Birefringence, isotropic points, and optical filters based on CuGaxAl1-xSe(S)2 crystals

Abstract

A brief review on birefringence and optical filters based on CuGaxAl1-xS2 and CuGaxAl1-xSe2 crystals is given in this paper. Two types of isotropic points are analyzed; one of them refers to a case when the wavelength at which the ordinary and extraordinary refractive indices are equal is situated near the absorption edge, while in the second case the isotropic wavelength is in the region of crystal transparency. It is shown that both of them can be used for the development of band-pass and band-reject filters. The possibility of adjusting the spectral position of an isotropic point by changing the chemical composition of a solid solution is illustrated, and the applicability of CuGaxAl1-xS2 and CuGaxAl1-xSe2 for adjusting the isotropic point to most of Ar+, Kr+, He–Ne, and He–Cd gas lasers lines, as well as to semiconductor lasers, is revealed