抄録
The present status of the measurement of thermal birefringence and its compensation in laser-diode (LD) pumped Nd:glass laser rods is reviewed. To measure the two-dimensional (2D) thermal birefringence in solid-state laser materials such as Nd:glass (HAP4) a high-sensitivity polarimeter is introduced.This polarimeter can sensitively measure the direction of the principal birefringence axis as well as the phase shift δ with sign when δ < π/4. The 2D thermal birefringence and its compensation in a LD pumped Nd:glass (HAP4) rods are successfully measured with this polarimeter. The birefringence compensation is reported by inserting a 90° rotator between two identical LD pumped Nd:glass rods with conduction cooling. The birefringence loss due to this thermal birefringence in a polarized laser cavity can be estimated by using Jones matrix. A considerable reduction of birefringence loss from 9.8% to less than 0.9% after compensation is performed.
