以激光二极管（LD）端面泵浦方形YAG/Yb∶YAG复合晶体为研究对象，采用有限元分析方法，并根据热传导理论以及连续LD端面泵浦方形YAG/Yb∶YAG的工作特点，系统分析了泵浦功率、YAG晶体厚度及截面尺寸对激光晶体温度、热应力及热形变的影响。计算过程中经光学耦合系统准直聚焦的泵浦光斑半径为400 μm。研究结果表明：当Yb∶YAG晶体尺寸为4 mm×4 mm×1 mm，YAG晶体厚度为0.1 mm时，随着泵浦功率由60 W增加为80 W，YAG/Yb∶YAG方片晶体内最高温升明显增大，由37.19 ℃变为82.92 ℃；当YAG晶体厚度由0 mm增加为0.5 mm时，薄片晶体内最大热应力由26.93 MPa变为10.438 MPa，最高温升也随之降低了18.18 ℃，但由热应力产生的热形变基本保持不变。利用方片YAG/Yb∶YAG复合晶体能够有效降低激光晶体内最大热应力及最高温升，对全固态Yb∶YAG激光器的设计及高功率输出具有指导意义。

Laser diode (LD) end-pumped square YAG/Yb∶YAG composite crystal is taken as the study specimen. Based on the theory of heat conduction and working characteristics of continuous LD end-pumped square YAG/Yb∶YAG, the effects of pump power, thickness, and section size of YAG crystal on temperature, thermal stress, and thermal deformation of laser crystal is systematically investigated using finite element method. The pump spot radius of collimation focused using an optical coupling system is 400 μm in the calculation process. The findings show that when the size of Yb∶YAG crystal is 4 mm×4 mm×1 mm, and the thickness of YAG crystal is 0.1 mm, the maximum temperature rise in YAG/Yb∶YAG square crystal increases from 37.19 ℃ to 82.92 ℃ with the increase in pump power from 60 W to 80 W. When the YAG crystal's thickness increases from 0 mm to 0.5 mm, the maximum thermal stress changes from 26.93 MPa to 10.438 MPa, and the maximum temperature decreases by 18.18 ℃, but the thermal deformation due to thermal stress remains unchanged. The use of square YAG/Yb∶YAG composite crystal can efficiently decrease the maximum thermal stress and temperature rise in laser crystal, which has guiding significance for the design and high power output of all-solid Yb∶YAG laser.