Viability verification of asymmetric four-grating compressor in SEL-100 PW frontend

The laser-induced damage observed in optics has rendered compressor grating the most limited component in petawatt (PW) lasers, owing to the considerable challenges associated with manufacturing gratings possessing both a sufficiently high damage threshold and large dimensions. An asymmetric four -grating compressor (AFGC) based multistep pulse compressor method was proposed recently to alleviate the requirement of such gratings. The viability of AFGC is further investigated experimentally in SEL -100 PW frontend with spectral bandwidth of over 200 nm in this study. It is verified that the AFGC has the ability of beam-smoothing resulting from the introduced spatial dispersion. Meanwhile, the spatial dispersion scarcely impacts temporal contrast and focal spot of the output beam. By reducing the laser spatial intensity modulations from 2.0 to 1.3, the pulse energy capacity of the AFGC can be increased by more than 1.5 times through simple translation. The results mark a breakthrough toward experimentally renovating the grating compressor, and pave the way for a reliable and efficient constructions of 100 s PW lasers.