中文摘要：

采用有限差分方法分析模拟了高功率端泵Nd：YAG复合棒的三维热应力分布,并与不含端帽的情况作了对比。研究了非对称泵浦、端帽厚度、冷却边界条件、激光介质尺寸和材料特性等参数对三维热应力分布的影响。计算结果表明：采用复合棒结构能够改善介质的热分布,减小介质表面的张应力（由无端帽时的136MPa减少到8.6MPa）,因此这种结构允许激光器获得大功率的激光输出。数值计算结果与Anasys软件模拟的结果一致,与已知实验结果定性相符。文中采用的有限差分方法避免了超大型矩阵运算,提高了计算精度和运算速度,对高功率固体激光器的优化设计有实际价值。

英文摘要：

Three dimensional （3D） thermal stress distribution of diode end-pumped composite Nd： YAG rod was analysed and simulated with finite difference method, compared with the case of noncomposite Nd：YAG rod. The effects of asymmetric pumping, thickness of the end-cap, boundary cooling condition, dimension and material characteristics of laser rod, etc, on the three dimensional thermal stress distribution were also studied. Calculated results indicate that composite rod structure can improve homogeneous of thermal distribution of the medium, reduce the tensile stress on the surfaces （from 136 MPa with out-end-cap to 8.6 MPa with end-cap）, and allow laser output the high power laser. The calculated results agreed with the analog results using Anasys software, with the known experiment results qualitatively. The calculation of super-large matrix could be avoided, and the calculation precision and calculation speed coule be improved using the finite difference method. It＇s practical value for designing high power lasers.