Simulation analysis of new wavefront reconstruction method for large aperture laser beam

Abstract

Laser beam propagation in the atmosphere is inevitably affected by turbulence and extinction, the far-field intensity distribution of the spot changes greatly relative to the laser exit. When the beam quality parameters are measured by the traditional method, the atmospheric effect is difficult to remove and the analysis mechanism is complex. Since the Hartmann-Shack wavefront sensor can detect the wavefront phase of the laser beam. The far-field situation of laser beam can be obtained by processing the phase information of near-field, which can be applied to the diagnosis of laser beam quality. However, for the wavefront distribution of large aperture spot, especially the wavefront distribution of high power laser, the traditional Hartmann-Shack wavefront detection method is no longer applicable due to the limitation of aperture size and the anti-damage detection threshold of detection components. In this paper, a wavefront direct measurement system based on Hartmann detection principle is proposed, which can measure large aperture and high power laser beam. The simulation results show that the wavefront recovery error of our method is low in a large detection range. The performance of this method is also evaluated on a more complex wavefront, and the wavefront recovery accuracy is lower than 0.20λ. The system proposed in this paper is suitable for large aperture laser beam measurement. It is of great importance to improve the measurement accuracy of beam quality.