晶体拉曼放大器是获得高光束质量、高光谱纯度、高功率拉曼激光的重要途径。通过引入四个归一化综合参量, 推导出了外腔拉曼放大器的归一化输运方程组。通过数值求解该输运方程组得到了描述拉曼放大器运转的一组普适理论曲线; 分析了复合归一化变量对拉曼放大器性能的影响; 研究了晶体拉曼放大器放大率、放大后拉曼脉冲形状、光-光转换效率等参量在泵浦脉冲功率密度、泵浦脉冲与被放大脉冲相对宽度、泵浦脉冲与被放大脉冲时间重叠性等条件的变化规律。用实验数据对归一化理论进行了验证, 结果表明, 理论结果与实验数据相吻合, 证明了文中理论计算的正确性和可行性。

Crystalline Raman amplifier is an important way to obtain high beam quality, high spectral purity and high power Raman laser. The normalized transport equations of the external cavity Raman amplifier were derived by inducing four normalized composite parameters. A set of universal theoretical curves describing the operation of Raman amplifiers were obtained by numerical solving the transport equations, and the influence of the complex normalized variables on the performance of the Raman amplifiers was analyzed. The dependences of the magnification of the Raman pulse peak intensity, pulse shape of the output Raman laser, and the conversion efficiency from pumping laser to output Raman laser on the pumping pulse intensity, the relative width of the pumping pulse and Raman seed pulse, and the time overlap of the pumping pulse and Raman seed pulse were studied in detail. The optimum working condition of crystalline Raman amplifier was explored. The normalized theory was verified with actual experimental data. It is indicated that the theoretical results are consistent with the measured data. The normalized rate-equation model is proved to be precise and feasible.