Photoelastic Properties of Trigonal Crystals

Crystals

Anatoliy Andrushchak¹  Oleh Buryy²  Bohdan Mytsyk³  Nataliya Demyanyshyn³ 

[1] Department of Applied Physics and Nanomaterials Science, Lviv Polytechnic National University, Bandery str. 12, 79013 Lviv, Ukraine;Department of Semiconductor Electronics, Lviv Polytechnic National University, Bandery str. 12, 79013 Lviv, Ukraine;Optical Department, Karpenko Physico-Mechanical Institute of NAS of Ukraine, Naukova str. 5, 79060 Lviv, Ukraine;

关键词: piezo-optic effect;    elasto-optic effect;    interferometric method;    lithium tantalate;    lithium niobate;    catangasite;   

DOI  :  10.3390/cryst11091095

来源: DOAJ

【 摘 要 】

All possible experimental geometries of the piezo-optic effect in crystals of trigonal symmetry are studied in detail through the interferometric technique, and the corresponding expressions for the calculation of piezo-optic coefficients (POCs) π_im and some sums of π_im based on experimental data obtained from the samples of direct and X/45°-cuts are given. The reliability of the values of POCs is proven by the convergence of π_im obtained from different experimental geometries as well as by the convergence of some sums of POCs. Because both the signs and the absolute values of POCs π₁₄ and π₄₁ are defined by the choice of the right crystal-physics coordinate system, we here use the system whereby the condition S₁₄ > 0 is fulfilled (S₁₄ is an elastic compliance coefficient). The absolute value and the sign of S₁₄ are determined by piezo-optic interferometric method from two experimental geometries. The errors of POCs are calculated as mean square values of the errors of the half-wave stresses and the elastic term. All components of the matrix of elasto-optic coefficients p_in are calculated based on POCs and elastic stiffness coefficients. The technique is tested on LiTaO₃ crystal. The obtained results are compared with the corresponding data for trigonal LiNbO₃ and Ca₃TaGa₃Si₂O₁₄ crystals.

【 授权许可】

Unknown