The expressions of the principal thermal refractive index coefficients of 7.5 mol.% Nb:KTiOPO_(4) crystals

摘要

Based on the autocollimation method results of the principal refractive indices of 7.5 mol.% Nb:KTiOPO_(4) (Nb:KTP) an/stals for the wavelengths 539.75, 632.8, 1079.5, and 1341.4 nm at the temperature range from 319.25 to 416.15 K, simple expressions of the thermal refractive index coefficients as a function of wavelengths are presented. They agree well with the measured results and can be used to calculate the principal thermal refractive index coefficients at different wavelengths in 7.5 mol.% Nb:KTP crystals for nonlinear optical device designing.