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A Nomarski prism is a modification of the
Wollaston prism A Wollaston prism is an optical device, invented by William Hyde Wollaston, that manipulates polarized light. It separates light into two separate linearly polarized outgoing beams with orthogonal polarization. The two beams will be polarized a ...
that is used in
differential interference contrast microscopy Differential interference contrast (DIC) microscopy, also known as Nomarski interference contrast (NIC) or Nomarski microscopy, is an optical microscopy technique used to enhance the contrast in unstained, transparent samples. DIC works on the p ...
. It is named after its inventor, Polish and naturalized-French physicist
Georges Nomarski Georges (Jerzy) Nomarski (January 6, 1919 – 1997) was a Polish physicist and optics theoretician. Creator of differential interference contrast (DIC) microscopy, the method is widely used to study live biological specimens and unstained tissues a ...
. Like the Wollaston prism, the Nomarski prism consists of two birefringent crystal wedges (e.g.
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 ...
or
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 ...
) cemented together at the hypotenuse (e.g. with Canada balsam). One of the wedges is identical to a conventional Wollaston wedge and has the optical axis oriented parallel to the surface of the prism. The second wedge of the prism is modified by cutting the crystal so that the
optical axis An optical axis is a line along which there is some degree of rotational symmetry in an optical system such as a camera lens, microscope or telescopic sight. The optical axis is an imaginary line that defines the path along which light propagat ...
is oriented obliquely with respect to the flat surface of the prism. The Nomarski modification causes the light rays to come to a focal point outside the body of the prism, and allows greater flexibility so that when setting up the
microscope A microscope () is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisibl ...
the prism can be actively focused.


See also

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Glan–Foucault prism A Glan–Foucault prism (also called a Glan–air prism) is a type of prism which is used as a polarizer. It is similar in construction to a Glan–Thompson prism, except that two right-angled calcite prisms are spaced with an air gap instead of ...
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Glan–Thompson prism A Glan–Thompson prism is a type of polarizing prism similar to the Nicol and Glan–Foucault prisms. Design A Glan–Thompson prism consists of two right-angled calcite prisms that are cemented together by their long faces. The optical axes ...
*
Nicol prism A Nicol prism is a type of polarizer, an optical device made from calcite crystal used to produce and analyse plane polarized light. It is made in such a way that it eliminates one of the rays by total internal reflection, i.e. the ordinary ray ...
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Prism (optics) An optical prism is a transparent optics, optical element with flat, polished surfaces that are designed to refraction, refract light. At least one surface must be angled — elements with two parallel surfaces are ''not'' prisms. The most fami ...
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Rochon prism A Rochon prism is a type of polariser. It is made from two prisms of a birefringent material such as calcite, which are cemented together. The Rochon prism was invented by and is named after Abbé Alexis Marie Rochon. It is in many ways similar ...
*
Sénarmont prism The Sénarmont prism is a type of polariser. It is made from two prisms of a birefringent material such as calcite, usually cemented together. The Sénarmont prism is named after Henri Hureau de Sénarmont Henri Hureau de Sénarmont (6 Septemb ...


References

*{{cite journal, last=Allen, first=RD, author2=David, GB , author3=Nomarski, G , title=The zeiss-Nomarski differential interference equipment for transmitted-light microscopy., journal=Zeitschrift für wissenschaftliche Mikroskopie und mikroskopische Technik, date=November 1969, volume=69, issue=4, pages=193–221, pmid=5361069, url=http://zeiss-campus.magnet.fsu.edu/referencelibrary/abstracts/dic05.html


External links


Nomarski Prism Action in Polarized LightWavefront Shear in Wollaston and Nomarski Prisms
Polarization (waves) Prisms (optics) Microscopy