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