Temperature-dependent optical anisotropy of L-arginine phosphate single crystal

Abstract

The optical anisotropy at different temperatures (birefringence, complete optical gyration tensor, and optical indicatrix rotation) for a monoclinic crystal of L-arginine phosphate has been determined by using the high-accuracy universal polarimeter (HAUP) method at a wavelength of 632.8 nm. The thermal variation coefficients of the birefringence along the (010), (101), (100), and (-201) planes were found to be -25.9×10^-6 K^-1, 11.1×10^-6 K^-1, 6.4×10^-6 K^-1, and -10.7×10^-6 K^-1, respectively. The tensor components in terms of rotatory power were found to be ϱ₁₁=-6.6°/mm, ϱ₂₂=19°/mm^-1, ϱ₃₃=49.7°/mm, and ϱ₁₃=-43.7°/mm at room temperature.