Thermal distortions in high-power end-pumped Nd:YVO₄ crystals

Abstract

A high-resolution infrared thermal imager is employed to measure temperature and fit the thermal conductivity of Nd:YVO4 crystal. A theoretical model to analyze the thermal distortion of end-pumped Nd:YVO4 crystals is established. Both simulations and experiments reveal that with high-power pumping, the thermal effects of Nd:YVO4 crystal cause spherical aberration as well as astigmatism. It is identified that the major cause of astigmatism is the anisotropy of the Nd:YVO4 crystals’ thermal conductivity. The influence of astigmatism on the ellipticity of the output beam is investigated, and the significance of astigmatism compensation is demonstrated. The experimental results agree well with the simulation results.