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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 to the Wollaston prism, but one ray (the ordinary ray) passes through the prism undeviated. The Sénarmont prism is similar but transmits the s-polarized ray undeviated. In both the Rochon and the Sénarmont prisms the undeviated ray is ordinary on both sides of the interface. Rochon prisms are commercially available, but for many applications other polarisers are preferred. See also * Nomarski prism *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 ... * Glan–Thompson prism * Glan–Foucault prism * Sénarmont prism R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polarizer
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-defined polarization, that is polarized light. The common types of polarizers are linear polarizers and circular polarizers. Polarizers are used in many optical techniques and instruments, and polarizing filters find applications in photography and LCD technology. Polarizers can also be made for other types of electromagnetic waves besides visible light, such as radio waves, microwaves, and X-rays. Linear polarizers ''Linear polarizers'' can be divided into two general categories: absorptive polarizers, where the unwanted polarization states are absorbed by the device, and beam-splitting polarizers, where the unpolarized beam is split into two beams with opposite polarization states. Polarizers which maintain the same axes of polari ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prism (optics)
An optical prism is a transparent optical element with flat, polished surfaces that are designed to refract light. At least one surface must be angled — elements with two parallel surfaces are ''not'' prisms. The most familiar type of optical prism is the triangular prism, which has a triangular base and rectangular sides. Not all optical prisms are geometric prisms, and not all geometric prisms would count as an optical prism. Prisms can be made from any material that is transparent to the wavelengths for which they are designed. Typical materials include glass, acrylic and fluorite. A dispersive prism can be used to break white light up into its constituent spectral colors (the colors of the rainbow) as described in the following section. Other types of prisms noted below can be used to reflect light, or to split light into components with different polarizations. Types Dispersive ''Dispersive prisms'' are used to break up light into its constituent spectral col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 birefringence is often quantified as the maximum difference between refractive indices exhibited by the material. Crystals with non-cubic crystal structures are often birefringent, as are plastics under mechanical stress. Birefringence is responsible for the phenomenon of double refraction whereby a ray of light, when incident upon a birefringent material, is split by polarization into two rays taking slightly different paths. This effect was first described by Danish scientist Rasmus Bartholin in 1669, who observed it in calcite, a crystal having one of the strongest birefringences. In the 19th century Augustin-Jean Fresnel described the phenomenon in terms of polarization, understanding light as a wave with field components in transverse pola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scratch hardness comparison. Large calcite crystals are used in optical equipment, and limestone composed mostly of calcite has numerous uses. Other polymorphs of calcium carbonate are the minerals aragonite and vaterite. Aragonite will change to calcite over timescales of days or less at temperatures exceeding 300 °C, and vaterite is even less stable. Etymology Calcite is derived from the German ''Calcit'', a term from the 19th century that came from the Latin word for lime, ''calx'' (genitive calcis) with the suffix "-ite" used to name minerals. It is thus etymologically related to chalk. When applied by archaeologists and stone trade professionals, the term alabaster is used not just as in geology and mineralogy, where it is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alexis-Marie De Rochon
Alexis-Marie de Rochon, known as Abbé Rochon, was born in Brest, France on 21 February 1741, and died in Paris on 5 April 1817. He was a French astronomer, physicist and traveller. He worked on lens design and crystal optics, inventing the Rochon prism polariser. Biography In 1769, Rochon was part of an expedition under Ensign Grenier to find new, quicker maritime routes between Isle de France and India. On 30 May 1769, the expedition departed, with the corvettes ''Heure du Berger'', under Grenier, and ''Vert-Galant'', under Commander La Fontaine. They were bound for Saint-Brandon, where they arrived on 2 June. They then sailed on the 5th Nazareth bank, then on Saya de Malha bank on 5 June, and continued North before sailing West to reach Seychelles, arriving at Mahé on 14 June. they then sailed to Praslin, spending the night of 14 there, and departed on 15. They sailed through the Maldives and arrived at Malabar coast on 29 July, and eventually at Pondichéry on 6 Augu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 according to the optical axis of the two right angle prisms. The Wollaston prism consists of two orthogonal prisms of birefringent material—typically a uniaxial material such as calcite Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on the Mohs scale of mineral hardness, based on scra .... These prisms are cemented together on their base (traditionally with Canada balsam) to form two right triangle prisms with perpendicular optic axes. Outgoing light beams diverge from the prism as ordinary and extraordinary rays due to the differences in the indexes of refraction, with the angle of diverg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 September 1808 – 30 June 1862) was a French mineralogist and physicist. He was born in Broué, Eure-et-Loir. From 1822 to 1826, he studied at the École Polytechnique in Paris, then furthered his education at the � .... It is similar to the Rochon and Wollaston prisms. In the Sénarmont prism the s-polarized ray (i.e., the ray with polarization direction perpendicular to the plane in which all rays are contained, called the plane of incidence) passes through without being deflected, while the p-polarized ray (with polarization direction in the plane of incidence) is deflected (refracted) at the internal interface into a different direction. Both rays correspond to ordinary rays (o-rays) in the first component prism, since both polarizatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nomarski Prism
A Nomarski prism is a modification of the Wollaston prism that is used in differential interference contrast microscopy. It is named after its inventor, Polish and naturalized-French physicist Georges Nomarski. Like the Wollaston prism, the Nomarski prism consists of two birefringent crystal wedges (e.g. quartz or calcite) 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 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 the prism can be actively focused. See also *Glan–Foucault prism *Glan–Thompson prism *Nicol prism *Prism (optics) *Rochon prism *S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 is eliminated and only the extraordinary ray is transmitted through the prism. It was the first type of polarizing prism, invented in 1828 by William Nicol (1770–1851) of Edinburgh. It consists of a rhombohedral crystal of Iceland spar (a variety of calcite) that has been cut at an angle of 68° with respect to the crystal axis, cut again diagonally, and then rejoined as shown, using a layer of transparent Canada balsam as a glue. Unpolarized light ray enters through the left face of the crystal, as shown in the diagram, and is split into two orthogonally polarized, differently directed rays by the birefringence property of calcite. The ''ordinary'' ray, or ''o''-ray, experiences a refractive index of ''n''o = 1.658 in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 of the calcite crystals are parallel and aligned perpendicular to the plane of reflection. Birefringence splits light entering the prism into two rays, experiencing different refractive indices; the ''p''-polarized ordinary ray is totally internally reflected from the calcite–cement interface, leaving the ''s''-polarized extraordinary ray to be transmitted. The prism can therefore be used as a polarizing beam splitter A beam splitter or ''beamsplitter'' is an optical device that splits a beam of light into a transmitted and a reflected beam. It is a crucial part of many optical experimental and measurement systems, such as interferometers, also finding wid .... Traditionally Canada balsam was used as the cement in assemb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 being cemented together. Total internal reflection of ''p''- polarized light at the air gap means that only ''s''-polarized light is transmitted straight through the prism. Design Compared to the Glan–Thompson prism, the Glan–Foucault has a narrower acceptance angle over which it works, but because it uses an air gap rather than cement, much higher irradiances can be used without damage. The prism can thus be used with laser beams. The prism is also shorter (for a given usable aperture) than the Glan–Thompson design, and the deflection angle of the rejected beam can be made close to 90°, which is sometimes useful. Glan–Foucault prisms are not typically used as polarizing beamsplitters because while the transmitted beam is complete ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
