Zhao Yang, Wu Fenxiang, Wang Cheng, Hu Jiabing, Zhang Zongxin, Liu Xingyan, Yang Xiaojun, Bai Peile, Chen Haidong, Qian Jiayi, Gui Jiayan, Xu Yi, Leng Yuxin, Li Ruxin
School of Physics Science and Engineering, Tongji University, Shanghai, 200092, China.
State Key Laboratory of High Field Laser Physics and CAS Center for Excellence in Ultra-Intense Laser Science, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai, 201800, China.
Sci Rep. 2024 Aug 6;14(1):18231. doi: 10.1038/s41598-024-68833-6.
The groove density mismatching of compression gratings, an often-neglected key issue, can induce significant spatiotemporal aberrations especially for super-intense femtosecond lasers. We mainly investigate the angular chirp and the consequent degradation of the effective focused intensity introduced by the groove density mismatching of compression gratings in ultra-intense femtosecond lasers. The results indicate that the tolerances of grating groove density mismatching will rapidly decrease with the beam aperture or spectral bandwidth increases. For our 100PW laser under construction, the grating groove density mismatching should be as small as 0.001 gr/mm if the drop of effective focused intensity has to be controlled below 15%. More importantly, new angular chirp compensation schemes are proposed for both double-grating and four-grating compressors. This work reveals the importance of groove density matching of compression gratings, and can provide helpful guidelines for the design of ultra-intense femtosecond lasers.
压缩光栅的刻槽密度失配是一个常被忽视的关键问题，它会引发显著的时空像差，尤其是对于超强飞秒激光而言。我们主要研究了超强飞秒激光中压缩光栅刻槽密度失配所引入的角啁啾以及随之而来的有效聚焦强度的降低。结果表明，随着光束孔径或光谱带宽的增加，光栅刻槽密度失配的容差将迅速减小。对于我们正在建造的100PW激光器，如果要将有效聚焦强度的下降控制在15%以下，光栅刻槽密度失配应小至0.001 gr/mm。更重要的是，针对双光栅和四光栅压缩器提出了新的角啁啾补偿方案。这项工作揭示了压缩光栅刻槽密度匹配的重要性，并可为超强飞秒激光器的设计提供有益的指导。
