Polarization by dichroic crystals

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Dichroism is exhibited by a number of minerals and by some organic compounds. The best known of the mineral crystals is tourmaline. When the ordinary light is sent through a thin slab of tourmaline crystal, the transmitted light is polarized. We take two crystals like T1, and T2  both are parallel each other. The light transmitted by a first crystal is also transmitted by the second crystal. But suppose we rotate second crystal through 900, no light transmitted. Because the absorption by tourmaline of all light rays vibrating in one particular plane not all plane.


Attempts to produce polarizing crystals of large aperture were made by Herapath in 1852. He was successful in producing small crystals of the organic compound quinine iodsulfate now it is known as herapathite. In 1932 Land was invented Polaroid and has found used in many different kinds of optical instruments.(Land was a scientist who invented polaroid) Land and Rogers found further that when an oriented transparent film of polyvinyl alcohol is heated in the presence of an active dehydrating catalyst such as hydrogen chloride, the film darkens slightly and becomes strongly dichroic.

Now a day polarizing films have more usage. Polarizing films are usually mounted between two thin plates of optical glass. These polarizing films are used as increasing wavelength of light rays in some other light transmitted systems. Like a car head light we add this polarized films that will help to increase wavelength of light rays.

Polarization by dichroic crystals Polarization by dichroic crystals Reviewed by knowledge people creators on May 12, 2019 Rating: 5
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