Temperature sensitivity of phase-matched second-harmonic generation in LiIO/sub 3/

Measurements were made of the temperature dependence (between 23 and 65 degrees C) of the phase-matching angle theta /sub pm/ for type I frequency doubling of 1064-nm laser light in lithium iodate (LiIO/sub 3/). The measured value of d theta /sub pm//dT is -14.7+or-1 mu rad/ degrees C, which corresponds to a thermal sensitivity beta /sub T/=0.24+or-0.02 cm/sup -1// degrees C for this process. Also calculated is a value of d theta /sub pm//dT using experimentally determined thermooptic data available in the literature. The calculated value of d theta /sub pm//dT is -31+or-18 mu rad/ degrees C using literature values of n and dn/dT for LiIO/sub 3/. The extreme sensitivity of the calculated value of d theta /sub pm//dT to small errors in the thermooptic coefficients may be the reason for this discrepancy.>