio of the reflected intensity to the incident intensity. The predicted reflectivity was non-zero at all angles.
The third installment (July 1821) was a short "postscript" in which Fresnel announced that he had found, by a "mechanical solution", a formula for the reflectivity of the ''p'' component, which predicted that ''the reflectivity was zero at the Brewster angle''. So polarization by reflection had been accounted for – but with the proviso that the direction of vibration in Fresnel's model was ''perpendicular'' to the plane of polarization as defined by Malus. (On the ensuing controversy, see ''
Plane of polarization
The term ''plane of polarization'' refers to the direction of polarization of '' linearly-polarized'' light or other electromagnetic radiation. Unfortunately the term is used with two contradictory meanings. As originally defined by Étienne-Lou ...
''.) The technology of the time did not allow the ''s'' and ''p'' reflectivities to be measured accurately enough to test Fresnel's formulae at arbitrary angles of incidence. But the formulae could be rewritten in terms of what we now call the ''
reflection coefficient
In physics and electrical engineering the reflection coefficient is a parameter that describes how much of a wave is reflected by an impedance discontinuity in the transmission medium. It is equal to the ratio of the amplitude of the reflected wa ...
'': the signed ratio of the reflected amplitude to the incident amplitude. Then, if the plane of polarization of the incident ray was at 45° to the plane of incidence, the tangent of the corresponding angle for the reflected ray was obtainable from the ''ratio'' of the two reflection coefficients, and this angle could be measured. Fresnel had measured it for a range of angles of incidence, for glass and water, and the agreement between the calculated and measured angles was better than 1.5° in all cases.
Fresnel gave details of the "mechanical solution" in a memoir read to the Académie des Sciences on 7 January 1823. Conservation of energy was combined with continuity of the ''tangential'' vibration at the interface. The resulting formulae for the reflection coefficients and reflectivities became known as the ''
Fresnel equations
The Fresnel equations (or Fresnel coefficients) describe the reflection and transmission of light (or electromagnetic radiation in general) when incident on an interface between different optical media. They were deduced by Augustin-Jean Fresne ...
''. The reflection coefficients for the ''s'' and ''p'' polarizations are most succinctly expressed as
::
and
where
and
are the angles of incidence and refraction; these equations are known respectively as ''Fresnel's sine law'' and ''Fresnel's tangent law''. By allowing the coefficients to be ''
complex
Complex commonly refers to:
* Complexity, the behaviour of a system whose components interact in multiple ways so possible interactions are difficult to describe
** Complex system, a system composed of many components which may interact with each ...
'', Fresnel even accounted for the different phase shifts of the ''s'' and ''p'' components due to
total internal reflection
Total internal reflection (TIR) is the optical phenomenon in which waves arriving at the interface (boundary) from one medium to another (e.g., from water to air) are not refracted into the second ("external") medium, but completely reflected b ...
.
This success inspired
James MacCullagh
James MacCullagh (1809 – 24 October 1847) was an Irish mathematician.
Early Life
MacCullagh was born in Landahaussy, near Plumbridge, County Tyrone, Ireland, but the family moved to Curly Hill, Strabane when James was about 10. He was the e ...
and
Augustin-Louis Cauchy
Baron Augustin-Louis Cauchy (, ; ; 21 August 178923 May 1857) was a French mathematician, engineer, and physicist who made pioneering contributions to several branches of mathematics, including mathematical analysis and continuum mechanics. He ...
, beginning in 1836, to analyze reflection from metals by using the Fresnel equations with a
complex refractive index
In optics, the refractive index (or refraction index) of an optical medium is a dimensionless number that gives the indication of the light bending ability of that medium.
The refractive index determines how much the path of light is bent, or ...
. The same technique is applicable to non-metallic opaque media. With these generalizations, the Fresnel equations can predict the appearance of a wide variety of objects under illumination – for example, in
computer graphics
Computer graphics deals with generating images with the aid of computers. Today, computer graphics is a core technology in digital photography, film, video games, cell phone and computer displays, and many specialized applications. A great de ...
.
Circular and elliptical polarization, optical rotation (1822)
![Circular](https://upload.wikimedia.org/wikipedia/commons/d/d1/Circular.Polarization.Circularly.Polarized.Light_Left.Hand.Animation.305x190.255Colors.gif)
In a memoir dated 9 December 1822, Fresnel coined the terms ''
linear polarization
In electrodynamics, linear polarization or plane polarization of electromagnetic radiation is a confinement of the electric field vector or magnetic field vector to a given plane along the direction of propagation. The term ''linear polarizati ...
'' (French: ''polarisation rectiligne'') for the simple case in which the perpendicular components of vibration are in phase or 180° out of phase, ''
circular polarization
In electrodynamics, circular polarization of an electromagnetic wave is a polarization state in which, at each point, the electromagnetic field of the wave has a constant magnitude and is rotating at a constant rate in a plane perpendicular to t ...
'' for the case in which they are of equal magnitude and a quarter-cycle (±90°) out of phase, and ''
elliptical polarization
In electrodynamics, elliptical polarization is the polarization of electromagnetic radiation such that the tip of the electric field vector describes an ellipse in any fixed plane intersecting, and normal to, the direction of propagation. An elli ...
'' for other cases in which the two components have a fixed amplitude ratio and a fixed phase difference. He then explained how
optical rotation
Optical rotation, also known as polarization rotation or circular birefringence, is the rotation of the orientation of the plane of polarization about the optical axis of linearly polarized light as it travels through certain materials. Circul ...
could be understood as a species of birefringence. Linearly-polarized light could be resolved into two circularly-polarized components rotating in opposite directions. If these components propagated at slightly different speeds, the phase difference between them – and therefore the direction of their linearly-polarized resultant – would vary continuously with distance.
These concepts called for a redefinition of the distinction between polarized and unpolarized light. Before Fresnel, it was thought that polarization could vary in direction, and in degree (e.g., due to variation in the angle of reflection off a transparent body), and that it could be a function of color (chromatic polarization), but not that it could vary in ''kind''. Hence it was thought that the degree of polarization was the degree to which the light could be suppressed by an analyzer with the appropriate orientation. Light that had been converted from linear to elliptical or circular polarization (e.g., by passage through a crystal lamina, or by total internal reflection) was described as partly or fully "depolarized" because of its behavior in an analyzer. ''After'' Fresnel, the defining feature of polarized light was that the perpendicular components of vibration had a fixed ratio of amplitudes and a fixed difference in phase. By that definition, elliptically or circularly polarized light is ''fully'' polarized although it cannot be fully suppressed by an analyzer alone. The conceptual gap between the wave theory and selectionism had widened again.
Total internal reflection (1817–23)
![Fresnel rhomb linear to elliptical](https://upload.wikimedia.org/wikipedia/commons/b/ba/Fresnel_rhomb_linear_to_elliptical.svg)
By 1817 it had been discovered by Brewster, but not adequately reported, that plane-polarized light was partly depolarized by total internal reflection if initially polarized at an acute angle to the plane of incidence. Fresnel rediscovered this effect and investigated it by including total internal reflection in a chromatic-polarization experiment. With the aid of his ''first'' theory of chromatic polarization, he found that the apparently depolarized light was a mixture of components polarized parallel and perpendicular to the plane of incidence, and that the total reflection introduced a phase difference between them. Choosing an appropriate angle of incidence (not yet exactly specified) gave a phase difference of 1/8 of a cycle (45°). Two such reflections from the "parallel faces" of "two coupled
prism
Prism usually refers to:
* Prism (optics), a transparent optical component with flat surfaces that refract light
* Prism (geometry), a kind of polyhedron
Prism may also refer to:
Science and mathematics
* Prism (geology), a type of sedimentary ...
s" gave a phase difference of 1/4 of a cycle (90°). These findings were contained in a memoir submitted to the Académie on 10 November 1817 and read a fortnight later. An undated marginal note indicates that the two coupled prisms were later replaced by a single "parallelepiped in glass"—now known as a ''
Fresnel rhomb
A Fresnel rhomb is an optical prism that introduces a 90° phase difference between two perpendicular components of polarization, by means of two total internal reflections. If the incident beam is linearly polarized at 45° to the plane of inc ...
''.
This was the memoir whose "supplement", dated January 1818, contained the method of superposing sinusoidal functions and the restatement of Malus's law in terms of amplitudes. In the same supplement, Fresnel reported his discovery that optical rotation could be emulated by passing the polarized light through a Fresnel rhomb (still in the form of "coupled prisms"), followed by an ordinary birefringent lamina sliced parallel to its axis, with the axis at 45° to the plane of reflection of the Fresnel rhomb, followed by a second Fresnel rhomb at 90° to the first. In a further memoir read on 30 March, Fresnel reported that if polarized light was fully "depolarized" by a Fresnel rhomb – now described as a parallelepiped – its properties were not further modified by a subsequent passage through an optically rotating medium or device.
The connection between optical rotation and birefringence was further explained in 1822, in the memoir on elliptical and circular polarization. This was followed by the memoir on reflection, read in January 1823, in which Fresnel quantified the phase shifts in total internal reflection, and thence calculated the precise angle at which a Fresnel rhomb should be cut in order to convert linear polarization to circular polarization. For a refractive index of 1.51, there were two solutions: about 48.6° and 54.6°.
Double refraction
Background: Uniaxial and biaxial crystals; Biot's laws
When light passes through a slice of calcite cut perpendicular to its optic axis, the difference between the propagation times of the ordinary and extraordinary waves has a second-order dependence on the angle of incidence. If the slice is observed in a highly convergent cone of light, that dependence becomes significant, so that a chromatic-polarization experiment will show a pattern of concentric rings. But most minerals, when observed in this manner, show a more complicated pattern of rings involving two foci and a
lemniscate
In algebraic geometry, a lemniscate is any of several figure-eight or -shaped curves. The word comes from the Latin "''lēmniscātus''" meaning "decorated with ribbons", from the Greek λημνίσκος meaning "ribbons",. or which alternativel ...
curve, as if they had ''two'' optic axes. The two classes of minerals naturally become known as ''uniaxal'' and ''biaxal''—or, in later literature, ''uniaxial'' and ''biaxial''.
In 1813, Brewster observed the simple concentric pattern in "
beryl
Beryl ( ) is a mineral composed of beryllium aluminium silicate with the chemical formula Be3Al2Si6O18. Well-known varieties of beryl include emerald and aquamarine. Naturally occurring, hexagonal crystals of beryl can be up to several mete ...
,
emerald
Emerald is a gemstone and a variety of the mineral beryl (Be3Al2(SiO3)6) colored green by trace amounts of chromium or sometimes vanadium.Hurlbut, Cornelius S. Jr. and Kammerling, Robert C. (1991) ''Gemology'', John Wiley & Sons, New York, p ...
,
ruby
A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum ( aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sa ...
&c." The same pattern was later observed in calcite by
Wollaston, Biot, and
Seebeck. Biot, assuming that the concentric pattern was the general case, tried to calculate the colors with his theory of chromatic polarization, and succeeded better for some minerals than for others. In 1818, Brewster belatedly explained why: seven of the twelve minerals employed by Biot had the lemniscate pattern, which Brewster had observed as early as 1812; and the minerals with the more complicated rings also had a more complicated law of refraction.
In a uniform crystal, according to Huygens's theory, the secondary wavefront that expands from the origin in unit time is the ''ray-velocity surface''—that is, the surface whose "distance" from the origin in any direction is the ray velocity in that direction. In calcite, this surface is two-sheeted, consisting of a sphere (for the ordinary wave) and an oblate spheroid (for the extraordinary wave) touching each other at opposite points of a common axis—touching at the north and south poles, if we may use a geographic analogy. But according to Malus's ''corpuscular'' theory of double refraction, the ray velocity was proportional to the reciprocal of that given by Huygens's theory, in which case the velocity law was of the form
::
where
and
were the ordinary and extraordinary ray velocities ''according to the corpuscular theory'', and
was the angle between the ray and the optic axis. By Malus's definition, the plane of polarization of a ray was the plane of the ray and the optic axis if the ray was ordinary, or the perpendicular plane (containing the ray) if the ray was extraordinary. In Fresnel's model, the direction of vibration was normal to the plane of polarization. Hence, for the sphere (the ordinary wave), the vibration was along the lines of latitude (continuing the geographic analogy); and for the spheroid (the extraordinary wave), the vibration was along the lines of longitude.
On 29 March 1819, Biot presented a memoir in which he proposed simple generalizations of Malus's rules for a crystal with ''two'' axes, and reported that both generalizations seemed to be confirmed by experiment. For the velocity law, the squared sine was replaced by the ''product'' of the sines of the angles from the ray to the two axes (''Biot's sine law''). And for the polarization of the ordinary ray, the plane of the ray and the axis was replaced by the plane bisecting the
dihedral angle
A dihedral angle is the angle between two intersecting planes or half-planes. In chemistry, it is the clockwise angle between half-planes through two sets of three atoms, having two atoms in common. In solid geometry, it is defined as the uni ...
between the two planes each of which contained the ray and one axis (''Biot's dihedral law''). Biot's laws meant that a biaxial crystal with axes at a small angle, cleaved in the plane of those axes, behaved nearly like a uniaxial crystal at near-normal incidence; this was fortunate because
gypsum
Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywall. ...
, which had been used in chromatic-polarization experiments, is biaxial.
First memoir and supplements (1821–22)
Until Fresnel turned his attention to biaxial birefringence, it was assumed that one of the two refractions was ordinary, even in biaxial crystals. But, in a memoir submitted
[In Fresnel's collected works (1866–70), a paper is said to have been "presented" ("''présenté''") if it was merely delivered to the Permanent Secretary of the Académie for witnessing or processing (cf. vol. 1, p. 487; vol. 2, pp. 261,308). In such cases this article prefers the generic word "submitted", to avoid the impression that the paper had a formal reading.] on 19 November 1821, Fresnel reported two experiments on
topaz
Topaz is a silicate mineral of aluminium and fluorine with the chemical formula Al Si O( F, OH). It is used as a gemstone in jewelry and other adornments. Common topaz in its natural state is colorless, though trace element impurities can mak ...
showing that ''neither refraction'' was ordinary in the sense of satisfying Snell's law; that is, neither ray was the product of spherical secondary waves.
The same memoir contained Fresnel's first attempt at the biaxial velocity law. For calcite, if we interchange the equatorial and polar radii of Huygens's oblate spheroid while preserving the polar direction, we obtain a ''prolate'' spheroid touching the sphere at the equator. A plane through the center/origin cuts this prolate spheroid in an ellipse whose major and minor semi-axes give the magnitudes of the extraordinary and ordinary ray velocities in the direction normal to the plane, and (said Fresnel) the directions of their respective vibrations. The direction of the optic axis is the normal to the plane for which the ellipse of intersection reduces to a ''circle''. So, for the biaxial case, Fresnel simply replaced the prolate spheroid with a triaxial
ellipsoid
An ellipsoid is a surface that may be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation.
An ellipsoid is a quadric surface; that is, a surface that may be defined as the ...
, which was to be sectioned by a plane in the same way. In general there would be ''two'' planes passing through the center of the ellipsoid and cutting it in a circle, and the normals to these planes would give ''two'' optic axes. From the geometry, Fresnel deduced Biot's sine law (with the ray velocities replaced by their reciprocals).
The ellipsoid indeed gave the correct ray velocities (although the initial experimental verification was only approximate). But it did not give the correct directions of vibration, for the biaxial case or even for the uniaxial case, because the vibrations in Fresnel's model were tangential to the wavefront—which, for an extraordinary ray, is ''not'' generally normal to the ray. This error (which is small if, as in most cases, the birefringence is weak) was corrected in an "extract" that Fresnel read to the Académie a week later, on 26 November. Starting with Huygens's spheroid, Fresnel obtained a 4th-degree surface which, when sectioned by a plane as above, would yield the ''wave-normal velocities'' for a wavefront in that plane, together with their vibration directions. For the biaxial case, he generalized the equation to obtain a surface with three unequal principal dimensions; this he subsequently called the "surface of elasticity". But he retained the earlier ellipsoid as an approximation, from which he deduced Biot's dihedral law.
Fresnel's initial derivation of the surface of elasticity had been purely geometric, and not deductively rigorous. His first attempt at a ''mechanical'' derivation, contained in a "supplement" dated 13 January 1822, assumed that (i) there were three mutually perpendicular directions in which a displacement produced a reaction in the same direction, (ii) the reaction was otherwise a linear function of the displacement, and (iii) the radius of the surface in any direction was the square root of the component, ''in that direction'', of the reaction to a unit displacement in that direction. The last assumption recognized the requirement that if a wave was to maintain a fixed direction of propagation and a fixed direction of vibration, the reaction must not be outside the plane of those two directions.
In the same supplement, Fresnel considered how he might find, for the biaxial case, the secondary wavefront that expands from the origin in unit time—that is, the surface that reduces to Huygens's sphere and spheroid in the uniaxial case. He noted that this "wave surface" (''surface de l'onde'') is tangential to all possible plane wavefronts that could have crossed the origin one unit of time ago, and he listed the mathematical conditions that it must satisfy. But he doubted the feasibility of deriving the surface ''from'' those conditions.
In a "second supplement", Fresnel eventually exploited two related facts: (i) the "wave surface" was also the ray-velocity surface, which could be obtained by sectioning the ellipsoid that he had initially mistaken for the surface of elasticity, and (ii) the "wave surface" intersected each plane of symmetry of the ellipsoid in two curves: a circle and an ellipse. Thus he found that the "wave surface" is described by the 4th-degree equation
::
where
and
are the propagation speeds in directions normal to the coordinate axes for vibrations along the axes (the ray and wave-normal speeds being the same in those special cases). Later commentators put the equation in the more compact and memorable form
::
Earlier in the "second supplement", Fresnel modeled the medium as an array of point-masses and found that the force-displacement relation was described by a
symmetric matrix
In linear algebra, a symmetric matrix is a square matrix that is equal to its transpose. Formally,
Because equal matrices have equal dimensions, only square matrices can be symmetric.
The entries of a symmetric matrix are symmetric with re ...
, confirming the existence of three mutually perpendicular axes on which the displacement produced a parallel force. Later in the document, he noted that in a biaxial crystal, unlike a uniaxial crystal, the directions in which there is only one wave-normal velocity are not the same as those in which there is only one ray velocity. Nowadays we refer to the former directions as the ''optic'' axes or ''binormal'' axes, and the latter as the ''ray'' axes or ''biradial'' axes .
Fresnel's "second supplement" was signed on 31 March 1822 and submitted the next day – less than a year after the publication of his pure-transverse-wave hypothesis, and just less than a year after the demonstration of his prototype eight-panel lighthouse lens .
Second memoir (1822–26)
Having presented the pieces of his theory in roughly the order of discovery, Fresnel needed to rearrange the material so as to emphasize the mechanical foundations; and he still needed a rigorous treatment of Biot's dihedral law. He attended to these matters in his "second memoir" on double refraction,
[Fresnel, 1827.] published in the ''Recueils'' of the Académie des Sciences for 1824; this was not actually printed until late 1827, a few months after his death. In this work, having established the three perpendicular axes on which a displacement produces a parallel reaction, and thence constructed the surface of elasticity, he showed that Biot's dihedral law is exact provided that the binormals are taken as the optic axes, and the wave-normal direction as the direction of propagation.
As early as 1822, Fresnel discussed his perpendicular axes with
Cauchy
Baron Augustin-Louis Cauchy (, ; ; 21 August 178923 May 1857) was a French mathematician, engineer, and physicist who made pioneering contributions to several branches of mathematics, including mathematical analysis and continuum mechanics. He w ...
. Acknowledging Fresnel's influence, Cauchy went on to develop the first rigorous theory of elasticity of non-isotropic solids (1827), hence the first rigorous theory of transverse waves therein (1830) — which he promptly tried to apply to optics. The ensuing difficulties drove a long competitive effort to find an accurate mechanical model of the aether. Fresnel's own model was not dynamically rigorous; for example, it deduced the reaction to a shear strain by considering the displacement of one particle while all others were fixed, and it assumed that the stiffness determined the wave velocity as in a stretched string, whatever the direction of the wave-normal. But it was enough to enable the wave theory to do what selectionist theory could not: generate testable formulae covering a comprehensive range of optical phenomena, from ''mechanical'' assumptions.
Photoelasticity, multiple-prism experiments (1822)
![Plastic Protractor Polarized 05375](https://upload.wikimedia.org/wikipedia/commons/e/e4/Plastic_Protractor_Polarized_05375.jpg)
In 1815, Brewster reported that colors appear when a slice of isotropic material, placed between crossed polarizers, is mechanically stressed. Brewster himself immediately and correctly attributed this phenomenon to stress-induced birefringence — now known as ''
photoelasticity
Photoelasticity describes changes in the optical properties of a material under mechanical deformation. It is a property of all dielectric media and is often used to experimentally determine the stress distribution in a material, where it gives ...
''.
In a memoir read in September 1822, Fresnel announced that he had verified Brewster's diagnosis more directly, by compressing a combination of glass prisms so severely that one could actually see a double image through it. In his experiment, Fresnel lined up seven
45°-90°-45° prisms, short side to short side, with their 90° angles pointing in alternating directions. Two half-prisms were added at the ends to make the whole assembly rectangular. The prisms were separated by thin films of
turpentine
Turpentine (which is also called spirit of turpentine, oil of turpentine, terebenthene, terebinthine and (colloquially) turps) is a fluid obtained by the distillation of resin harvested from living trees, mainly pines. Mainly used as a special ...
(''
térébenthine'') to suppress internal reflections, allowing a clear line of sight along the row. When the four prisms with similar orientations were compressed in a
vise
A vise or vice (British English) is a mechanical apparatus used to secure an object to allow work to be performed on it. Vises have two parallel jaws, one fixed and the other movable, threaded in and out by a screw and lever.
A vise grip is no ...
across the line of sight, an object viewed through the assembly produced two images with perpendicular polarizations, with an apparent spacing of 1.5mm at one metre.
At the end of that memoir, Fresnel predicted that if the compressed prisms were replaced by (unstressed) monocrystalline quartz prisms with matching directions of optical rotation, and with their optic axes aligned along the row, an object seen by looking along the common optic axis would give two images, which would seem unpolarized when viewed through an analyzer but, when viewed through a Fresnel rhomb, would be polarized at ±45° to the plane of reflection of the rhomb (indicating that they were initially circularly polarized in opposite directions). This would show directly that optical rotation is a form of birefringence. In the memoir of December 1822, in which he introduced the term ''circular polarization'', he reported that he had confirmed this prediction using only one 14°-152°-14° prism and two glass half-prisms. But he obtained a wider separation of the images by replacing the glass half-prism with quartz half-prisms whose rotation was opposite to that of the 14°-152°-14° prism. He added in passing that one could further increase the separation by increasing the number of prisms.
Reception
For the supplement to Riffault's translation of
Thomson Thomson may refer to:
Names
* Thomson (surname), a list of people with this name and a description of its origin
* Thomson baronets, four baronetcies created for persons with the surname Thomson
Businesses and organizations
* SGS-Thomson Mic ...
's ''System of Chemistry'', Fresnel was chosen to contribute the article on light. The resulting 137-page essay, titled ''De la Lumière'' (''On Light''), was apparently finished in June 1821 and published by February 1822.
[Grattan-Guinness, 1990, p. 884.] With sections covering the nature of light, diffraction, thin-film interference, reflection and refraction, double refraction and polarization, chromatic polarization, and modification of polarization by reflection, it made a comprehensive case for the wave theory to a readership that was not restricted to physicists.
To examine Fresnel's first memoir and supplements on double refraction, the Académie des Sciences appointed Ampère, Arago,
Fourier, and Poisson. Their report, of which Arago was clearly the main author, was delivered at the meeting of 19 August 1822. Then, in the words of
Émile Verdet
Marcel Émile Verdet (; 13 March 1824 – 3 June 1866) was a French physicist. He worked in magnetism and optics, editing the works of Augustin-Jean Fresnel. Verdet did much to champion the early theory of the conservation of energy in France th ...
, as translated by
Ivor Grattan-Guinness
Ivor Owen Grattan-Guinness (23 June 1941 – 12 December 2014) was a historian of mathematics and logic.
Life
Grattan-Guinness was born in Bakewell, England; his father was a mathematics teacher and educational administrator. He gained his bac ...
:
Whether Laplace was announcing his conversion to the wave theory – at the age of 73 – is uncertain. Grattan-Guinness entertained the idea. Buchwald, noting that Arago failed to explain that the "ellipsoid of elasticity" did not give the correct planes of polarization, suggests that Laplace may have merely regarded Fresnel's theory as a successful generalization of Malus's ray-velocity law, embracing Biot's laws.
![Beugungsscheibchen](https://upload.wikimedia.org/wikipedia/commons/3/3a/Beugungsscheibchen.k.720.jpg)
In the following year, Poisson, who did not sign Arago's report, disputed the possibility of transverse waves in the aether. Starting from assumed equations of motion of a fluid medium, he noted that they did not give the correct results for partial reflection and double refraction – as if that were Fresnel's problem rather than his own – and that the predicted waves, even if they were initially transverse, became more longitudinal as they propagated. In reply Fresnel noted, ''inter alia'', that the equations in which Poisson put so much faith did not even predict
viscosity
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water.
Viscosity quantifies the inte ...
. The implication was clear: given that the behavior of light had not been satisfactorily explained except by transverse waves, it was not the responsibility of the wave-theorists to abandon transverse waves in deference to pre-conceived notions about the aether; rather, it was the responsibility of the aether modelers to produce a model that accommodated transverse waves. According to Robert H. Silliman, Poisson eventually accepted the wave theory shortly before his death in 1840.
Among the French, Poisson's reluctance was an exception. According to Eugene Frankel, "in Paris no debate on the issue seems to have taken place after 1825. Indeed, almost the entire generation of physicists and mathematicians who came to maturity in the 1820s – Pouillet,
Savart
The savart is a unit of measurement for musical pitch intervals (). One savart is equal to one thousandth of a decade ( 10/1: 3,986.313714 cents): 3.9863 cents. Musically, in just intonation, the interval of a decade is precisely a just major ...
,
Lamé,
Navier,
Liouville
Joseph Liouville (; ; 24 March 1809 – 8 September 1882) was a French mathematician and engineer.
Life and work
He was born in Saint-Omer in France on 24 March 1809. His parents were Claude-Joseph Liouville (an army officer) and Thérèse ...
, Cauchy – seem to have adopted the theory immediately." Fresnel's other prominent French opponent, Biot, appeared to take a neutral position in 1830, and eventually accepted the wave theory – possibly by 1846 and certainly by 1858.
In 1826, the British astronomer
John Herschel
Sir John Frederick William Herschel, 1st Baronet (; 7 March 1792 – 11 May 1871) was an English polymath active as a mathematician, astronomer, chemist, inventor, experimental photographer who invented the blueprint and did botanical wor ...
, who was working on a book-length article on light for the ''
Encyclopædia Metropolitana
''The Encyclopædia Metropolitana'' was an encyclopedic work published in London, from 1817 to 1845, by part publication. In all it came to quarto, 30 vols., having been issued in 59 parts (22,426 pages, 565 plates).
Origins
Initially the proje ...
'', addressed three questions to Fresnel concerning double refraction, partial reflection, and their relation to polarization. The resulting article, titled simply "Light", was highly sympathetic to the wave theory, although not entirely free of selectionist language. It was circulating privately by 1828 and was published in 1830. Meanwhile, Young's translation of Fresnel's ''De la Lumière'' was published in installments from 1827 to 1829.
George Biddell Airy
Sir George Biddell Airy (; 27 July 18012 January 1892) was an English mathematician and astronomer, and the seventh Astronomer Royal from 1835 to 1881. His many achievements include work on planetary orbits, measuring the mean density of the E ...
, the former
Lucasian Professor at
Cambridge
Cambridge ( ) is a university city and the county town in Cambridgeshire, England. It is located on the River Cam approximately north of London. As of the 2021 United Kingdom census, the population of Cambridge was 145,700. Cambridge bec ...
and future
Astronomer Royal
Astronomer Royal is a senior post in the Royal Households of the United Kingdom. There are two officers, the senior being the Astronomer Royal dating from 22 June 1675; the junior is the Astronomer Royal for Scotland dating from 1834.
The post ...
, unreservedly accepted the wave theory by 1831. In 1834, he famously calculated the diffraction pattern of a circular aperture from the wave theory, thereby explaining the limited
angular resolution
Angular resolution describes the ability of any image-forming device such as an optical or radio telescope, a microscope, a camera, or an eye, to distinguish small details of an object, thereby making it a major determinant of image resolution. ...
of a perfect
telescope
A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observe ...
. By the end of the 1830s, the only prominent British physicist who held out against the wave theory was
Brewster, whose objections included the difficulty of explaining
photochemical
Photochemistry is the branch of chemistry concerned with the chemical effects of light. Generally, this term is used to describe a chemical reaction caused by absorption of ultraviolet (wavelength from 100 to 400 nm), visible light (400–7 ...
effects and (in his opinion)
dispersion
Dispersion may refer to:
Economics and finance
*Dispersion (finance), a measure for the statistical distribution of portfolio returns
*Price dispersion, a variation in prices across sellers of the same item
*Wage dispersion, the amount of variatio ...
.
A German translation of ''De la Lumière'' was published in installments in 1825 and 1828. The wave theory was adopted by
Fraunhofer in the early 1820s and by
Franz Ernst Neumann
Franz Ernst Neumann (11 September 1798 – 23 May 1895) was a German mineralogist, physicist and mathematician.
Biography
Neumann was born in Joachimsthal, Margraviate of Brandenburg, near Berlin. In 1815 he interrupted his studies at Berlin to ...
in the 1830s, and then began to find favor in German textbooks.
The economy of assumptions under the wave theory was emphasized by
William Whewell
William Whewell ( ; 24 May 17946 March 1866) was an English polymath, scientist, Anglican priest, philosopher, theologian, and historian of science. He was Master of Trinity College, Cambridge. In his time as a student there, he achieved dist ...
in his ''History of the Inductive Sciences'', first published in 1837. In the corpuscular system, "every new class of facts requires a new supposition," whereas in the wave system, a hypothesis devised in order to explain one phenomenon is then found to explain or predict others. In the corpuscular system there is "no unexpected success, no happy coincidence, no convergence of principles from remote quarters"; but in the wave system, "all tends to unity and simplicity."
Hence, in 1850, when
Foucault and
Fizeau
Armand Hippolyte Louis Fizeau Royal Society of London, FRS FRSE MIF (; 23 September 181918 September 1896) was a French physicist, best known for measuring the speed of light in the namesake Fizeau experiment.
Biography
Fizeau was born in Paris t ...
found by experiment that light travels more slowly in water than in air, in accordance with the wave explanation of refraction and contrary to the corpuscular explanation, the result came as no surprise.
Lighthouses and the Fresnel lens
Fresnel was not the first person to focus a lighthouse beam using a lens. That distinction apparently belongs to the London glass-cutter Thomas Rogers, whose first lenses, 53cm in diameter and 14cm thick at the center, were installed at the
Old Lower Lighthouse
The Old Lower Lighthouse is a disused 19th century lighthouse on the Isle of Portland, Dorset, southern England. It is located along the eastern side of Portland Bill. The lighthouse, including its boundary walls and coastguard house, became ...
at
Portland Bill
Portland Bill is a narrow promontory (or bill) at the southern end of the Isle of Portland, and the southernmost point of Dorset, England. One of Portland's most popular destinations is Portland Bill Lighthouse. Portland's coast has been notorio ...
in 1789. Further samples were installed in about half a dozen other locations by 1804. But much of the light was wasted by absorption in the glass.
![Fresnel lens](https://upload.wikimedia.org/wikipedia/commons/e/e8/Fresnel_lens.svg)
Nor was Fresnel the first to suggest replacing a convex lens with a series of concentric
annular
Annulus (or anulus) or annular indicates a ring- or donut-shaped area or structure. It may refer to:
Human anatomy
* ''Anulus fibrosus disci intervertebralis'', spinal structure
* Annulus of Zinn, a.k.a. annular tendon or ''anulus tendineus com ...
prisms, to reduce weight and absorption. In 1748,
Count Buffon
Georges-Louis Leclerc, Comte de Buffon (; 7 September 1707 – 16 April 1788) was a French naturalist, mathematician, cosmologist, and encyclopédiste.
His works influenced the next two generations of naturalists, including two prominent Fr ...
proposed grinding such prisms as steps in a single piece of glass. In 1790, the
Marquis de Condorcet
Marie Jean Antoine Nicolas de Caritat, Marquis of Condorcet (; 17 September 1743 – 29 March 1794), known as Nicolas de Condorcet, was a French philosopher and mathematician. His ideas, including support for a liberal economy, free and equal pu ...
suggested that it would be easier to make the annular sections separately and assemble them on a frame; but even that was impractical at the time.
[Levitt, 2013, p. 71.] These designs were intended not for lighthouses, but for
burning glass
A burning glass or burning lens is a large convex lens that can concentrate the sun's rays onto a small area, heating up the area and thus resulting in ignition of the exposed surface. Burning mirrors achieve a similar effect by using reflecting s ...
es. Brewster, however, proposed a system similar to Condorcet's in 1811, and by 1820 was advocating its use in British lighthouses.
Meanwhile, on 21 June 1819, Fresnel was "temporarily" seconded by the ''Commission des Phares'' (Commission of Lighthouses) on the recommendation of Arago (a member of the Commission since 1813), to review possible improvements in lighthouse illumination. The commission had been established by Napoleon in 1811 and placed under the Corps des Ponts – Fresnel's employer.
By the end of August 1819, unaware of the Buffon-Condorcet-Brewster proposal, Fresnel made his first presentation to the commission, recommending what he called ''lentilles à échelons'' (lenses by steps) to replace the reflectors then in use, which reflected only about half of the incident light.
[Another report by Fresnel, dated 29 August 1819 (Fresnel, 1866–70, vol. 3, pp. 15–21), concerns tests on reflectors, and does not mention stepped lenses except in an unrelated sketch on the last page of the manuscript. The minutes of the meetings of the Commission go back only to 1824, when Fresnel himself took over as Secretary (Fresnel, 1866–70, vol. 3, p. 6n). Thus, unfortunately, it is not possible to ascertain the exact date on which Fresnel formally recommended ''lentilles à échelons''.] One of the assembled commissioners,
Jacques Charles
Jacques Alexandre César Charles (November 12, 1746 – April 7, 1823) was a French inventor, scientist, mathematician, and balloonist.
Charles wrote almost nothing about mathematics, and most of what has been credited to him was due to mistaking ...
, recalled Buffon's suggestion, leaving Fresnel embarrassed for having again "broken through an open door".
But, whereas Buffon's version was
biconvex and in one piece, Fresnel's was
plano-convex
Plano-convex may refer to:
* Plano-convex lens, in optics
* Plano-convex, a type of mudbrick
A mudbrick or mud-brick is an air-dried brick, made of a mixture of loam, mud, sand and water mixed with a binding material such as rice husks or ...
and made of multiple prisms for easier construction. With an official budget of 500 francs, Fresnel approached three manufacturers. The third, François Soleil, produced the prototype. Finished in March 1820, it had a square lens panel 55cm on a side, containing 97 polygonal (not annular) prisms – and so impressed the Commission that Fresnel was asked for a full eight-panel version. This model, completed a year later in spite of insufficient funding, had panels 76cm square. In a public spectacle on the evening of 13 April 1821, it was demonstrated by comparison with the most recent reflectors, which it suddenly rendered obsolete.
![Fresnel lighthouse lens diagram](https://upload.wikimedia.org/wikipedia/commons/a/ab/Fresnel_lighthouse_lens_diagram.png)
Fresnel's next lens was a rotating apparatus with eight "bull's-eye" panels, made in annular arcs by
Saint-Gobain
Compagnie de Saint-Gobain S.A. () is a French multinational corporation, founded in 1665 in Paris and headquartered on the outskirts of Paris, at La Défense and in Courbevoie. Originally a mirror manufacturer, it now also produces a variety of ...
,
giving eight rotating beams – to be seen by mariners as a periodic flash. Above and behind each main panel was a smaller, sloping bull's-eye panel of trapezoidal outline with trapezoidal elements. This refracted the light to a sloping plane mirror, which then reflected it horizontally, 7 degrees ahead of the main beam, increasing the duration of the flash. Below the main panels were 128 small mirrors arranged in four rings, stacked like the slats of a
louver
A louver (American English) or louvre (British English
British English (BrE, en-GB, or BE) is, according to Lexico, Oxford Dictionaries, "English language, English as used in Great Britain, as distinct from that used elsewhere". Mor ...
or
Venetian blind
A window blind is a type of window covering. There are many different kinds of window blinds which use a variety of control systems. A typical window blind is made up of several long horizontal or vertical slats of various types of hard mater ...
. Each ring, shaped as a
frustum
In geometry, a (from the Latin for "morsel"; plural: ''frusta'' or ''frustums'') is the portion of a solid (normally a pyramid or a cone) that lies between two parallel planes cutting this solid. In the case of a pyramid, the base faces are p ...
of a
cone
A cone is a three-dimensional geometric shape that tapers smoothly from a flat base (frequently, though not necessarily, circular) to a point called the apex or vertex.
A cone is formed by a set of line segments, half-lines, or lines con ...
, reflected the light to the horizon, giving a fainter steady light between the flashes. The official test, conducted on the unfinished ''
Arc de Triomphe
The Arc de Triomphe de l'Étoile (, , ; ) is one of the most famous monuments in Paris, France, standing at the western end of the Champs-Élysées at the centre of Place Charles de Gaulle, formerly named Place de l'Étoile—the ''étoile'' ...
'' on 20 August 1822, was witnessed by the commission – and by
Louis Louis may refer to:
* Louis (coin)
* Louis (given name), origin and several individuals with this name
* Louis (surname)
* Louis (singer), Serbian singer
* HMS ''Louis'', two ships of the Royal Navy
See also
Derived or associated terms
* Lewis ( ...
and his entourage – from 32km away. The apparatus was stored at
Bordeaux
Bordeaux ( , ; Gascon oc, Bordèu ; eu, Bordele; it, Bordò; es, Burdeos) is a port city on the river Garonne in the Gironde department, Southwestern France. It is the capital of the Nouvelle-Aquitaine region, as well as the prefectur ...
for the winter, and then reassembled at
Cordouan Lighthouse
Cordouan lighthouse () is an active lighthouse located at sea, near the mouth of the Gironde estuary in France. At a height of , it is the tenth-tallest "traditional lighthouse" in the world.
The Tour de Cordouan, the 'Patriarch of Lighthouses ...
under Fresnel's supervision. On 25 July 1823, the world's first lighthouse Fresnel lens was lit. Soon afterwards, Fresnel started coughing up blood.
[Levitt, 2013, p. 97.]
In May 1824, Fresnel was promoted to secretary of the ''Commission des Phares'', becoming the first member of that body to draw a salary, albeit in the concurrent role of Engineer-in-Chief. He was also an examiner (not a teacher) at the École Polytechnique since 1821; but poor health, long hours during the examination season, and anxiety about judging others induced him to resign that post in late 1824, to save his energy for his lighthouse work.
In the same year he designed the first ''fixed'' lens – for spreading light evenly around the horizon while minimizing waste above or below. Ideally the curved refracting surfaces would be segments of
toroid
In mathematics, a toroid is a surface of revolution with a hole in the middle. The axis of revolution passes through the hole and so does not intersect the surface. For example, when a rectangle is rotated around an axis parallel to one of its ...
s about a common vertical axis, so that the dioptric panel would look like a cylindrical drum. If this was supplemented by reflecting (
catoptric
Catoptrics (from grc-gre, κατοπτρικός ''katoptrikós'', "specular", from grc-gre, κάτοπτρον ''katoptron'' "mirror") deals with the phenomena of reflected light and image-forming optical systems using mirrors. A catoptric s ...
) rings above and below the refracting (dioptric) parts, the entire apparatus would look like a beehive. The second Fresnel lens to enter service was indeed a fixed lens, of third order, installed at Dunkirk by 1 February 1825. However, due to the difficulty of fabricating large toroidal prisms, this apparatus had a 16-sided polygonal plan.
In 1825, Fresnel extended his fixed-lens design by adding a rotating array outside the fixed array. Each panel of the rotating array was to refract part of the fixed light from a horizontal fan into a narrow beam.
Also in 1825, Fresnel unveiled the ''Carte des Phares'' (Lighthouse Map), calling for a system of 51 lighthouses plus smaller harbor lights, in a hierarchy of lens sizes (called ''orders'', the first order being the largest), with different characteristics to facilitate recognition: a constant light (from a fixed lens), one flash per minute (from a rotating lens with eight panels), and two per minute (sixteen panels).
![MuseeMarine-phareFresnel-p1000466](https://upload.wikimedia.org/wikipedia/commons/6/68/MuseeMarine-phareFresnel-p1000466.jpg)
In late 1825, to reduce the loss of light in the reflecting elements, Fresnel proposed to replace each mirror with a catadioptric prism, through which the light would travel by refraction through the first surface, then
total internal reflection
Total internal reflection (TIR) is the optical phenomenon in which waves arriving at the interface (boundary) from one medium to another (e.g., from water to air) are not refracted into the second ("external") medium, but completely reflected b ...
off the second surface, then refraction through the third surface. The result was the lighthouse lens as we now know it. In 1826 he assembled a small model for use on the
Canal Saint-Martin
The Canal Saint-Martin is a 4.6 km (2.86 mi) long canal in Paris, connecting the Canal de l'Ourcq to the river Seine. Over nearly half its length (), between the Rue du Faubourg du Temple and the Place de la Bastille, it was covered, in the ...
, but he did not live to see a full-sized version.
The first fixed lens with toroidal prisms was a first-order apparatus designed by the Scottish engineer
Alan Stevenson
Alan Stevenson FRSE LLD MInstCE (28 April 1807 – 23 December 1865) was a Scottish civil engineer, known for designing and building lighthouses in and around Scotland.
Life
Alan Stevenson was born in Edinburgh on 28 April 1807, the eldest ...
under the guidance of Léonor Fresnel, and fabricated by Isaac Cookson & Co. from French glass; it entered service at the
Isle of May
The Isle of May is located in the north of the outer Firth of Forth, approximately off the coast of mainland Scotland. It is about long and wide. The island is owned and managed by NatureScot as a national nature reserve. There are now no ...
in 1836. The first large catadioptric lenses were fixed third-order lenses made in 1842 for the lighthouses at Gravelines and
Île Vierge
Île Vierge (Breton language: ''Enez-Werc'h'') is a islet lying off the north-west coast of Brittany, opposite the village of Lilia. It is in the Communes of France, commune of Plouguerneau, in the Departments of France, département of Finist ...
. The first fully catadioptric ''first-order'' lens, installed at Ailly in 1852, gave eight rotating beams assisted by eight catadioptric panels at the top (to lengthen the flashes), plus a fixed light from below. The first fully catadioptric lens with ''purely revolving'' beams – also of first order – was installed at
Saint-Clément-des-Baleines
Saint-Clément-des-Baleines () is a commune on Île de Ré, a coastal island in the French department of Charente-Maritime, located in the region of Nouvelle-Aquitaine (formerly Poitou-Charentes).
Population
Geography
This commune has no harb ...
in 1854, and marked the completion of Augustin Fresnel's original ''Carte des Phares''.
![Flat flexible plastic sheet lens](https://upload.wikimedia.org/wikipedia/commons/c/cd/Flat_flexible_plastic_sheet_lens.JPG)
Production of one-piece stepped dioptric lenses—roughly as envisaged by Buffon—became practical in 1852, when John L. Gilliland of the
Brooklyn Flint-Glass Company patented a method of making such lenses from press-molded glass. By the 1950s, the substitution of plastic for glass made it economic to use fine-stepped Fresnel lenses as condensers in
overhead projector
An overhead projector (often abbreviated to OHP), like a film or slide projector, uses light to project an enlarged image on a screen, allowing the view of a small document or picture to be shared with a large audience.
In the overhead project ...
s. Still finer steps can be found in low-cost plastic "sheet"
magnifiers.
Honors
Fresnel was elected to the ''
Société Philomathique de Paris
The Philomaths, or Philomath Society ( pl, Filomaci or ''Towarzystwo Filomatów''; from the Greek φιλομαθεῖς "lovers of knowledge"), was a secret student organization that existed from 1817 to 1823 at the Imperial University of Vilniu ...
'' in April 1819,
[Kipnis, 1991, p. 217.] and in 1822 became one of the editors of the Société's ''Bulletin des Sciences''. As early as May 1817, at Arago's suggestion, Fresnel applied for membership of the Académie des Sciences, but received only one vote.
The successful candidate on that occasion was
Joseph Fourier
Jean-Baptiste Joseph Fourier (; ; 21 March 1768 – 16 May 1830) was a French people, French mathematician and physicist born in Auxerre and best known for initiating the investigation of Fourier series, which eventually developed into Fourier an ...
. In November 1822, Fourier's elevation to Permanent Secretary of the Académie created a vacancy in the physics section, which was filled in February 1823 by
Pierre Louis Dulong
Pierre Louis Dulong FRS FRSE (; ; 12 February 1785 – 19 July 1838) was a French physicist and chemist. He is remembered today largely for the law of Dulong and Petit, although he was much-lauded by his contemporaries for his studies into ...
, with 36 votes to Fresnel's 20. But in May 1823, after another vacancy was left by the death of
Jacques Charles
Jacques Alexandre César Charles (November 12, 1746 – April 7, 1823) was a French inventor, scientist, mathematician, and balloonist.
Charles wrote almost nothing about mathematics, and most of what has been credited to him was due to mistaking ...
, Fresnel's election was unanimous. In 1824, Fresnel was made a ''chevalier de la Légion d'honneur'' (Knight of the
Legion of Honour
The National Order of the Legion of Honour (french: Ordre national de la Légion d'honneur), formerly the Royal Order of the Legion of Honour ('), is the highest French order of merit, both military and civil. Established in 1802 by Napoleon, ...
).
Meanwhile, in Britain, the wave theory was yet to take hold; Fresnel wrote to Thomas Young in November 1824, saying in part:
But "the praise of English scholars" soon followed. On 9 June 1825, Fresnel was made a Foreign Member of the
Royal Society of London
The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...
. In 1827 he was awarded the society's
Rumford Medal
The Rumford Medal is an award bestowed by Britain's Royal Society every alternating year for "an outstandingly important recent discovery in the field of thermal or optical properties of matter made by a scientist working in Europe".
First awar ...
for the year 1824, "For his Development of the Undulatory Theory as applied to the Phenomena of Polarized Light, and for his various important discoveries in Physical Optics."
A monument to Fresnel at his birthplace was dedicated on 14 September 1884 with a speech by , Permanent Secretary of the Académie des Sciences. "" is among the
72 names embossed on the Eiffel Tower (on the south-east side, fourth from the left). In the 19th century, as every lighthouse in France acquired a Fresnel lens, every one acquired a bust of Fresnel, seemingly watching over the coastline that he had made safer. The lunar features ''
Promontorium Fresnel'' and ''
Rimae Fresnel'' were later named after him.
Decline and death
![Père-Lachaise - Division 14 - Fresnel 01](https://upload.wikimedia.org/wikipedia/commons/1/15/P%C3%A8re-Lachaise_-_Division_14_-_Fresnel_01.jpg)
Fresnel's health, which had always been poor, deteriorated in the winter of 1822–1823, increasing the urgency of his original research, and (in part) preventing him from contributing an article on polarization and double refraction for the ''
Encyclopædia Britannica
The (Latin for "British Encyclopædia") is a general knowledge English-language encyclopaedia. It is published by Encyclopædia Britannica, Inc.; the company has existed since the 18th century, although it has changed ownership various time ...
''. The memoirs on circular and elliptical polarization and optical rotation, and on the detailed derivation of the Fresnel equations and their application to total internal reflection, date from this period. In the spring he recovered enough, in his own view, to supervise the lens installation at Cordouan. Soon afterwards, it became clear that his condition was
tuberculosis
Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in ...
.
In 1824, he was advised that if he wanted to live longer, he needed to scale back his activities. Perceiving his lighthouse work to be his most important duty, he resigned as an examiner at the École Polytechnique, and closed his scientific notebooks. His last note to the Académie, read on 13 June 1825, described the first
radiometer
A radiometer or roentgenometer is a device for measuring the radiant flux (power) of electromagnetic radiation. Generally, a radiometer is an infrared radiation detector or an ultraviolet detector. Microwave radiometers operate in the microwave w ...
and attributed the observed repulsive force to a temperature difference. Although his fundamental research ceased, his advocacy did not; as late as August or September 1826, he found the time to answer
Herschel's queries on the wave theory. It was Herschel who recommended Fresnel for the Royal Society's Rumford Medal.
Fresnel's cough worsened in the winter of 1826–1827, leaving him too ill to return to Mathieu in the spring. The Académie meeting of 30 April 1827 was the last that he attended. In early June he was carried to
Ville-d'Avray
Ville-d'Avray () is a Communes of France, commune in the western suburbs of Paris, France. It is located from the Kilometre zero, centre of Paris. The commune is part of the arrondissement of Boulogne-Billancourt in the Hauts-de-Seine Department ...
, west of Paris. There his mother joined him. On 6 July, Arago arrived to deliver the Rumford Medal. Sensing Arago's distress, Fresnel whispered that "the most beautiful crown means little, when it is laid on the grave of a friend." Fresnel did not have the strength to reply to the Royal Society. He died eight days later, on
Bastille Day
Bastille Day is the common name given in English-speaking countries to the national day of France, which is celebrated on 14 July each year. In French, it is formally called the (; "French National Celebration"); legally it is known as (; "t ...
.
He is buried at
Père Lachaise Cemetery
Père Lachaise Cemetery (french: Cimetière du Père-Lachaise ; formerly , "East Cemetery") is the largest cemetery in Paris, France (). With more than 3.5 million visitors annually, it is the most visited necropolis in the world. Notable figures ...
, Paris. The
inscription on his headstone is partly eroded away; the legible part says, when translated, "To the memory of Augustin Jean Fresnel, member of the
Institute of France
The (; ) is a French learned society, grouping five , including the Académie Française. It was established in 1795 at the direction of the National Convention. Located on the Quai de Conti in the 6th arrondissement of Paris, the institute m ...
".
Posthumous publications
![Emile Verdet](https://upload.wikimedia.org/wikipedia/commons/6/66/Emile_Verdet.png)
Fresnel's "second memoir" on double refraction
was not printed until late 1827, a few months after his death. Until then, the best published source on his work on double refraction was an extract of that memoir, printed in 1822. His final treatment of partial reflection and total internal reflection, read to the Académie in January 1823, was thought to be lost until it was rediscovered among the papers of the deceased
Joseph Fourier
Jean-Baptiste Joseph Fourier (; ; 21 March 1768 – 16 May 1830) was a French people, French mathematician and physicist born in Auxerre and best known for initiating the investigation of Fourier series, which eventually developed into Fourier an ...
(1768–1830), and was printed in 1831. Until then, it was known chiefly through an extract printed in 1823 and 1825. The memoir introducing the parallelepiped form of the Fresnel rhomb, read in March 1818, was mislaid until 1846, and then attracted such interest that it was soon republished in English. Most of Fresnel's writings on polarized light before 1821 – including his first theory of chromatic polarization (submitted 7 October 1816) and the crucial "supplement" of January 1818 — were not published in full until his ''Oeuvres complètes'' ("complete works") began to appear in 1866. The "supplement" of July 1816, proposing the "efficacious ray" and reporting the famous double-mirror experiment, met the same fate, as did the "first memoir" on double refraction.
Publication of Fresnel's collected works was itself delayed by the deaths of successive editors. The task was initially entrusted to
Félix Savary Félix Savary, who was born on 4 October 1797 in Paris and died on 15 July 1841 in Estagel, was a French astronomer. , who died in 1841. It was restarted twenty years later by the Ministry of Public Instruction. Of the three editors eventually named in the ''Oeuvres'',
Sénarmont died in 1862,
Verdet in 1866, and Léonor Fresnel in 1869, by which time only two of the three volumes had appeared. At the beginning of vol. 3 (1870), the completion of the project is described in a long footnote by "
J. Lissajous."
Not included in the ''Oeuvres'' are two short notes by Fresnel on magnetism, which were discovered among Ampère's manuscripts. In response to
Ørsted's discovery of
electromagnetism
In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions of a ...
in 1820, Ampère initially supposed that the field of a permanent
magnet
A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, ...
was due to a macroscopic circulating
current
Currents, Current or The Current may refer to:
Science and technology
* Current (fluid), the flow of a liquid or a gas
** Air current, a flow of air
** Ocean current, a current in the ocean
*** Rip current, a kind of water current
** Current (stre ...
. Fresnel suggested instead that there was a ''microscopic'' current circulating around each particle of the magnet. In his first note, he argued that microscopic currents, unlike macroscopic currents, would explain why a hollow cylindrical magnet does not lose its magnetism when cut longitudinally. In his second note, dated 5 July 1821, he further argued that a macroscopic current had the counterfactual implication that a permanent magnet should be hot, whereas microscopic currents circulating around the molecules might avoid the heating mechanism. He was not to know that the fundamental units of permanent magnetism are even smaller than molecules . The two notes, together with Ampère's acknowledgment, were eventually published in 1885.
Lost works
Fresnel's essay ''Rêveries'' of 1814 has not survived. While its content would have been interesting to historians, its quality may perhaps be gauged from the fact that Fresnel himself never referred to it in his maturity.
More disturbing is the fate of the late article "Sur les Différents Systèmes relatifs à la Théorie de la Lumière" ("On the Different Systems relating to the Theory of Light"), which Fresnel wrote for the newly launched English journal ''European Review''. This work seems to have been similar in scope to the essay ''De la Lumière'' of 1821/22, except that Fresnel's views on double refraction, circular and elliptical polarization, optical rotation, and total internal reflection had developed since then. The manuscript was received by the publisher's agent in Paris in early September 1824, and promptly forwarded to London. But the journal failed before Fresnel's contribution could be published. Fresnel tried unsuccessfully to recover the manuscript. The editors of his collected works were also unable to find it, and admitted that it was probably lost.
Unfinished business
Aether drag and aether density
In 1810, Arago found experimentally that the degree of refraction of starlight does not depend on the direction of the earth's motion relative to the line of sight. In 1818, Fresnel showed that this result could be explained by the wave theory, on the hypothesis that if an object with refractive index
moved at velocity
relative to the external aether (taken as stationary), then the velocity of light inside the object gained the additional component
. He supported that hypothesis by supposing that if the density of the external aether was taken as unity, the density of the internal aether was
, of which the excess, namely
, was dragged along at velocity
, whence the ''average'' velocity of the internal aether was
. The factor in parentheses, which Fresnel originally expressed in terms of wavelengths, became known as the ''Fresnel drag coefficient''.
In his analysis of double refraction, Fresnel supposed that the different refractive indices in different directions within the ''same medium'' were due to a directional variation in elasticity, not density (because the concept of mass per unit volume is not directional). But in his treatment of partial reflection, he supposed that the different refractive indices of ''different media'' were due to different aether densities, not different elasticities. The latter decision, although puzzling in the context of double refraction, was consistent with the earlier treatment of aether drag.
In 1846,
George Gabriel Stokes
Sir George Gabriel Stokes, 1st Baronet, (; 13 August 1819 – 1 February 1903) was an Irish migration to Great Britain, Irish English physicist and mathematician. Born in County Sligo, Ireland, Stokes spent all of his career at the University ...
pointed out that there was no need to divide the aether inside a moving object into two portions; all of it could be considered as moving at a common velocity. Then, if the aether was conserved while its density changed in proportion to
, the resulting velocity of the aether inside the object was equal to Fresnel's additional velocity component.
Dispersion
The analogy between light waves and transverse waves in elastic solids does not predict ''
dispersion
Dispersion may refer to:
Economics and finance
*Dispersion (finance), a measure for the statistical distribution of portfolio returns
*Price dispersion, a variation in prices across sellers of the same item
*Wage dispersion, the amount of variatio ...
'' — that is, the frequency-dependence of the speed of propagation, which enables
prisms to produce spectra and causes lenses to suffer from
chromatic aberration
In optics, chromatic aberration (CA), also called chromatic distortion and spherochromatism, is a failure of a lens to focus all colors to the same point. It is caused by dispersion: the refractive index of the lens elements varies with the wave ...
. Fresnel, in ''De la Lumière'' and in the second supplement to his first memoir on double refraction, suggested that dispersion could be accounted for if the particles of the medium exerted forces on each other over distances that were significant fractions of a wavelength. Later, more than once, Fresnel referred to the demonstration of this result as being contained in a note appended to his "second memoir" on double refraction. No such note appeared in print, and the relevant manuscripts found after his death showed only that, around 1824, he was comparing refractive indices (measured by Fraunhofer) with a theoretical formula, the meaning of which was not fully explained.
In the 1830s, Fresnel's suggestion was taken up by Cauchy,
Baden Powell, and
Philip Kelland
Philip Kelland PRSE FRS (17 October 1808 – 8 May 1879) was an English mathematician. He was known mainly for his great influence on the development of education in Scotland.
Life
Kelland was born in 1808 the son of Philip Kelland (d.1847), ...
, and it was found to be tolerably consistent with the variation of refractive indices with wavelength over the
visible spectrum
The visible spectrum is the portion of the electromagnetic spectrum that is visual perception, visible to the human eye. Electromagnetic radiation in this range of wavelengths is called ''visible light'' or simply light. A typical human eye wil ...
for a variety of transparent media . These investigations were enough to show that the wave theory was at least compatible with dispersion; if the model of dispersion was to be accurate over a wider range of frequencies, it needed to be modified so as to take account of resonances within the medium .
Conical refraction
The analytical complexity of Fresnel's derivation of the ray-velocity surface was an implicit challenge to find a shorter path to the result. This was answered by MacCullagh in 1830, and by
William Rowan Hamilton
Sir William Rowan Hamilton Doctor of Law, LL.D, Doctor of Civil Law, DCL, Royal Irish Academy, MRIA, Royal Astronomical Society#Fellow, FRAS (3/4 August 1805 – 2 September 1865) was an Irish mathematician, astronomer, and physicist. He was the ...
in 1832.
Hamilton went further, establishing two properties of the surface that Fresnel, in the short time given to him, had overlooked: (i) at each of the four points where the inner and outer sheets of the surface make contact, the surface has a tangent cone (tangential to both sheets), hence a cone of normals, indicating that a cone of wave-normal directions corresponds to a single ray-velocity vector; and (ii) around each of these points, the outer sheet has a circle of contact with a tangent plane, indicating that a cone of ray directions corresponds to a single wave-normal velocity vector. As Hamilton noted, these properties respectively imply that (i) a narrow beam propagating inside the crystal in the direction of the single ray velocity will, on exiting the crystal through a flat surface, break into a hollow cone (''external conical refraction''), and (ii) a narrow beam striking a flat surface of the crystal in the appropriate direction (corresponding to that of the single internal wave-normal velocity) will, on entering the crystal, break into a hollow cone (''internal conical refraction'').
Thus a new pair of phenomena, ''qualitatively'' different from anything previously observed or suspected, had been predicted by mathematics as consequences of Fresnel's theory. The prompt experimental confirmation of those predictions by
Humphrey Lloyd brought Hamilton a prize that had never come to Fresnel: immediate fame.
Legacy
![Cordouan6](https://upload.wikimedia.org/wikipedia/commons/5/5f/Cordouan6.jpg)
Within a century of Fresnel's initial stepped-lens proposal, more than 10,000 lights with Fresnel lenses were protecting lives and property around the world. Concerning the other benefits, the science historian Theresa H. Levitt has remarked:
In the history of physical optics, Fresnel's successful revival of the wave theory nominates him as the pivotal figure between Newton, who held that light consisted of corpuscles, and
James Clerk Maxwell
James Clerk Maxwell (13 June 1831 – 5 November 1879) was a Scottish mathematician and scientist responsible for the classical theory of electromagnetic radiation, which was the first theory to describe electricity, magnetism and ligh ...
, who established that light waves are electromagnetic. Whereas
Albert Einstein
Albert Einstein ( ; ; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist, widely acknowledged to be one of the greatest and most influential physicists of all time. Einstein is best known for developing the theory ...
described Maxwell's work as "the most profound and the most fruitful that physics has experienced since the time of Newton," commentators of the era between Fresnel and Maxwell made similarly strong statements about Fresnel:
* MacCullagh, as early as 1830, wrote that Fresnel's mechanical theory of double refraction "would do honour to the sagacity of Newton".
* Lloyd, in his ''Report on the progress and present state of physical optics'' (1834) for the
British Association for the Advancement of Science
The British Science Association (BSA) is a charity and learned society founded in 1831 to aid in the promotion and development of science. Until 2009 it was known as the British Association for the Advancement of Science (BA). The current Chie ...
, surveyed previous knowledge of double refraction and declared:
The theory of Fresnel to which I now proceed,— and which not only embraces all the known phenomena, but has even outstripped observation, and predicted consequences which were afterwards fully verified,— will, I am persuaded, be regarded as the finest generalization in physical science which has been made since the discovery of universal gravitation.
In 1841, Lloyd published his ''Lectures on the Wave-theory of Light'', in which he described Fresnel's transverse-wave theory as "the noblest fabric which has ever adorned the domain of physical science, Newton's system of the universe alone excepted."
*
William Whewell
William Whewell ( ; 24 May 17946 March 1866) was an English polymath, scientist, Anglican priest, philosopher, theologian, and historian of science. He was Master of Trinity College, Cambridge. In his time as a student there, he achieved dist ...
, in all three editions of his ''History of the Inductive Sciences'' (1837, 1847, and 1857), at the end of Book , compared the histories of physical astronomy and physical optics and concluded:
It would, perhaps, be too fanciful to attempt to establish a parallelism between the prominent persons who figure in these two histories. If we were to do this, we must consider Huyghens and Hooke Hooke may refer to:
* Hooke, Dorset, England
** River Hooke, nearby watercourse
* Robert Hooke (1635–1703), English natural philosopher who discovered Hooke's law
* Hooke (surname), a surname
* Hooke (lunar crater)
* Hooke (Martian crater)
* ...
as standing in the place of Copernicus
Nicolaus Copernicus (; pl, Mikołaj Kopernik; gml, Niklas Koppernigk, german: Nikolaus Kopernikus; 19 February 1473 – 24 May 1543) was a Renaissance polymath, active as a mathematician, astronomer, and Catholic canon, who formulated ...
, since, like him, they announced the true theory, but left it to a future age to give it development and mechanical confirmation; Malus
''Malus'' ( or ) is a genus of about 30–55 species of small deciduous trees or shrubs in the family Rosaceae, including the domesticated orchard apple, crab apples, wild apples, and rainberries.
The genus is native to the temperate zone of th ...
and Brewster, grouping them together, correspond to Tycho Brahe
Tycho Brahe ( ; born Tyge Ottesen Brahe; generally called Tycho (14 December 154624 October 1601) was a Danish astronomer, known for his comprehensive astronomical observations, generally considered to be the most accurate of his time. He was k ...
and Kepler
Johannes Kepler (; ; 27 December 1571 – 15 November 1630) was a German astronomer, mathematician, astrologer, natural philosopher and writer on music. He is a key figure in the 17th-century Scientific Revolution, best known for his laws o ...
, laborious in accumulating observations, inventive and happy in discovering laws of phenomena; and Young and Fresnel combined, make up the Newton of optical science.[Whewell, 1857, pp. 370–71.]
What Whewell called the "true theory" has since undergone two major revisions. The first, by Maxwell, specified the physical fields whose variations constitute the waves of light. Without the benefit of this knowledge, Fresnel managed to construct the world's first coherent theory of light, showing in retrospect that his methods are applicable to multiple types of waves. The second revision, initiated by Einstein's explanation of the
photoelectric effect
The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. Electrons emitted in this manner are called photoelectrons. The phenomenon is studied in condensed matter physics, and solid st ...
, supposed that the energy of light waves was divided into
quanta, which were eventually identified with particles called
photon
A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless, so they always ...
s. But photons did not exactly correspond to Newton's corpuscles; for example, Newton's explanation of ordinary refraction required the corpuscles to travel faster in media of higher refractive index, which photons do not. Neither did photons displace waves; rather, they led to the paradox of
wave–particle duality
Wave–particle duality is the concept in quantum mechanics that every particle or quantum entity may be described as either a particle or a wave. It expresses the inability of the classical concepts "particle" or "wave" to fully describe the ...
. Moreover, the phenomena studied by Fresnel, which included nearly all the optical phenomena known at his time, are still most easily explained in terms of the ''wave'' nature of light. So it was that, as late as 1927, the astronomer
Eugène Michel Antoniadi
Eugène Michel Antoniadi (Greek: Ευγένιος Αντωνιάδης; 1 March 1870 – 10 February 1944) was a Greek- French astronomer.
Biography
Antoniadi was born in Istanbul (Constantinople) but spent most of his adult life in Franc ...
declared Fresnel to be "the dominant figure in optics."
See also
Explanatory notes
References
Citations
Bibliography
* D.F.J. Arago (tr. B. Powell), 1857, "Fresnel" (elegy read at the Public Meeting of the Academy of Sciences, 26 July 1830), in D.F.J. Arago (tr. W.H. Smyth, B. Powell, and R. Grant), ''Biographies of Distinguished Scientific Men'' (single-volume edition), London: Longman, Brown, Green, Longmans, & Roberts, 1857
pp. 399–471 (On the translator's identity, see pp. 425n,452n.) ''Erratum'': In the translator's note on p. 413, a plane tangent to the outer sphere at point ''t'' should intersect the refractive surface (assumed flat); then, ''through that intersection'', tangent planes should be drawn to the inner sphere and spheroid (cf. Mach, 1926, p.263).
* D.F.J. Arago and A. Fresnel, 1819, "Mémoire sur l'action que les rayons de lumière polarisée exercent les uns sur les autres", ''Annales de Chimie et de Physique'', Ser.2, vol. 10, pp. 288–305, March 1819; reprinted in Fresnel, 1866–70, vol. 1
pp. 509–22 translated a
"On the action of rays of polarized light upon each other" in Crew, 1900, pp. 145–55.
* G.-A. Boutry, 1948, "Augustin Fresnel: His time, life and work, 1788–1827", ''Science Progress'', vol. 36, no. 144 (October 1948), pp. 587–604
jstor.org/stable/43413515
* J.Z. Buchwald, 1989,
The Rise of the Wave Theory of Light: Optical Theory and Experiment in the Early Nineteenth Century', University of Chicago Press, .
* J.Z. Buchwald, 2013, "Optics in the Nineteenth Century", in J.Z. Buchwald and R. Fox (eds.), ''The Oxford Handbook of the History of Physics'', Oxford, , pp. 445–72.
* H. Crew (ed.), 1900
''The Wave Theory of Light: Memoirs by Huygens, Young and Fresnel'' American Book Company.
* O. Darrigol, 2012, ''A History of Optics: From Greek Antiquity to the Nineteenth Century'', Oxford, .
* J. Elton, 2009, "A Light to Lighten our Darkness: Lighthouse Optics and the Later Development of Fresnel's Revolutionary Refracting Lens 1780–1900", ''International Journal for the History of Engineering & Technology'', vol. 79, no. 2 (July 2009), pp. 183–244; .
* E. Frankel, 1974, "The search for a corpuscular theory of double refraction: Malus, Laplace and the competition of 1808", ''Centaurus'', vol. 18, no. 3 (September 1974), pp. 223–245.
* E. Frankel, 1976, "Corpuscular optics and the wave theory of light: The science and politics of a revolution in physics", ''Social Studies of Science'', vol. 6, no. 2 (May 1976), pp. 141–84
jstor.org/stable/284930
* A. Fresnel, 1815a, Letter to Jean François "Léonor" Mérimée, 10 February 1815 (Smithsonian Dibner Library, MSS 546A), printed in G. Magalhães, "Remarks on a new autograph letter from Augustin Fresnel: Light aberration and wave theory", ''Science in Context'', vol. 19, no.2 (June 2006), pp. 295–307, , at p.306 (original French) and p.307 (English translation).
* A. Fresnel, 1816, "Mémoire sur la diffraction de la lumière" ("Memoir on the diffraction of light"), ''Annales de Chimie et de Physique'', Ser.2, vol. 1, pp. 239–81 (March 1816); reprinted as "Deuxième Mémoire…" ("Second Memoir…") in Fresnel, 1866–70, vol. 1, pp. 89–122. ''Not'' to be confused with the later "prize memoir" (Fresnel, 1818b).
* A. Fresnel, 1818a, "Mémoire sur les couleurs développées dans les fluides homogènes par la lumière polarisée", read 30 March 1818 (according to Kipnis, 1991, p. 217), published 1846; reprinted in Fresnel, 1866–70, vol. 1
pp. 655–83 translated by E. Ronalds & H. Lloyd a
"Memoir upon the colours produced in homogeneous fluids by polarized light" in Taylor, 1852, pp. 44–65. (Cited page numbers refer to the translation.)
* A. Fresnel, 1818b, "Mémoire sur la diffraction de la lumière" ("Memoir on the diffraction of light"), deposited 29 July 1818, "crowned" 15 March 1819, published (with appended notes) in ''Mémoires de l'Académie Royale des Sciences de l'Institut de France'', vol. (for 1821 & 1822, printed 1826)
pp. 339–475 reprinted (with notes) in Fresnel, 1866–70, vol. 1
pp. 247–383 partly translated a
"Fresnel's prize memoir on the diffraction of light" in Crew, 1900, pp. 81–144. ''Not'' to be confused with the earlier memoir with the same French title (Fresnel, 1816).
* A. Fresnel, 1818c, "Lettre de M. Fresnel à M. Arago sur l'influence du mouvement terrestre dans quelques phénomènes d'optique", ''Annales de Chimie et de Physique'', Ser.2, vol. 9, pp. 57–66 & plate after p.111 (Sep. 1818), & p.286–7 (Nov. 1818); reprinted in Fresnel, 1866–70, vol. 2
pp. 627–36 translated a
"Letter from Augustin Fresnel to François Arago, on the influence of the movement of the earth on some phenomena of optics"in K.F. Schaffner, ''Nineteenth-Century Aether Theories'', Pergamon, 1972 (), pp. 125–35; also translated (with several errors) by R.R. Traill as "Letter from Augustin Fresnel to François Arago concerning the influence of terrestrial movement on several optical phenomena", ''General Science Journal'', 23 January 2006
PDF, 8pp..
* A. Fresnel, 1821a, "Note sur le calcul des teintes que la polarisation développe dans les lames cristallisées" et seq., ''Annales de Chimie et de Physique'', Ser.2, vol. 17, pp. 102–11 (May 1821), 167–96 (June 1821), 312–15 ("Postscript", July 1821); reprinted (with added section nos.) in Fresnel, 1866–70, vol. 1, pp. 609–48; translated as "On the calculation of the tints that polarization develops in crystalline plates, & postscript", / , 2021.
* A. Fresnel, 1821b, "Note sur les remarques de M. Biot...", ''Annales de Chimie et de Physique'', Ser.2, vol. 17, pp. 393–403 (August 1821); reprinted (with added section nos.) in Fresnel, 1866–70, vol. 1, pp. 601–608; translated as "Note on the remarks of Mr. Biot relating to colors of thin plates", / , 2021.
* A. Fresnel, 1821c, Letter to D.F.J.Arago, 21 September 1821, in Fresnel, 1866–70, vol. 2, pp. 257–9; translated a
"Letter to Arago on biaxial birefringence" ''Wikisource'', April 2021.
* A. Fresnel, 1822a, ''De la Lumière'' (''On Light''), in J. Riffault (ed.)
''Supplément à la traduction française de la cinquième édition du "Système de Chimie" par Th.Thomson'' Paris: Chez Méquignon-Marvis, 1822, pp. 1–137,535–9; reprinted in Fresnel, 1866–70, vol. 2, pp. 3–146; translated by T. Young as "Elementary view of the undulatory theory of light", ''Quarterly Journal of Science, Literature, and Art'', vol. 22 (Jan.–Jun.1827), pp.&nbs
127–41441–54 vol. 23 (Jul.–Dec.1827), pp.&nbs
113–35431–48 vol. 24 (Jan.–Jun.1828), pp.&nbs
198–215 vol. 25 (Jul.–Dec.1828), pp.&nbs
168–91389–407 vol. 26 (Jan.–Jun.1829), pp.&nbs
159–65
* A. Fresnel, 1822b, "Mémoire sur un nouveau système d'éclairage des phares", read 29 July 1822; reprinted in Fresnel, 1866–70, vol. 3
pp. 97–126 translated by T. Tag a
"Memoir upon a new system of lighthouse illumination" U.S. Lighthouse Society, accessed 26 August 2017
archived19 August 2016. (Cited page numbers refer to the translation.)
* A. Fresnel, 1827, "Mémoire sur la double réfraction", ''Mémoires de l'Académie Royale des Sciences de l'Institut de France'', vol. (for 1824, printed 1827)
pp. 45–176 reprinted as "Second mémoire…" in Fresnel, 1866–70, vol. 2
pp. 479–596 translated by A.W. Hobson a
"Memoir on double refraction" in Taylor, 1852, pp. 238–333. (Cited page numbers refer to the translation. For notable errata in the original edition, and consequently in the translation, see Fresnel, 1866–70, vol. 2, p. 596n.)
* A. Fresnel (ed. H. de Sénarmont, E. Verdet, and L. Fresnel), 1866–70, ''Oeuvres complètes d'Augustin Fresnel'' (3 volumes), Paris: Imprimerie Impériale
vol. 1 (1866)vol. 2 (1868)vol. 3 (1870)
* I. Grattan-Guinness, 1990, ''Convolutions in French Mathematics, 1800–1840'', Basel: Birkhäuser, vol. 2, , chapter 13 (pp. 852–915, "The entry of Fresnel: Physical optics, 1815–1824") and chapter 15 (pp. 968–1045, "The entry of Navier and the triumph of Cauchy: Elasticity theory, 1819–1830").
* C. Huygens, 1690, ''Traité de la Lumière'' (Leiden: Van der Aa), translated by S.P. Thompson as
Treatise on Light', University of Chicago Press, 1912; Project Gutenberg, 2005. (Cited page numbers match the 1912 edition and the Gutenberg HTML edition.)
* F.A. Jenkins and H.E. White, 1976, ''Fundamentals of Optics'', 4th Ed., New York: McGraw-Hill, .
* N. Kipnis, 1991, ''History of the Principle of Interference of Light'', Basel: Birkhäuser, , chapters .
* K.A. Kneller (tr. T.M. Kettle), 1911, ''Christianity and the Leaders of Modern Science: A contribution to the history of culture in the nineteenth century'', Freiburg im Breisgau: B. Herder
pp. 146–9
* T.H. Levitt, 2009, ''The Shadow of Enlightenment: Optical and Political Transparency in France, 1789–1848'', Oxford, .
* T.H. Levitt, 2013, ''A Short Bright Flash: Augustin Fresnel and the Birth of the Modern Lighthouse'', New York: W.W. Norton, .
* H. Lloyd, 1834
"Report on the progress and present state of physical optics" ''Report of the Fourth Meeting of the British Association for the Advancement of Science'' (held at Edinburgh in 1834), London: J. Murray, 1835, pp. 295–413.
* E. Mach (tr. J.S. Anderson & A.F.A. Young), ''The Principles of Physical Optics: An Historical and Philosophical Treatment'', London: Methuen & Co., 1926.
* I. Newton, 1730
''Opticks: or, a Treatise of the Reflections, Refractions, Inflections, and Colours of Light'' 4th Ed. (London: William Innys, 1730; Project Gutenberg, 2010); republished with Foreword by A. Einstein and Introduction by E.T. Whittaker (London: George Bell & Sons, 1931); reprinted with additional Preface by I.B. Cohen and Analytical Table of Contents by D.H.D. Roller, Mineola, NY: Dover, 1952, 1979 (with revised preface), 2012. (Cited page numbers match the Gutenberg HTML edition and the Dover editions.)
* R.H. Silliman, 1967, ''Augustin Fresnel (1788–1827) and the Establishment of the Wave Theory of Light'' (PhD dissertation, ), Princeton University, submitted 1967, accepted 1968; available from ProQuest (missing the first page of the preface).
* R.H. Silliman, 2008, "Fresnel, Augustin Jean", ''Complete Dictionary of Scientific Biography'', Detroit: Charles Scribner's Sons, vol. 5, pp. 165–71. (Th
version at ''encyclopedia.com''lacks the diagram and equations.)
* R. Taylor (ed.), 1852, ''Scientific Memoirs, selected from the Transactions of Foreign Academies of Science and Learned Societies, and from Foreign Journals'' (in English)
vol. London: Taylor & Francis.
* W. Whewell, 1857, ''History of the Inductive Sciences: From the Earliest to the Present Time'', 3rd Ed., London: J.W. Parker & Son
vol. 2 book , chapters .
*
E. T. Whittaker
Sir Edmund Taylor Whittaker (24 October 1873 – 24 March 1956) was a British mathematician, physicist, and historian of science. Whittaker was a leading mathematical scholar of the early 20th-century who contributed widely to applied mathema ...
, 1910,
''A History of the Theories of Aether and Electricity: From the age of Descartes to the close of the nineteenth century'', London: Longmans, Green, & Co., chapters .
* J. Worrall, 1989
"Fresnel, Poisson and the white spot: The role of successful predictions in the acceptance of scientific theories" in D. Gooding, T. Pinch, and S. Schaffer (eds.), ''The Uses of Experiment: Studies in the Natural Sciences'', Cambridge University Press, , pp. 135–57.
* T. Young, 1807, ''A Course of Lectures on Natural Philosophy and the Mechanical Arts'' (2 volumes), London: J.Johnson
vol. 1vol. 2
* T. Young (ed. G. Peacock), 1855, ''Miscellaneous Works of the late Thomas Young'', London: J. Murray
vol. 1
Further reading
Some English translations of works by Fresnel are included in the above Bibliography. For a more comprehensive list, see "External links" below.
The most detailed secondary source on Fresnel in English is apparently Buchwald 1989 —in which Fresnel, although not named in the title, is clearly the central character.
On lighthouse lenses, this article heavily cites Levitt 2013, Elton 2009, and Thomas Tag at the U.S. Lighthouse Society (see "External links" below). All three authors deal not only with Fresnel's contributions but also with later innovations that are not mentioned here (see ''
Fresnel lens: History'').
By comparison with the volume and impact of his scientific and technical writings, biographical information on Fresnel is remarkably scarce. There is no book-length critical biography of him, and anyone who proposes to write one must confront the fact that the letters published in his ''Oeuvres complètes''—contrary to the title—are heavily redacted. In the words of Robert H. Silliman (1967, p. 6n): "By an unhappy judgment of the editors, dictated in part, one suspects, by political expediency, the letters appear in fragmentary form, preserving almost nothing beyond the technical discussions of Fresnel and his correspondents." It is not clear from the secondary sources whether the manuscripts of those letters are still extant (cf. Grattan-Guinness, 1990, p.854n).
External links
*
List of English translations of works by Augustin Fresnelat
Zenodo
Zenodo is a general-purpose open repository developed under the European OpenAIRE program and operated by CERN.
It allows researchers to deposit research papers, data sets, research software, reports, and any other research related digital artef ...
.
United States Lighthouse Society especially
Fresnel Lenses.
* .
* .
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