稳定高质量光参量啁啾脉冲放大系统优化设计

要实现光参量啁啾脉冲放大(OPCPA)系统稳定、高质量输出,需要同时对光参量放大和泵浦光倍频这两个非线性过程进行优化设计。在光参量放大系统优化设计中,建立了描述光参量放大过程的多种简化物理模型;通过模拟泵浦光和信号光口径匹配关系,分析了放大信号光空间两维对称性并提出了优化方法;建立了非线性晶体最佳长度确定及调谐方法,以实现信号光输出高稳定性。在泵浦光倍频系统优化设计过程中,提出应用位相失配法实现稳定倍频输出,研究表明这种方法不仅能实现倍频光能量起伏抖动远远小于基频光能量的起伏抖动,而且能减小泵浦光近场调制度和时间波形调制,极大地改善输出倍频光光束质量,进而提高OPCPA系统输出信号光质量。

Optimization design of stable and high quality optical parametric chriped pulse amplification system

This paper proposes that in order to realize high-quality and stable output from an optical parametric chirped pulse amplification(OPCPA) system, the two nonlinear courses included in an OPCPA system must be optimized at the same time. These two nonlinear courses are the optical parametric amplifying (OPA) course and the second harmonic generation(SHG) course of the pump. In order to optimize the parametric amplifier, several kinds of physical models are set up and they will be used to solve different kinds of problems. The analyzing method is set up to get symmetrical output signal in x and y from an optical parametric amplifier. The method of making certain the length of the nonlinear crystal is also set up to get the most stable OPA output. In the study of the second harmonic generation course, mismatched SHG is put forward to get stable second harmonic pump. The study shows that mismatched SHG can not only improve the stability of the pump, but also decrease the modulation in near field and pulse waveform, thus improve the beam quality of the pump.