用于拍瓦级激光系统的三维光参量啁啾脉冲放大的数值模拟

Three Dimensional OPCPA Numerical Simulations for a Petawatt Class Laser System

建立了光参量啁啾脉冲传输放大(OPCPA)的物理模型,采用分步傅里叶算法编写了三维OPA+CPA数值模拟程序,利用该程序可以研究OPCPA系统中的能量放大、增益窄化、自相位调制、空间自聚焦以及脉冲的时间信噪比等问题,对OPCPA系统进行优化设计。利用该程序对神光II第九路拍瓦升级系统(SG-II-U-PW)进行了数值模拟研究,计算结果表明,第九路光路无需作太大改动即可满足拍瓦升级指标,并提出了第九路主放大链的两种运行方案。三维OPA+CPA模拟程序经过简单修改后也可以对飞秒(fs)OPCPA系统、以及未来峰值功率为exawatt级(1018W)的激光系统进行优化设计。

An optical parametric chirped pulse amplification （OPCPA） physical model is presented, and a splitstep Fourier technique is used to develop a three-dimensional OPA＋CPA numerical code （3D OPA＋CPA code）, which can be used to model the broadband amplification, gaining narrowing, self-phase modulation, spatial selffocusing and the temporal signal-to-noise ratio （SNR） of OPCPA laser facility, and to optimize the design of OPCPA system. The SG-II-U-PW laser facility is studied numerically using this 3D OPCPA code, and the calculated results show that the ninth beam line is suitable to be modified for meeting the design goal of the SGII-U PW project. The 3D OPA ＋ CPA code can be modified with ease to model and optimize the designs of femtosecond OPCPA system, and especially the future laser facility with exawatt （10^18 W） peak intensity.