分析了空间啁啾对宽带光谱超短脉冲激光系统的影响, 提出了利用波前传感器研究神光II 5 PW (SG-II-5 PW)装置空间啁啾的实验方法。实验中采集了宽光谱超短脉冲激光经过展宽器及多级空间滤波器后的波前特征, 测量了系统光路产生的横向空间啁啾和波前像差中心相对系统光轴的偏移量, 并通过实时调节色散调节器来消除激光装置的空间啁啾。对比分析了横向空间啁啾被消除前后的波前分布, 计算结果表明SG-II-5 PW装置激光光束的聚焦性能和远场能量集中度可得到显著提升。

The influence of spatial chirp on broadband ultrashort pulse laser system is analyzed. An experimental method for studying spatial chirp in SG-II-5 PW setup with wavefront sensor is proposed. In experiments, the wavefront feature of broadband ultrashort pulse laser is collected after the pulse passing through the stretcher and multi-stage spatial filters, and the lateral spatial chirp and the offset of the wavefront aberration centre relative to the optical axis of the system are measured. The dispersion regulator is adjusted in real-time to eliminate the spatial chirp in the laser system. The wavefront distributions before and after the spatial chirp elimination are compared, and the theoretical simulation shows that the focusing performance and the far field energy concentration of laser from SG-II-5 PW system are improved obviously.