Abstract

The criteria for selecting a nonlinear optical crystal for high average power applications are the crystal nonlinear optical coefficient, birefringence, optical damage threshold, thermal conductivity, and thermo-optic (dn/dT) and absorption coefficients at the pump and generated wavelengths. The thermo-optic and absorption coefficients are important because they limit the high average power performance of the crystal by inducing a refractive index gradient whose magnitude increases with input power. This refractive index gradient prevents perfect phase-matching and thus reduces the harmonic conversion efficiency. We report the thermo-optic and absorption coefficients of potassium titanyl phosphate (KTP), lithium niobate (LiNbO₃) and lithium iodate (LilO₃) at 532/514.5 nm, 660 nm, 1064 nm and 1320 nm.

© 1987 Optical Society of America