Object-oriented wavefront correction in an asymmetric amplifying high-power laser system

Abstract

An object-oriented wavefront control method is proposed aiming for excellent near-field homogenization and far-field distribution in an asymmetric amplifying high-power laser system. By averaging the residual errors of the propagating beam, smaller pinholes could be employed on the spatial filters to improve the beam quality. With this wavefront correction system, the laser performance of the main amplifier system in the Shen Guang-III laser facility has been improved. The residual wavefront aberration at the position of each pinhole is below 2 µm (peak-to-valley). For each pinhole, 95% of the total laser energy is enclosed within a circle whose diameter is no more than six times the diffraction limit. At the output of the main laser system, the near-field modulation and contrast are 1.29% and 7.5%, respectively, and 95% of the 1ω (1053 nm) beam energy is contained within a 39.8 µrad circle (6.81 times the diffraction limit) under a laser fluence of 5.8 J cm−2. The measured 1ω focal spot size and near-field contrast are better than the design values of the Shen Guang-III laser facility.

Research on spatial filter lens auxiliary adjustment system in high power laser facility

“…Theoretically, the two ends of the lens need to be adjusted in five dimensions. At present, with the array design of laser devices, such as the spatial filter of 2x4 array [16][17][18] , the eight optical axes still need to maintain certain parallelism and coaxiality, which also puts forward higher requirements for the debugging method.…”