Analyses of Birefringence Compensation for a Laser System with Two Tandem-set Nd:YAG Rods and Two Coupling Lenses
Y. Wang, T. Ogawa, S. Wada and H. Kan
We have performed an improved approach to analyze the structure of a tandem- set rod system with two coupling lenses and a 90º quartz rotator. The thermally induced lens effect has been taken into account in the evaluation. It can be seen that the reduction of depolarization caused by thermally induced birefringence in the laser rods has been intrinsically realized after the experimental examination. We also found that the birefringence characterization of such a side-pumped laser system for a one-way travelling wave is very different from that for a stationary wave. When designing the real laser resonator with a satisfied transversal mode, the mode-volume and birefringent compensation should be carefully investigated and balanced at the same time. The conclusion of this paper might be useful for construction of a real high-average-power laser oscillator with good beam quality.
Keywords: Thermally-induced birefringence, thermally-induced lens effect, transfer matrix, depolarization, one-way travelling wave, stationary wave, effective radius, Nd:YAG rods