A Dove prism is a type of reflective

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 ...

which is used to invert an

image An image is a visual representation of something. It can be two-dimensional, three-dimensional, or somehow otherwise feed into the visual system to convey information. An image can be an artifact, such as a photograph or other two-dimensiona ...

. Dove prisms are shaped from a truncated right-angle

. The Dove prism is named for its inventor,

Heinrich Wilhelm Dove Heinrich Wilhelm Dove (6 October 1803 – 4 April 1879) was a Prussian physicist and meteorologist. Early years Dove was born in Liegnitz in the Kingdom of Prussia. Dove studied history, philosophy, and the natural sciences at the University of B ...

. Although the shape of this prism is similar to the shape described by a

Dovetail joint A dovetail joint or simply dovetail is a joinery technique most commonly used in woodworking joinery (carpentry), including furniture, cabinets, log buildings, and traditional timber framing. Noted for its resistance to being pulled apart (ten ...

, the etymology of the two is unrelated. A beam of light travelling parallel to the longitudinal axis, entering one of the sloped faces of the prism undergoes

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 ...

from the inside of the longest (bottom) face and emerges from the opposite sloped face. Images passing through the prism are flipped (mirrored), and because only one reflection takes place, the image is also inverted but not laterally transposed.

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 phenomeno ...

at the entrance and exit surfaces results in substantial image

astigmatism Astigmatism is a type of refractive error due to rotational asymmetry in the eye's refractive power. This results in distorted or blurred vision at any distance. Other symptoms can include eyestrain, headaches, and trouble driving at nig ...

when used in convergent light. Thus the Dove prism is used almost exclusively for images appearing at infinity. If the flat

hypotenuse In geometry, a hypotenuse is the longest side of a right-angled triangle, the side opposite the right angle. The length of the hypotenuse can be found using the Pythagorean theorem, which states that the square of the length of the hypotenuse equa ...

surface of a Dove prism is cut into a roof shape, the result is an

Amici roof prism An Amici roof prism, named for its inventor, the Italian astronomer Giovanni Battista Amici, is a type of reflecting prism used to deviate a beam of light by 90° while simultaneously inverting the image. It is commonly used in the eyepieces of ...

Rotation

A reflection in one axis of a plane is always

equivalent Equivalence or Equivalent may refer to: Arts and entertainment *Album-equivalent unit, a measurement unit in the music industry * Equivalence class (music) *'' Equivalent VIII'', or ''The Bricks'', a minimalist sculpture by Carl Andre *''Equiva ...

to a reflection and rotation in two other axes (with the angle between the source and image being twice the angle between the source and reflection axis of the prism). Thus, Dove prisms can be used to create ''beam rotators'', which have applications in fields such as

interferometry Interferometry is a technique which uses the ''interference'' of superimposed waves to extract information. Interferometry typically uses electromagnetic waves and is an important investigative technique in the fields of astronomy, fiber opt ...

astronomy Astronomy () is a natural science that studies astronomical object, celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and chronology of the Universe, evolution. Objects of interest ...

, and

pattern recognition Pattern recognition is the automated recognition of patterns and regularities in data. It has applications in statistical data analysis, signal processing, image analysis, information retrieval, bioinformatics, data compression, computer graphi ...

. Lesso and Padgett (1999) and Moreno et al. (2003, 2004) found that there is a change in the state of polarization of a beam of light on passing through a rotated dove prism. Polarization rotation in the infrared has been known for much longer. (Johnston 1977) The polarization-transforming properties of dove prisms are of particular interest because they can influence the signal measurement of the scientific instrument.

References

* * * *{{cite journal , first = L. H. , last = Johnston , year = 1977, title = Broadband polarization rotator for the infrared , journal = Applied Optics , volume = 16 , issue = 4 , pages = 1082–4 , doi = 10.1364/AO.16.001082 , pmid = 20168639 , bibcode = 1977ApOpt..16.1082J Prisms (optics)

Rotation

See also

References