Analytical model for the thermo-optic coefficients of lithium triborate.

An analytical model for the refractive indices and the thermo-optic coefficients of LBO is concisely developed by using the available experimental data in temperature-tuned noncritical phase-matched wavelength conversion to modify the previous model based on the best fit. The developed model is further validated by exploiting a tunable optically pumped semiconductor laser with intracavity stimulated Raman scattering to generate the fundamental and Stokes wave for performing intracavity nonlinear optics with LBO. Two LBO crystals with different cut angles in the XY plane are systematically employed to perform second harmonic generation and sum frequency generation. Experimental results clearly confirm that the present model is superior to the previous models in the analysis of phase matched temperatures. The developed analytical model is expected to be greatly useful for various nonlinear wavelength conversions with LBO.