The principal refractive indices and the thermal refractive-index coefficients of 7.5-mol.% Nb:KTiOPO<sub>4</sub> crystal were measured by autocollimation for wavelengths of 0.53975, 0.6328, 1.0795, and 1.3414 μm from room temperature to 143 °C. The Sellmeier equations at room temperature were obtained and used to calculate the optimal phase-matched angles for 1.0642 and 1.0795 μm. The calculated and experimental values are in good agreement.
© 1999 Optical Society of America
Hongyuan Shen, Deyin Zhang, Wen Liu, Wenzhi Chen, Guofang Zhang, Ge Zhang, and Wenxiong Lin, "Measurement of Refractive Indices and Thermal Refractive-Index Coefficients of 7.5-mol.% Nb:KTiOPO4 Crystal," Appl. Opt. 38, 987-990 (1999)