多程放大中激光脉冲交叠放大的物理建模与计算方法

Physical modeling and caculation method of laser pulse superposition in multi-pass amplification process

建立了多程放大中激光脉冲在增益介质中交叠放大的物理模型,并提出相应的计算方法.物理模型中考虑了脉冲前后沿对增益介质中反转粒子数的共同消耗.研究认为模型在延时系下的数据递推方式无法求解交叠放大问题.通过建立新的时空坐标系,解决了交叠放大过程的数值求解问题.基于此物理模型和计算方法,模拟计算了双程放大时脉冲时间波形与腔镜位置的关系.

Physical model and caculation method are established to describe the laser pulse superpositon in multi-pass amplification process. In this model, the inversion pupulation density is consumed by the pulse leading edge and tailing edge simultaneously. It is demonstrated that this model can not solve the problem of laser superposition amplification in the time-delay coordination. The superposition amplification is solved by building a new time-space coorination. Base on the physical model and caculation method, computer simulation is performed and the pulse shape distortion is discussed at different cavity mirror positions in two-pass amplification process.