将倍频过程视为一种随基波光子数变化而变化的非线性腔内损耗, 对被动调Q四能级速率方程进行修正, 总结出了被动调Q绿光激光器的四能级非线性速率方程。通过数值求解, 对连续LD泵浦Nd∶GdVO4/Cr4+∶YAG/KTP和Nd∶YAG/ Cr4+∶YAG/LBO腔内倍频被动调Q绿光激光器的输出特性进行了数值模拟。通过与实验数据进行比较, 理论结果与实验数据相吻合, 证明此速率方程对腔内倍频被动调Q绿光激光器普遍适用, 所得结果对该类器件参数设计和优化具有指导意义和参考价值。

Regarding frequency doubling process as an intracavity loss which changes with the transformation of the fundamental photon number, the four-level nonlinear rate equation of passively Q-switched laser is modified, and the four-level nonlinear rate equation of passively Q-switched green laser is summarized. The output characteristics of the LD pumped Nd∶GdVO4/Cr4+∶YAG/KTP and Nd∶YAG/ Cr4+∶YAG/LBO intracavity frequency doubling passively Q-switched green laser are simulated through numerical solution. After the comparison with the experimental data, the theoretical analysis accords with the experimental results, it proves that the rate equation is universally applicable to the intracavity frequency doubling passively Q-switched green laser. The results obtained have guiding significance and reference value to the parameter design and optimization of these devices.