Compact compressor based on unparallel gratings

Abstract

The pulse compressor is one of the essential components in a high-power laser system, which is often bulky. Here, we propose a compact compressor based on a Treacy compressor with two unparallel gratings and a mirror. Two gratings provide a negative group delay dispersion, and the mirror has two functions. One is to make the beam enter the compressor twice, and the other is to make the optical path between the grating pair folded to reduce the volume of the compressor. The relation between the group delay dispersion and the incident angle in three-dimensional space is derived. The results show that a small spatial incident angle can produce a large negative dispersion when the perpendicular distance between the gratings is the same. The parameter limits of the designed structure are also discussed, and the volume of compact compressor under the simulated parameters is two-thirds of the conventional compressor when the constraints are satisfied. This work is applicable to the optimal design of grating-based compressors with different parameters.