Light index of refraction

In ellipsometry monochromatic light such as from a He-Ne laser, is passed through a polarizer, rotated by passing through a compensator before it impinges on the interface to be studied [142]. The reflected beam will be elliptically polarized and is measured by a polarization analyzer. In null ellipsometry, the polarizer, compensator, and analyzer are rotated to produce maximum extinction. The phase shift between the parallel and perpendicular components A and the ratio of the amplitudes of these components, tan are related to the polarizer and analyzer angles p and a, respectively. The changes in A and when a film is present can be related in an implicit form to the complex index of refraction and thickness of the film. 

Fig. 11. Index of refraction vs dispersion and optical classification of glasses. The shaded area indicates the region of glass formation. BaF = barium flint BaK = barium crown BaLF = light barium flint BaSF = heavy barium flint BK = borosilicate crown F = flint FK = fluorcrown K = crown ...

Materials. For holographic information storage, materials are required which alter their index of refraction locally by spotwise illumination with light. Suitable are photorefractive inorganic crystals, eg, LiNbO, BaTiO, LiTaO, and Bq2 i02Q. Also suitable are photorefractive ferroelectric polymers like poly(vinyhdene fluoride-i o-trifluorethylene) (PVDF/TFE). Preferably transparent polymers are used which contain approximately 10% of monomeric material (so-called photopolymers, photothermoplasts). These polymers additionally contain different initiators, photoinitiators, and photosensitizers. 

When exposed to light, the monomeric material in the photopolymers or photothermoplasts polymerizes, thus locally increasing density and index of refraction. A subsequent fixation process polymerizes the monomer throughout the polymer matrix. 

Fig. 17. Polymer dispersed Hquid crystal display (PDLC). (a) U < clear state, where U) is the threshold voltage of the ceU. and rij represent the indexes of refraction for light polarized parallel and perpendicular to the director of the Hquid crystal represents the index of refraction of the isotropic...

Considering Figure 1, radiation incident on a surface (light, X rays, or neutrons) will be reflected and refracted at the interface between the two media provided there is a difference in the index of refraction. In the case of neutrons and X rays, the refractive index of a specimen is slightly less than unity and, to within a good approximation, is given by... 

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