History of metamaterials
   HOME

TheInfoList



OR:

The history of metamaterials begins with
artificial dielectrics Artificial dielectrics are fabricated composite materials, often consisting of arrays of conductive shapes or particles in a nonconductive support matrix, designed to have specific electromagnetic properties similar to dielectrics. As long as the ...
in
microwave engineering Microwave engineering pertains to the study and design of microwave circuits, components, and systems. Fundamental principles are applied to analysis, design and measurement techniques in this field. The short wavelengths involved distinguish this ...
as it developed just after
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...
. Yet, there are seminal explorations of artificial materials for manipulating
electromagnetic wave In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visib ...
s at the end of the 19th century. Hence, the history of metamaterials is essentially a history of developing certain types of manufactured materials, which interact at
radio frequency Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the ...
,
microwave Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ra ...
, and later optical frequencies. As the science of materials has advanced, photonic materials have been developed which use the
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 a ...
of
light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 te ...
as the fundamental carrier of information. This has led to
photonic crystal A photonic crystal is an optical nanostructure in which the refractive index changes periodically. This affects the propagation of light in the same way that the structure of natural crystals gives rise to X-ray diffraction and that the atomic ...
s, and at the beginning of the new millennium, the
proof of principle Proof of concept (POC or PoC), also known as proof of principle, is a realization of a certain method or idea in order to demonstrate its feasibility, or a demonstration in principle with the aim of verifying that some concept or theory has prac ...
for functioning
metamaterials A metamaterial (from the Greek word μετά ''meta'', meaning "beyond" or "after", and the Latin word ''materia'', meaning "matter" or "material") is any material engineered to have a property that is not found in naturally occurring materials. ...
with a negative index of refraction in the
microwave Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ra ...
- (at 10.5
Gigahertz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one he ...
) and optical range. This was followed by the first proof of principle for
metamaterial cloaking Metamaterial cloaking is the usage of metamaterials in an invisibility cloak. This is accomplished by manipulating the paths traversed by light through a novel optical material. Metamaterials direct and control the propagation and transmission o ...
(shielding an object from view), also in the microwave range, about six years later. However, a cloak that can conceal objects across the entire
electromagnetic spectrum The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The electromagnetic spectrum covers electromagnetic waves with frequencies ranging fro ...
is still decades away. Many
physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...
and
engineering Engineering is the use of scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad range of more speciali ...
problems need to be solved. Nevertheless,
negative refractive materials Negative-index metamaterial or negative-index material (NIM) is a metamaterial whose refractive index for an electromagnetic wave has a negative value over some frequency range. NIMs are constructed of periodic basic parts called unit cells, whi ...
have led to the development of
metamaterial antennas Metamaterial antennas are a class of antennas which use metamaterials to increase performance of miniaturized ( electrically small) antenna systems. Their purpose, as with any electromagnetic antenna, is to launch energy into free space. However, ...
and metamaterial microwave lenses for miniature wireless system antennas which are more efficient than their conventional counterparts. Also, metamaterial antennas are now commercially available. Meanwhile, subwavelength focusing with the
superlens A superlens, or super lens, is a lens which uses metamaterials to go beyond the diffraction limit. For example, in 1995, Guerra combined a transparent grating having 50nm lines and spaces (the "metamaterial") with a conventional microscope immersio ...
is also a part of present-day metamaterials research.


Early wave studies

Classical waves transfer
energy In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of hea ...
without transporting
matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic part ...
through the medium (material). For example, waves in a pond do not carry the water molecules from place to place; rather the wave's energy travels through the water, leaving the water molecules in place. Additionally, charged particles, such as
electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no ...
s and protons create electromagnetic fields when they move, and these fields transport the type of energy known as electromagnetic radiation, or light. A changing magnetic field will induce a changing electric field and vice versa—the two are linked. These changing fields form electromagnetic waves. Electromagnetic waves differ from mechanical waves in that they do not require a medium to propagate. This means that electromagnetic waves can travel not only through air and solid materials, but also through the vacuum of space. The "''history of metamaterials''" can have a variety starting points depending on the properties of interest. Related early wave studies started in 1904 and progressed through more than half of the first part of the twentieth century. This early research included the relationship of the phase velocity to group velocity and the relationship of the
wave vector In physics, a wave vector (or wavevector) is a vector used in describing a wave, with a typical unit being cycle per metre. It has a magnitude and direction. Its magnitude is the wavenumber of the wave (inversely proportional to the wavelength), ...
and Pointing vector. In 1904 the possibility of negative phase velocity accompanied by an anti-parallel group velocity were noted by
Horace Lamb Sir Horace Lamb (27 November 1849 – 4 December 1934)R. B. Potts,, ''Australian Dictionary of Biography'', Volume 5, MUP, 1974, pp 54–55. Retrieved 5 Sep 2009 was a British applied mathematician and author of several influential texts on ...
(book: ''Hydrodynamics'') and
Arthur Schuster Sir Franz Arthur Friedrich Schuster (12 September 1851 – 14 October 1934) was a German-born British physicist known for his work in spectroscopy, electrochemistry, optics, X-radiography and the application of harmonic analysis to physics. ...
(Book: ''Intro to Optics'').Slyusar V.I. Metamaterials on antenna solutions.// 7th International Conference on Antenna Theory and Techniques ICATT’09, Lviv, Ukraine, October 6–9, 2009. pp. 19–2

/ref> However both thought practical achievement of these phenomena were not possible. In 1945 Leonid Mandelstam (also "Mandel'shtam") studied the anti-parallel phase and group advance in more detail. He is also noted for examining the electromagnetic characteristics of materials demonstrating negative refraction, as well as the first left-handed material concept. These studies included negative group velocity. He reported that such phenomena occurs in a crystal lattice. This may be considered significant because the metamaterial is a man made crystal lattice (structure). (PDF is self-published version.)Early wave studies * H. Lamb, "On group-velocity," Proc. Lond. Math. Soc., vol. 1, pp. 473–79, 1904. * A. Schuster
An Introduction to the Theory of Optics
pp. 313–18; London: Edward Arnold, 1904. Archived in public domain and the online full text is linked to the Internet Archive. The Public domain full Text 1909 edition is her

* L.I. Mandel'shtam
"Group velocity in a crystal lattice"
Zh. Eksp. Teor. Fiz., Vol. 15 (1945), pp. 475–78 * L.I. Mandelstam, The 4th Lecture of L.I. Mandelstam given at Moscow State University (05/05/1944), Collection of Scientific Works, Vol. 2 (1994) Nauka, Moscow (in Russian). * V.E. Pafomov, Sov. Phys. JETP 36 1321 (1959).
Transition radiation and Cerenkenov radiation
* V.G. Veselago, "The electrodynamics of substances with simultaneously negative values of ε and μ," Soviet Physics Uspekhi, vol. 10, no. 4, pp. 509–14, January–February 1968
In 1905 H.C. Pocklington also studied certain effects related to negative group velocity. V.E. Pafomov (1959), and several years later, the research team V.M. Agranovich and V.L. Ginzburg (1966) reported the repercussions of negative
permittivity In electromagnetism, the absolute permittivity, often simply called permittivity and denoted by the Greek letter ''ε'' (epsilon), is a measure of the electric polarizability of a dielectric. A material with high permittivity polarizes more in ...
, negative permeability, and negative group velocity in their study of crystals and excitons. In 1967, V.G. Veselago from
Moscow Institute of Physics and Technology Moscow Institute of Physics and Technology (MIPT; russian: Московский Физико-Технический институт, also known as PhysTech), is a public research university located in Moscow Oblast, Russia. It prepares speciali ...
considered the theoretical model of medium that known now as a metamaterial. However, physical experimentation did not occur until 33 years after the paper's publication due to lack of available materials and lack of sufficient computing power. It was not until the 1990s that materials and computing power became available to artificially produce the necessary structures. Veselago also predicted a number of electromagnetic phenomena that would be reversed including the
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 ...
. In addition, he is credited with coining the term "left handed material" for the present day metamaterial because of the anti-parallel behavior of the
wave vector In physics, a wave vector (or wavevector) is a vector used in describing a wave, with a typical unit being cycle per metre. It has a magnitude and direction. Its magnitude is the wavenumber of the wave (inversely proportional to the wavelength), ...
and other electromagnetic fields. Moreover, he noted that the material he was studying was a double negative material, as certain metamaterials are named today, because of the ability to simultaneously produce negative values for two important parameters, e.g. permittivity and permeability. In 1968, his paper was translated and published in English.He is often credited with inventing the modern day electromagnetic metamaterials as a result of his seminal 1967/68 report. He was nominated later for a Nobel prize. Later still, developments in
nanofabrication Nanolithography (NL) is a growing field of techniques within nanotechnology dealing with the engineering (patterning e.g. etching, depositing, writing, printing etc) of nanometer-scale structures on various materials. The modern term reflects on a ...
and subwavelength imaging techniques are now taking this work into optical
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, t ...
s.Shalaev, V.M. "Optical negative-index metamaterials,"
Nature Photonics ''Nature Photonics'' is a peer-reviewed scientific journal published by the Nature Publishing Group. The editor-in-chief is Oliver Graydon. The journal covers research related to optoelectronics, laser science, imaging, communications, and other ...
Vol. 1, 41–48 (2007) Novel materials and engineered structures


Early electromagnetic media

In the 19th century
Maxwell's equations Maxwell's equations, or Maxwell–Heaviside equations, are a set of coupled partial differential equations that, together with the Lorentz force law, form the foundation of classical electromagnetism, classical optics, and electric circuits. ...
united all previous observations, experiments, and established propositions pertaining to
electricity Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as describ ...
and magnetism into a consistent theory, which is also fundamental to
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, ultrav ...
. Maxwell's work demonstrated that electricity, magnetism and even light are all manifestations of the same phenomenon, namely the electromagnetic field. Likewise, the concept of using certain constructed materials as a method for manipulating
electromagnetic wave In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visib ...
s dates back to the 19th century. Microwave theory had developed significantly during the latter part of the 19th century with the cylindrical
parabolic reflector A parabolic (or paraboloid or paraboloidal) reflector (or dish or mirror) is a reflective surface used to collect or project energy such as light, sound, or radio waves. Its shape is part of a circular paraboloid, that is, the surface gener ...
,
dielectric lens A Luneburg lens (original German ''Lüneburg lens'', sometimes incorrectly spelled ''Luneberg lens'') is a spherically symmetric gradient-index lens. A typical Luneburg lens's refractive index ''n'' decreases radially from the center to the outer ...
, microwave absorbers, the cavity radiator, the radiating iris, and the pyramidal electromagnetic horn. The science involving microwaves also included round, square, and rectangular
waveguides A waveguide is a structure that guides waves, such as electromagnetic waves or sound, with minimal loss of energy by restricting the transmission of energy to one direction. Without the physical constraint of a waveguide, wave intensities de ...
precluding Sir Rayleigh's published work on waveguide operation in 1896. Microwave optics, involving the focusing of microwaves, introduced quasi-optical components, and a treatment of microwave optics was published in 1897 (by Righi). A facility of the NSF provides added material to the original paper
The work of Jagadish Chandra Bose: 100 years of millimeter wave research


Jagadish Chandra Bose

Jagadish Chandra Bose was a scientist involved in original microwave research during the 1890s. As officiating professor of physics at Presidency College he involved himself with laboratory experiments and studies involving
refraction In physics, refraction is the redirection of a wave as it passes from one medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commonly observed phenome ...
, diffraction and polarization, as well as
transmitter In electronics and telecommunications, a radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. The transmitter itself generates a radio frequency alternating current, which is applied to the ...
s, receivers and various microwave components. He connected receivers to a sensitive
galvanometer A galvanometer is an electromechanical measuring instrument for electric current. Early galvanometers were uncalibrated, but improved versions, called ammeters, were calibrated and could measure the flow of current more precisely. A galvan ...
, and developed
crystals A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...
to be used as a receiver. The crystals operated in the shortwave radio range. Crystals were also developed to detect both
white White is the lightest color and is achromatic (having no hue). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully reflect and scatter all the visible wavelengths of light. White o ...
and
ultraviolet light Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...
. These crystals were patented in 1904 for their capability to detect
electromagnetic radiation In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visible) li ...
. Furthermore, it appears that his work also anticipated the existence of p-type and n-type semiconductors by 60 years. For the general public in 1895, Bose was able to remotely ring a bell and explode gunpowder with the use of electromagnetic waves. In 1896, it was reported that Bose had transmitted electromagnetic signals over almost a mile. Microwave Symposium Digest. 1997. IEEE MTT-S International. Issue Date: 8–13 June 1997. pp. 553–556 . *This paper appears in * * In 1897, Bose reported on his microwave research (experiments) at the Royal Institution in London. There he demonstrated his apparatus at
wavelengths 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, tr ...
that ranged from 2.5 centimeters to 5 millimeters.


Early chiral media

In 1898, Jagadish Chandra Bose conducted the first
microwave Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ra ...
experiment on twisted structures. These twisted structures match the geometries that are known as artificial chiral media in today's terminology. By this time, he had also researched
double refraction 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 ...
(birefringence) in crystals. Other research included polarization of electric field "waves" that crystals produce. He discovered this type of polarization in other materials including a class of
dielectric In electromagnetism, a dielectric (or dielectric medium) is an electrical insulator that can be polarised by an applied electric field. When a dielectric material is placed in an electric field, electric charges do not flow through the mate ...
s. In addition, chirality as optical activity in a given material is a phenomenon that has been studied since the 19th century. By 1811, a study 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 ...
crystals revealed that such
crystalline solid A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...
s rotate the polarization of polarized light denoting optical activity. By 1815, materials other than crystals, such as oil of turpentine were known to exhibit chirality. However, the basic cause was not known. Louis Pasteur solved the problem (chirality of the molecules) originating a new discipline known as stereochemistry. At the
macroscopic The macroscopic scale is the length scale on which objects or phenomena are large enough to be visible with the naked eye, without magnifying optical instruments. It is the opposite of microscopic. Overview When applied to physical phenomena a ...
scale, Lindman applied microwaves to the problem with wire spirals (wire helices) in 1920 and 1922.(see abstract) Karl F. Lindman, from 1914 and into the 1920s, studied artificial chiral media formed by a collection of randomly oriented small
spirals In mathematics, a spiral is a curve which emanates from a point, moving farther away as it revolves around the point. Helices Two major definitions of "spiral" in the American Heritage Dictionary are: Much of the historic research related to
metamaterial A metamaterial (from the Greek word μετά ''meta'', meaning "beyond" or "after", and the Latin word ''materia'', meaning "matter" or "material") is any material engineered to have a property that is not found in naturally occurring materials. ...
s is weighted from the view of antenna beam shaping within
microwave engineering Microwave engineering pertains to the study and design of microwave circuits, components, and systems. Fundamental principles are applied to analysis, design and measurement techniques in this field. The short wavelengths involved distinguish this ...
just after World War II. Furthermore, metamaterials appear to be historically linked to the body of research pertaining to
artificial dielectrics Artificial dielectrics are fabricated composite materials, often consisting of arrays of conductive shapes or particles in a nonconductive support matrix, designed to have specific electromagnetic properties similar to dielectrics. As long as the ...
throughout the late 1940s, the 1950s and the 1960s. The most common use for artificial dielectrics throughout prior decades has been in the
microwave Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ra ...
regime for antenna beam shaping. The artificial dielectrics had been proposed as a low cost and lightweight "tool". Research on artificial dielectrics, other than metamaterials, is still ongoing for pertinent parts of the electromagnetic spectrum. Pioneering works in microwave engineering on artificial dielectrics in microwave were produced by Winston E. Kock, Seymour Cohn, John Brown, and
Walter Rotman Walter Rotman (August 24, 1922 – May 19, 2007) was an American scientist known for his work in radar and antenna design. Among his inventions were the Rotman lens, the sandwich wire antenna, and the trough waveguide. Biography Walter Rotman was ...
. ''Periodic'' artificial structures were proposed by Kock, Rotman, and
Sergei Schelkunoff Sergei Alexander Schelkunoff (russian: Сергей Александрович Щелкунов; January 27, 1897 – May 2, 1992), who published as S. A. Schelkunoff, was a distinguished mathematician, engineer and electromagnetism theorist who ...
. There is also an extensive reference list that is focused on the properties of artificial dielectrics in the 1990 book, '' Field theory of guided waves'' by R.E. Collin. Schelkunoff achieved notice for contributions to antenna theory and
electromagnetic wave In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visib ...
propagation. * The estimated year of publication (based on this article's references) is 2005. * Quote from abstract: "''The number of proposals for practical microwave and optical applications benefiting from the properties of ovel materialsis increasing rapidly. However, the utilization of artificial materials in microwave engineering is not a new concept. The purpose of this short report is to revisit some of the most important early contributions that have led to the utilization of artificial dielectrics and magnetics in microwave applications.''" "Magnetic particles made of capacitively loaded loops were also suggested by Sergei Schelkunoff in 1952 (who was a senior colleague of Winston Kock at Bell Labs at the time). However, Schelkunoff suggested these particles as a means of synthesizing high permeability (and not negative) values but he recognized that such high permeability artificial dielectrics would be quite dispersive." W.E. Kock proposed metallic and wire lenses for antennas. Some of these are the metallic delay lens, parallel-wire lens, and the wire mesh lens. In addition, he conducted analytical studies regarding the response of customized metallic particles to a quasistatic electromagnetic radiation. As with the current large group of researchers conveying the behavior of metamaterials, Kock noted behaviors and structure in artificial materials that are similar to metamaterials. He employed particles, which would be of varying geometric shape;
sphere A sphere () is a geometrical object that is a three-dimensional analogue to a two-dimensional circle. A sphere is the set of points that are all at the same distance from a given point in three-dimensional space.. That given point is th ...
s, discs,
ellipsoids 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 ...
and
prolate 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 circ ...
or oblate spheroids, and would be either isolated or set in a repeating pattern as part of an array configuration. Furthermore, he was able to determine that such particles behave as a
dielectric In electromagnetism, a dielectric (or dielectric medium) is an electrical insulator that can be polarised by an applied electric field. When a dielectric material is placed in an electric field, electric charges do not flow through the mate ...
medium. He also noticed that the
permittivity In electromagnetism, the absolute permittivity, often simply called permittivity and denoted by the Greek letter ''ε'' (epsilon), is a measure of the electric polarizability of a dielectric. A material with high permittivity polarizes more in ...
"ε" and permeability "μ" of these particles can be purposely tuned, but not independently. With metamaterials, however, local values for both ε and μ are designed as part of the fabrication process, or analytically designed in theoretical studies. Because of this process, individual metamaterial inclusions can be independently tuned. *This page contains the following citations: **W.E. Kock, "''Metal Plate Lenses for Microwaves''", Bell Telephone Lab Report MM-45-160-23, March 1945. **W.E. Kock, "''Wire Lens Antennas''", BTL Report MM-44-160-100, April 1944 *This book was first published in 1949 by McGraw-Hill Book Company Inc. *This section pertains to (1) Wire lenses (2) parallel-wire lens (3) wire-mesh lens and the images are "Courtesy of the Bell Telephone Laboratory." With artificial dielectrics Kock was able to see that any value for permittivity and permeability, arbitrarily large or small, can be achieved, and that this included the possibility of negative values for these parameters. The optical properties of the medium depended solely on the particles’ geometrical shape and spacing, rather than on their own intrinsic behavior. His work also anticipated the
split-ring resonator A split-ring resonator (SRR) is an artificially produced structure common to metamaterials. Its purpose is to produce the desired magnetic susceptibility (magnetic response) in various types of metamaterials up to 200 terahertz. These media cr ...
, a fabricated periodic structure that is a common workhorse for metamaterials. Kock, however, did not investigate the simultaneous occurrence of negative values of ε and μ, which has become one of the first achievements defining modern metamaterials. This was because research in artificial materials was oriented toward other goals, such as creating plasma media at RF or microwave frequencies related to the overarching needs of NASA and the space program at that time. In one journal, entitled ''
Proceedings of the IRE The ''Proceedings of the IEEE'' is a monthly peer-reviewed scientific journal published by the Institute of Electrical and Electronics Engineers (IEEE). The journal focuses on electrical engineering and computer science. According to the ''Journa ...
'' (see ref below), Kock describes a new type of antenna applying the optical properties of Radio waves. It is in fact a metallic lens, which focuses electromagnetic waves "...''from short waves up to wavelengths of perhaps five meters or more''." * * * *Kock, Winston E. and Harvey, F.K. *:
Walter Rotman Walter Rotman (August 24, 1922 – May 19, 2007) was an American scientist known for his work in radar and antenna design. Among his inventions were the Rotman lens, the sandwich wire antenna, and the trough waveguide. Biography Walter Rotman was ...
and R.F. Turner advanced microwave beam shaping systems with a lens that has three perfect focal points; two symmetrically located off-axis and one on-axis. They published the design equations for the improved straight-front-face lens, the evaluation of its phase control capabilities, scanning capabilities, and the demonstrated fabrication techniques applicable to this type of design. . *This section has public domain material obtained from the United States Air Force. Rotman invented other periodic structures that include many types of surface wave antennas: the trough waveguide, the channel waveguide, and the sandwich wire antenna. The sandwich wire antenna, asymmetrical trough waveguide antenna * * * *


Photonic structures

"At frequencies of a few hundred gigahertz and lower, electrons are the principle particles which serve as the workhorse of devices. On the other hand, at
infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
through optical to
ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30  PHz) to 400 nm (750  THz), shorter than that of visible light, but longer than X-rays. UV radiation ...
wavelengths, the photon is the fundamental particle of choice." The word 'photonics' appeared in the late 1960s to describe a research field whose goal was to use light to perform functions that traditionally fell within the typical domain of electronics, such as telecommunications, information processing, among other processes. The term ''photonics'' more specifically connotes: * The particle properties of light, * The potential of creating signal processing device technologies using photons, * The practical application of optics, and * An analogy to
electronics The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons using electronic devices. Electronics uses active devices to control electron flow by amplification ...
. Hence, as photonic materials are used, the photons, rather than electrons, become the fundamental carriers of information. Furthermore, the photon appears to be a more efficient carrier of information, and materials that can process photonic signals are both in use and in further development. Additionally, developing photonic materials will lead to further miniaturization of components. In 1987
Eli Yablonovitch Eli Yablonovitch (born 15 December 1946) is an American physicist and engineer who, along with Sajeev John founded the field of photonic crystals in 1987.M.Kapoor (2013Electromagnetic Band Gap Structures page 58 He and his team were the first t ...
proposed controlling spontaneous emissions and constructing physical zones in periodic dielectrics that forbid certain wavelengths of electromagnetic radiation. These capabilities would be built into three-dimensional periodic dielectric structures (artificial dielectric). He noted that controlling spontaneous emission is desirable for semiconductor processes.


Exceptional phenomena


Invention of the metamaterial

Historically, and conventionally, the function or behavior of materials can be altered through their chemistry. This has long been known. For example, adding
lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...
changes the color or hardness of
glass Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling ( quenching ...
. However, at the end of the 20th century this description was expanded by
John Pendry Sir John Brian Pendry, (born 4 July 1943) is an English theoretical physicist known for his research into refractive indices and creation of the first practical " Invisibility Cloak". He is a professor of theoretical solid state physics at Impe ...
, a
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 cau ...
from Imperial College in
London London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary dow ...
. In the 1990s he was consulting for a British company, ''Marconi Materials Technology'', as a condensed matter physics expert. The company manufactured a stealth technology made of a radiation-absorbing
carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...
that was for
naval vessel A naval ship is a military ship (or sometimes boat, depending on classification) used by a navy. Naval ships are differentiated from civilian ships by construction and purpose. Generally, naval ships are damage resilient and armed with w ...
s. However, the company did not understand the
physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...
of the material. The company asked Pendry if he could understand how the material worked. Pendry discovered that the radiation absorption property did not come from the molecular or
chemical structure A chemical structure determination includes a chemist's specifying the molecular geometry and, when feasible and necessary, the electronic structure of the target molecule or other solid. Molecular geometry refers to the spatial arrangement of ...
of the material, i.e. the carbon per se. This property came from the long and thin, physical shape of the
carbon fiber Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon compo ...
s. He realized rather than conventionally altering a material through its chemistry, as lead does with glass, the behavior of a material can be altered by changing a material's internal structure on a very fine scale. The very fine scale was less than the
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, t ...
of the
electromagnetic radiation In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visible) li ...
that is applied. The theory applies across the electromagnetic spectrum that is in use by today's technologies. The radiations of interest are from radio waves, and microwaves, through infrared to the visible wavelengths. Scientists view this material as "beyond" conventional materials. Hence, the Greek word "meta" was attached, and these are called
metamaterials A metamaterial (from the Greek word μετά ''meta'', meaning "beyond" or "after", and the Latin word ''materia'', meaning "matter" or "material") is any material engineered to have a property that is not found in naturally occurring materials. ...
. After successfully deducing and realizing the carbon fiber structure, Pendry further proposed that he try to change the magnetic properties of a non-magnetic material, also by altering its physical structure. The material would not be intrinsically magnetic, nor inherently susceptible to being magnetized.
Copper wire Copper has been used in electrical wiring since the invention of the electromagnet and the telegraph in the 1820s. The invention of the telephone in 1876 created further demand for copper wire as an electrical conductor. Copper is the electri ...
is such a non-magnetic material. He envisioned fabricating a non-magnetic composite material, which could mimic the movements of electrons orbiting atoms. However, the structures are fabricated on a scale that is magnitudes larger than the atom, yet smaller than the radiated wavelength. He envisioned and hypothesized miniature loops of copper wire set in a
fiberglass Fiberglass (American English) or fibreglass ( Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass clo ...
substrate could mimic the action of electrons but on a larger scale. Furthermore, this
composite material A composite material (also called a composition material or shortened to composite, which is the common name) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or ...
could act like a slab of
iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundanc ...
. In addition, he deduced that a current run through the loops of wire results in a magnetic response. This metamaterial idea resulted in variations. Cutting the loops results in a magnetic resonator, which acts like a switch. The switch, in turn, would allow Pendry to determine or alter the magnetic properties of the material simply by choice. At the time, Pendry didn't realize the significance of the two materials he had engineered. By combining the electrical properties of Marconi's radar-absorbing material with his new man-made magnetic material he had unwittingly placed in his hands a new way to manipulate electromagnetic radiation. In 1999, Pendry published his new conception of artificially produced magnetic materials in a notable physics journal. This was read by scientists all over the world, and it "stoked their imagination".PDF copy


Negative refractive index

In 1967,
Victor Veselago Victor Georgievich Veselago (13 June 1929, Ukraine – 15 September 2018)Snell's law, an extraordinary lens, and other exceptional phenomena can occur within the
laws of physics Scientific laws or laws of science are statements, based on repeated experiments or observations, that describe or predict a range of natural phenomena. The term ''law'' has diverse usage in many cases (approximate, accurate, broad, or narrow) ...
. This theory lay dormant for a few decades. There were no materials available in nature, or otherwise, that could physically realize Veselago's analysis. Not until thirty-three years later did the properties of this material, a
metamaterial A metamaterial (from the Greek word μετά ''meta'', meaning "beyond" or "after", and the Latin word ''materia'', meaning "matter" or "material") is any material engineered to have a property that is not found in naturally occurring materials. ...
, became a subdiscipline of
physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which r ...
and
engineering Engineering is the use of scientific principles to design and build machines, structures, and other items, including bridges, tunnels, roads, vehicles, and buildings. The discipline of engineering encompasses a broad range of more speciali ...
. However, there were certain observations, demonstrations, and implementations that closely preceded this work.
Permittivity In electromagnetism, the absolute permittivity, often simply called permittivity and denoted by the Greek letter ''ε'' (epsilon), is a measure of the electric polarizability of a dielectric. A material with high permittivity polarizes more in ...
of metals, with values that could be stretched from the positive to the negative domain, had been studied extensively. In other words, negative permittivity was a known phenomenon by the time the first metamaterial was produced. Contemporaries of Kock were involved in this type of research. The concentrated effort was led by the US government for researching interactions between the ionosphere and the re-entry of NASA space vehicles. In the 1990s, Pendry et al. developed sequentially repeating thin wire structures, analogous to
crystal structures A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macrosc ...
. These extended the range of material permittivity. However, a more revolutionary structure developed by Pendry et al. was a structure that could control magnetic interactions ( permeability) of the radiated light, albeit only at microwave frequencies. This sequentially repeating, split ring structure, extended material magnetic parameters into the negative. This lattice or periodic, "magnetic" structure was constructed from non-magnetic components. Hence, in electromagnetic domain, a negative value for permittivity and permeability occurring simultaneously was a requirement to produce the first metamaterials. These were beginning steps for proof of principle regarding Veselago's original 1967 proposal. In 2000, a team of
UCSD The University of California, San Diego (UC San Diego or colloquially, UCSD) is a public land-grant research university in San Diego, California. Established in 1960 near the pre-existing Scripps Institution of Oceanography, UC San Diego is t ...
researchers produced and demonstrated metamaterials, which exhibited unusual physical properties that were never before produced in
nature Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are ...
. These materials obey the
laws of physics Scientific laws or laws of science are statements, based on repeated experiments or observations, that describe or predict a range of natural phenomena. The term ''law'' has diverse usage in many cases (approximate, accurate, broad, or narrow) ...
, but behave differently from normal materials. In essence these ''negative index metamaterials'' were noted for having the ability to reverse many of the physical properties that govern the behavior of ordinary optical materials. One of those unusual properties is the capability to reverse, for the first time, the Snell's law of refraction. Until this May 2000 demonstration by the UCSD team, the material was unavailable. Advances during the 1990s in fabrication and computation capabilities allowed these first
metamaterial A metamaterial (from the Greek word μετά ''meta'', meaning "beyond" or "after", and the Latin word ''materia'', meaning "matter" or "material") is any material engineered to have a property that is not found in naturally occurring materials. ...
s to be constructed. Thus, testing the "new" metamaterial began for the effects described by
Victor Veselago Victor Georgievich Veselago (13 June 1929, Ukraine – 15 September 2018)microwave frequency domain. Reversal of group velocity was explicitly announced in the related published paper. Summary of milestones in metamaterial research. There is also a list of peer reviewed articles pertaining to the research achievements of the Smith Group.


The super lens

The super lens or superlens is a practical structure based on
John Pendry Sir John Brian Pendry, (born 4 July 1943) is an English theoretical physicist known for his research into refractive indices and creation of the first practical " Invisibility Cloak". He is a professor of theoretical solid state physics at Impe ...
's work describing a perfect lens that can go beyond the
diffraction limit The resolution of an optical imaging system a microscope, telescope, or camera can be limited by factors such as imperfections in the lenses or misalignment. However, there is a principal limit to the resolution of any optical system, due to t ...
by focusing all four
fourier component A Fourier transform (FT) is a mathematical transform that decomposes functions into frequency components, which are represented by the output of the transform as a function of frequency. Most commonly functions of time or space are transformed, ...
s. Pendry's paper described a theoretical novel lens that could capture images below the diffraction limit by employing the
negative refractive index Negative-index metamaterial or negative-index material (NIM) is a metamaterial whose refractive index for an electromagnetic wave has a negative value over some frequency range. NIMs are constructed of periodic basic parts called unit cells, whi ...
behavior. The super lens is a practical realization of this theory. It is a working lens that can capture images below the diffraction limit even though limitations occur due to the inefficiencies of conventional materials. This means that although there are losses, enough of an image is returned to show this work was a successful demonstration.


Invisibility cloak

Ulf Leonhardt was born in
East Germany East Germany, officially the German Democratic Republic (GDR; german: Deutsche Demokratische Republik, , DDR, ), was a country that existed from its creation on 7 October 1949 until its dissolution on 3 October 1990. In these years the state ...
, and presently occupies the theoretical physics chair at the
University of St. Andrews (Aien aristeuein) , motto_lang = grc , mottoeng = Ever to ExcelorEver to be the Best , established = , type = Public research university Ancient university , endowment ...
in
Scotland Scotland (, ) is a Countries of the United Kingdom, country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a Anglo-Scottish border, border with England to the southeast ...
, and is considered one the leaders in the science of creating an invisibility cloak. Around 1999, Leonhardt began work on how to build a cloaking device with a few other colleagues. Leonhardt stated that at the time invisibility was not considered fashionable. He then wrote a theoretical study entitled "''Optical Conformal Mapping''". The first sentence sums up the objective: "An invisibility device should guide light around an object as if nothing were there." In 2005, he sent the paper to three notable
scientific journals In academic publishing, a scientific journal is a periodical publication intended to further the progress of science, usually by reporting new research. Content Articles in scientific journals are mostly written by active scientists such as s ...
,
Nature Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are ...
,
Nature Physics ''Nature Physics'' is a monthly peer-reviewed scientific journal published by Nature Portfolio. It was first published in October 2005 (volume 1, issue 1). The chief editor is Andrea Taroni, who is a full-time professional editor employed by this ...
, and
Science Science is a systematic endeavor that Scientific method, builds and organizes knowledge in the form of Testability, testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earli ...
. Each journal, in turn, rejected the paper. In 2006,
Physical Review Letters ''Physical Review Letters'' (''PRL''), established in 1958, is a peer-reviewed, scientific journal that is published 52 times per year by the American Physical Society. As also confirmed by various measurement standards, which include the ''Journa ...
rejected the paper for publication, as well. However, according to the PRL assessment, one of the anonymous reviewers noted that (he or she ) had been to two meetings in the previous months with
John Pendry Sir John Brian Pendry, (born 4 July 1943) is an English theoretical physicist known for his research into refractive indices and creation of the first practical " Invisibility Cloak". He is a professor of theoretical solid state physics at Impe ...
's group, who were also working on a cloaking device. From the meetings, the reviewer also became aware of a patent that Pendry and his colleagues were supposed to file. Leonhardt was at the time unaware of the Pendry group's work. Because of the Pendry meetings, Leonhardt's work was not really considered new physics by the reviewer and, therefore, did not merit publication in Physical Review Letters. Later in 2006, ''
Science Science is a systematic endeavor that Scientific method, builds and organizes knowledge in the form of Testability, testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earli ...
'' (the journal) reversed its decision and contacted Leonhardt to publish his paper because it had just received a theoretical study from Pendry's team entitled "''Controlling Electromagnetic Fields''". ''Science'' considered both papers strikingly similar and published them both in the same issue of
Science Express The Science Express is a mobile scientific exhibition for children mounted on a train which travels across India. The project was launched on 30 October 2007 at the Safdarjung railway station, Delhi by the Department of Science and Technology ...
on May 25, 2006. The published papers touched off research efforts by a dozen groups to build cloaking devices at locations around the globe, which would test out the mathematics of both papers. *Two theoretical studies appeared strikingly similar to the academic journal
Science Science is a systematic endeavor that Scientific method, builds and organizes knowledge in the form of Testability, testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earli ...
,
Only months after the submission of notable invisibility cloak theories, a practical device was built and demonstrated by David Schurig and David Smith, engineering researchers of Duke University (October 2006). It was limited to the
microwave Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ra ...
range so the object was not invisible to the human eye. However, it demonstrated
proof of principle Proof of concept (POC or PoC), also known as proof of principle, is a realization of a certain method or idea in order to demonstrate its feasibility, or a demonstration in principle with the aim of verifying that some concept or theory has prac ...
.


Transformation optics

The original theoretical papers on cloaking opened a new science discipline called
transformation optics Transformation optics is a branch of optics which applies metamaterials to produce spatial variations, derived from coordinate transformations, which can direct chosen bandwidths of electromagnetic radiation. This can allow for the constructi ...
.


See also

*
Metamaterial cloaking Metamaterial cloaking is the usage of metamaterials in an invisibility cloak. This is accomplished by manipulating the paths traversed by light through a novel optical material. Metamaterials direct and control the propagation and transmission o ...
*
Acoustic metamaterials An acoustic metamaterial, sonic crystal, or phononic crystal, is a material designed to control, direct, and manipulate sound waves or phonons in gases, liquids, and solids ( crystal lattices). Sound wave control is accomplished through manipulat ...
* Quantum metamaterials *
Photonic metamaterials A photonic metamaterial (PM), also known as an optical metamaterial, is a type of electromagnetic metamaterial, that interacts with light, covering terahertz ( THz), infrared (IR) or visible wavelengths. The materials employ a periodic, cellul ...
* Nonlinear metamaterials *
Seismic metamaterials A seismic metamaterial, is a metamaterial that is designed to counteract the adverse effects of seismic waves on artificial structures, which exist on or near the surface of the earth. Current designs of seismic metamaterials utilize configurations ...
*
Metamaterial absorber A metamaterial absorber is a type of metamaterial intended to efficiently absorb electromagnetic radiation such as light. Furthermore, metamaterials are an advance in materials science. Hence, those metamaterials that are designed to be absorbers ...
* Plasmonic metamaterials *
Terahertz metamaterials A terahertz metamaterial is a class of composite metamaterials designed to interact at terahertz (THz) frequencies. The terahertz frequency range used in materials research is usually defined as 0.1 to 10 THz.This corresponds to wavelengths bel ...
* Tunable metamaterials *
Split-ring resonator A split-ring resonator (SRR) is an artificially produced structure common to metamaterials. Its purpose is to produce the desired magnetic susceptibility (magnetic response) in various types of metamaterials up to 200 terahertz. These media cr ...
*
Theories of cloaking Theories of cloaking discusses various theories based on science and research, for producing an electromagnetic cloaking device. Theories presented employ transformation optics, event cloaking, dipolar scattering cancellation, tunneling light tra ...


Notes


References


Further reading and general references

* * * * * * * Description of building a mobile metal plate antenna. *Invited paper: * – Technical review of metamterials research. * * Slyusar V.I. Metamaterials on antenna solutions.// 7th International Conference on Antenna Theory and Techniques ICATT’09, Lviv, Ukraine, October 6–9, 2009. - pp. 19 – 2


External links

* {{History of physics Metamaterials
Metamaterials A metamaterial (from the Greek word μετά ''meta'', meaning "beyond" or "after", and the Latin word ''materia'', meaning "matter" or "material") is any material engineered to have a property that is not found in naturally occurring materials. ...
Antennas (radio)