利用主动调Q的自拉曼激光器,抑制主要频移拉曼模,使次级拉曼模受激拉曼散射输出新波长的拉曼光。首先,进行理论推导得到包含两个拉曼项的主动调Q归一化速率方程,由典型的实验装置参数和常用晶体参数对归一化拉曼增益系数、归一化损耗比、归一化初始反转粒子数进行取值。其次,通过数值模拟研究归一化参量对两束拉曼光脉冲的影响,找到可以实现次级拉曼模受激拉曼散射的参量取值范围。最后,利用实验参数计算得到的归一化变量值进行数值模拟,对结果进行分析并给出优化方案。

Using actively Q-switched self-Raman lasers to suppress the main frequency-shifted Raman mode, so that the Raman mode with relatively lower gain coefficient is stimulated Raman scattering to output Raman light with a new wavelength. First, the theoretical derivation of the actively Q-switched normalized rate equations with two Raman modes are deduced, and the normalized Raman gain coefficient, normalized loss ratio, and normalized initial population inversion density are evaluated by the basic parameters of typical experiment and common crystals. Secondly, the influence of normalized variables on the output characteristics of two Raman light pulses are studied through numerical simulation, and the range of parameters that can realize the stimulated Raman scattering of the Raman mode with relatively lower gain coefficient is found. Finally, the normalized variable values derived from the experimental parameters are numerically simulated. The results are analyzed and the optimization scheme is given.