通过对四能级系统速率方程的分析 ,采用 M2因子来描述泵浦光在激活介质中的传播规律 ,给出了含有泵浦光光束质量因子 M2 和激活介质特征参数在内的泵浦阈值、输出功率和斜转换效率的解析表达式。在激活介质中泵浦光有效泵浦体积最小的条件下 ,对输出功率进行了最佳化 ,从而确定激光腔的最优参数选择。据上述理论 ,对 L D纵向泵浦、自聚焦透镜耦合的 Nd:YVO4激光器进行了研究 ,实验结果与理论相符。 Based on the analysis of the four-level system velocity equation, the M2 factor is used to describe the propagation law of pump light in the activation medium, and the pump threshold including the pump beam quality factor M2 and the activation medium characteristic parameters is given. Output power and oblique conversion efficiency of the analytical expression. The output power is optimized under the condition of the pump effective pumping volume is minimized in the activation medium, so as to determine the optimal parameter selection of the laser cavity. According to the above theory, the Nd: YVO4 laser with L D longitudinal pump and self-focusing lens is studied. The experimental results are consistent with the theory.