当前的强场物理实验研究依赖于拍瓦级钛宝石啁啾脉冲放大系统。光参量啁啾脉冲放大(OPCPA)方式理论上可支持更高的峰值功率。然而，传统OPCPA放大不可避免地伴生出信号光的时空畸变与相干噪声，前者影响最佳的脉冲压缩和光束聚焦，后者破坏皮秒尺度的脉冲信噪比。这两个未解决的关键问题制约了拍瓦级OPCPA强激光系统正常开展强场物理实验。本申请项目根据参量放大中的时空畸变与相干噪声产生机理，创新性地提出了基于准参量放大(QPA)抑制时空畸变和基于ω-x耦合环境滤除相干噪声的新思路。对比传统强激光放大的啁啾脉冲环境(ω-t耦合)，理论研究ω-x耦合对放大器相干噪声特性的影响；对比传统OPCPA，理论研究QPA对时空畸变的抑制作用；构建集成了QPA和ω-x耦合的新型参量放大系统，实验验证其对抑制时空畸变和滤除相干噪声的综合效果。本项申请将为下一步发展理想的强激光参量放大技术提供新视角和研究基础。

State-of-the-art strong-field physics experiments nowadays are mainly launched with petawatt-scale lasers produced from Ti:Sapphire chirped-pulse amplification system. Optical parametric chirped-pulse amplification (OPCPA) presents as a promising approach to overcome the petawatt barrier. Nevertheless, traditional OPCPA are inherently susceptible to spatiotemporal distortions of signal pulse as well as the introduction of coherent noise, which prevents to achieve the best spatiotemporal compression/focusing and degrades the pulse contrast, respectively. The issues of spatiotemporal distortions and coherent noise remain unsolved and do limit the use of PW-scale OPCPA lasers in strong-field physics experiments. In this project, we propose to supress the spatiotemporal distortions relying on quasi-parametric amplification (QPA) technology, and filtrate coherent noise relying on an amplification environment of “ω-x coupling”. We theoretically study the production and evolution of spatiotemporal coherent noise in the “ω-x coupling” pulse environment, in comparison with the case in traditional chirped-pulse environment (i.e. “ω-t coupling” ). Besides, the effect of QPA on the suppression of spatiotemporal distortion on signal pulse is investigated with a controlled comparison with the case in traditional OPCPA. Furthermore, a brand-new parametric amplification system that integrates the QPA technology and “ω-x coupling” pulse environment is built up, where the suppression of spatiotemporal distortions and filtering of coherent noise results are experimentally verified. This project will provide new perspectives and important bases for the future development of ideal parametric-amplification technology.