环形激光二极管抽运棒状激光器中瞬态温度和热应力分析

Analyses of Transient Temperature and Thermal Stress Distribution in Ring Laser Diode Array Pumped Laser Rod

直接从激光二极管发光强度的角分布出发 ,采用光线追迹方法获得激光棒内的热沉积分布 ,在此基础上采用热传导模型和热力模型 ,比较了不同抽运功率、不同棒半径下达到稳态温度分布的时间 ,并且对稳态和瞬态热应力进行了详细模拟计算。结果表明 ,采用环形激光二极管阵列侧面抽运的棒状激光器中的热效应问题十分严重 ,不同的抽运结构参量下 ,温度分布不同 ;达到稳态所需时间随棒半径增大而增加 ,而不受抽运功率的影响 ;抽运功率越大 ,棒内温差增大 ,热应力也越大 ;热破坏主要集中于激光棒中心区域和表面区域。

Based on the intensity distribution of the pumping laser diode, the distribution of the heat deposition inside the gain medium of a ring laser diode array (LDA) side-pumped solid-state rod laser is obtained using the ray tracing method. The transient temperature rise and thermal stress distributions are calculated using the finite element method. Also, the temperature rise and thermal stress are discussed under different input power and different rod radius. The results show that temperature distributions are different under different pump structure parameters. And the rise time to steady state grows with increase of the rod radius but not with the pump power. The temperature rises with the pump power and so does the thermal stress, which may cause serious problems such as fracture around the center and surface of the laser rod.