热边界和泵浦结构对激光晶体热效应的影响

Influence of boundary condition and pump scheme on thermal effects of laser crystal

报道了不同热边界和泵浦结构下激光晶体的热效应情况。理论上,基于星载激光器的工作特点,通过建立符合激光晶体工作状态的热模型,模拟了Nd:YAG晶体受到具有高斯分布半导体激光侧面泵浦时的温度场分布,分析了热边界、泵浦方式以及泵浦光斑、吸收系数等泵浦参数对温度场的影响。将激光晶体热透镜作薄透镜近似,进行了热透镜焦距理论计算和实验测量。五面环形泵浦结构,泵浦功率4 500 W,10 Hz重复频率下,Nd:YAG晶体的热透镜焦距约9.5 m,实验结果与理论仿真结果基本符合。文中建立的模型与实验方法为预测激光晶体的热效应提供了一种有效工具,为激光器设计提供依据。

The crystal＇s thermal effects under different thermal boundary and pump structure were reported. In theory, based on operating characters of space laser, a thermal model satisfying crystal working state was set up. The temperature distribution of Nd：YAG crystal was simulated for diode laser with Gaussian beam distribution side pumped laser, and the influence of thermal boundary condition, pump manner and pump parameters on thermal distribution was analyzed. With assumption that the thermal lens of crystal was thin lens, the thermal focal length was calculated theoretically and measured experimentally. With five-side annular pump structure, pump power of 4 500 W and pump repetition frequency of 10 Hz, the thermal focal length of Nd：YAG was about 9.5 m. Experimental results are in basic agreement with the simulated results.