Temperature sensitivity of phase-matched second-harmonic generation in LiIO3

Measurements were made of the temperature dependence (between 23 and 65°C) of the phase-matching angle θ_pm for type I frequency doubling of 1064-nm laser light in lithium iodate (LiIO₃). The measured value of dθ_pm/dT is -14.7±1 μrad/°C, which corresponds to a thermal sensitivity β_T =0.24±0.02 cm^-1/°C for this process. Also calculated is a value of dθ_pm/dT using experimentally determined thermooptic data available in the literature. The calculated value of dθ_pm/dT is -31±18 μrad/°C using literature values of n and dn/dT for LiIO₃. The extreme sensitivity of the calculated value of dθ_pm/dT to small errors in the thermooptic coefficients may be the reason for this discrepancy