In-house beam-splitting pulse compressor for high-energy petawatt lasers.

One of the most significant bottlenecks in achieving kilojoule-level high-energy petawatt (PW) to hundreds-petawatt (100PW) lasers is the requirement of as large as meter-sized gratings so as to avoid the laser-induced damage in the compressor. High-quality meter-sized gratings have so far been difficult to manufacture. This paper proposes a new in-house (intra-) beam-splitting compressor based on the property that the damage threshold of gratings depends on the pulse duration. The proposed scheme will simultaneously improve the stability, save on expensive gratings, and simplify compressor size because the split beams share the first two parallel gratings. Furthermore, as the transmitted wavefront of a glass plate can be better and more precisely controlled than the diffraction wavefront of a large grating, we propose glass plates with designed transmitted wavefront to compensate for the wavefront distortion introduced by the second and third gratings, and other in-house optics, such as the beam splitter. This simple and economical method can compensate for the space-time distortion in the compressor, and thus improve focal intensity, which otherwise cannot be compensated by a deformable mirror outside the compressor. Together with a multi-beam tiled-aperture combining scheme, the proposed novel compressor provides a new scheme for achieving high-energy PW-100PW lasers or even exawatt lasers with relatively small gratings in the future.