高功率钕玻璃激光三倍频脉冲时间波形的研究

基于目前国内规模最大的激光驱动器——“神光Ⅱ”八路基频光已经实现功率平衡运行，通过改变其中若干路三倍频系统各调谐量的偏离，对输出三倍频波形进行束与束之间的横向对比研究．研究发现，对于Ⅱ类-Ⅱ类偏振失配三倍频系统，在影响转换效率的三个调谐量中，偏振分配角失配△θp，对三倍频波形影响最大；在入射基频功率密度约为1．0GW／cm^2情况下，当三倍频系统三个调谐量都处在最佳匹配时，三倍频波形半峰全宽τ最小。研究工作为最终实现“神光Ⅱ”八路光束三倍频功率平衡输出提供了晶体调试的方法。

On the laser driver "Shenguang II", eight fundamental beams have realized power balance. By changing detuning values of parameters of the frequency tripling systems, the output pulse shapes of the output beams are mutually compared. The experiment results indicate that for the type II-type II polarization- mismatch frequency tripling system, when the input intensity is abut 1 GW/cm(2), of the three parameters that influence the freguency tripling efficiency, polarization detuning angle Delta theta(p) has the most important effect on the pulse shape. When all three parameters of tripling system are at the optimized values, the full width at half maximum of pulse shape tau reaches minimum. This work describes the method of crystal adjustment to actualize the power balance of the eight frequency tripling beams.