高重频脉冲串激光再生放大技术及其抖动抑制方法研究

High-speed planar laser-induced fluorescence (PLIF) technique has many important applications such as supersonic injection and large-scale gas turbine. A high-repetition-rate, high-pulse-energy laser source is essential to achieve a high temporal and spatial resolution in these applications. In recent years, plenty of attention has been paid to obtain high-performance laser source for PLIF technique. In this project, a new-type regenerative amplifier with gain modulation is utilized to solve the ubiquitous problem about low extraction efficiency in pulse burst systems. Regenerative amplifier is beneficial for low energy laser to get high gain as well as a high extraction efficiency. Study on the dynamics of bifurcation generation in regenerative amplifier is conducted, and a method with gain modulation is employed to improve the stability in regenerative amplifier. A slab-type laser medium is used to get high absorption efficiency. Finally, on the basis of study on the theory of laser amplification and the numerical simulation, high efficient laser amplification for high-repetition-rate pulse burst laser with low bifurcation is realized.

高速平面激光诱导荧光技术（planar laser-induced fluorescence，PLIF）在超高声速飞行器和大型燃气轮机等研究领域具有重要的应用前景。高重复频率、大能量的脉冲串激光器是PLIF诊断仪的关键组成部分。本课题针对现有系统提取效率低、造价高的问题，理论研究高重复频率再生激光放大器，分析能量提取效率随关键参量的变化规律，对高重复频率再生激光放大器进行优化设计；研究谐振腔内增益变化机理，分析再生放大器脉冲抖动产生机制，采用附加谐振腔实现对再生放大器中的增益调制，解决高重复频率再生放大器中脉冲不稳定的问题。在激光放大理论分析和数值模拟的基础上，优化设计方案，最终实现高重复频率脉冲串激光的高效率、高稳定性的再生放大。

高速平面激光诱导荧光技术在高超声速飞行器和大型燃气轮机等研究领域具有重要的应用前景。高重复频率、大能量脉冲串激光器是决定诊断仪工作重复频率和信噪比的关键组成部分。本课题通过建立高重复频率脉冲串激光放大器理论模型，理论分析脉冲串激光抖动的主要原因，实验研究脉冲串激光放大器输出性能，实现了高效率、高稳定性的高重复频率脉冲串激光放大，100kHz脉冲串激光单脉冲能量达到9.5mJ，能量抖动由13.5%降低为7.5%，提取效率25%。共发表学术论文11篇，申请发明专利1项，培养研究生4人，受邀参加国际学术会议4次。