为了分析低温Yb:YAG放大器的放大特性，基于Yb离子抽运动力学及脉冲放大特性，对低温下Yb:YAG激光放大器的放大性能进行了理论研究，计算了不同晶体尺寸、不同掺杂浓度、不同温度以及不同抽运功率密度下的放大性能，建立了低温下热分析三维模型，对低温热管理效果进行了数值模拟。结果表明抽运功率密度、激光晶体尺寸、工作温度等参数对激光器效率均有显著影响，在100~300 K的温度范围内随着抽运功率的增大，最佳工作温度逐渐上升，不同尺寸的晶体在相同抽运功率密度下，最佳工作温度也不同。在低温强抽运条件下，较厚晶体的热管理效果优于较薄晶体。

In order to analyze the amplification propertied of cryogenic Yb:YAG amplifier, based on pumping dynamics and pulse amplification performance, the ampification properties of cryogenics Yb:YAG amplifier is researched in simulation. The amplification performance on different size and concentration of crystal and different temperature and pumping power density is calculated. 3D thermal analysis model is used to simulate the thermal management effect. The results demonstrate that the pump power density, the size of laser medium and the temperature all have distinct effect on the optical to optical efficiency. In the temperature range of 100 K to 300 K, the optimal working temperature increase with the pump power density. With the same pump power density, the medium with different size have different optimal working temperature. In the condition of low temperature and strong pump, the thicker crystal has a better thermal management effect than a thinner crystal.