重频应用下等离子体电光开关热退偏损耗分析

 基于有限元数值方法，给出电光晶体KDP在高平均功率激光负载下温度场分布和应力场分布。在此基础上得到了折射率随温度变化、电光系数随温度变化、及应力双折射引入的退偏损耗。数值模拟显示：电光系数随温度变化和应力双折射是引起开关退偏损耗的主要因素。当入射激光平均功率为40 W、辐照时间为420 s时，KDP晶体最高温度为38.43 ℃,电光系数随温度变化及应力双折射引入的最大退偏损耗分别为2.38%和4.04%。实验测量了应力双折射导致的退偏损耗，实验结果和理论结果符合较好。

Depolarization loss analysis of electro-optic crystal KDP heated by repetition frequency laser

Temperature and thermal stress distributions in the KDP, heated by repetition frequency laser, are given by means of finite element methods. Depolarized loss, which is induced by temperature dependence of the refractive index, electro-optic coefficient, and by thermal-stress, is calculated. The simulated results indicate: variation of electro-optic coefficient as well as stress birefringence is the main factor, which induces depolarized loss of the switch. When the average power of the incident laser is 40 W, after 420 s irradiation, the highest temperature in KDP crystal is 38.43 ℃. The largest depolarized loss induced by variation of electro-optic coefficient and stress birefringence is correspondingly 2.38%, 4.04%. Depolarized loss, induced by stress birefringence, is measured. The mea