Temperature behavior of thermal expansion and birefringence of In x Tl 1– х І-substitution solid solutions

Results of studying the optical properties of In x Tl1–х I solid solutions in the concentration domain of 0.4 ≤ х ≤ 0.9 are presented. The dependence of relative linear expansion of In x Tl1–х I crystals (Т = 300–520 K) has been obtained. In x Tl1–х I crystals (Т = 300–520 K). Based on this, the temperature dependence of thermal-expansion coefficient α has been found. Dependence of birefringence Δn i on temperature and concentration of the TlI component in the solid solution has been studied.