环形激光二极管抽运激光棒的热致退偏分析

Analyses of Thermal Depolarization in Ring Laser Diode Array Side-Pumped Rod Laser

利用自行编制的热效应模拟软件 ,采用光线追迹方法获得激光棒内的热沉积分布 ,在此基础上利用热传导模型和热力光学模型 ,对高功率环形激光二极管阵列抽运的棒状激光放大器中动态热致退偏进行了详细模拟计算 ,并比较了不同输入功率下的热致退偏情况。结果表明 ,采用基于光线追迹的发热模型 ,可以很好地计算环形激光二极管抽运激光棒中的热效应问题 ;瞬态下的光程差分布和同消色线退偏图案的环数与棒内瞬态温升分布有关 ;输入功率越高 ,热效应引起的相对光程差就越大 ,波前畸变就越大 ,引起的热致退偏也就越严重 ,在同消色线图案中的环数就越多。

The thermal depolarization in ring laser diode array side-pumped rod laser is studied. Based on the intensity distribution of laser diode (LD), a inhomogeneous heat distribution in the laser rod has been obtained by using the ray tracing method. And then, the transient temperature rise and thermal stress distribution are obtained by using the finite element method. In this paper, the relative thermal optic pass difference (OPD) and output beam patterns with depolarization are simulated at both thermal steady state and transient state. Simulation results show that the thermal induced depolarization grows with the input power, and the transient depolarization grows with the temperature rise and reaches to a steady state as well.