Thermal Birefringence Effect on Performance of LD Pumped Nd: glass Laser

Abstract

We have developed a highly sensitive two-dimensional (2D) polarimeter. This polarimeter was successfully used to measure the 2D birefringence distribution in thermally-induced-birefringence-compensated LD pumped Nd: glass (HAP4) laser under lasing (1054nm) and nonlasing condition. The energy loss due to birefringence was estimated quantitatively using Jones matrix. The thermal birefringence was reduced under the lasing condition compared to the non lasing condition. By inserting a 90 degree quartz rotator between two identically LD pumped Nd: glass rods, almost perfect birefringence compensation was achieved with very little residual birefringence. A considerable reduction of birefringence loss from over 12% before compensation to less than 0.4% after compensation was observed. The output performence of this laser was in a good agreement with the estimation after taking into account of the birefringence loss.