Simulation Analysis of a Wavefront Reconstruction of a Large Aperture Laser Beam

Abstract

In order to solve the problem of atmospheric influence on the far-field measurement of the quality of a laser beam, we proposed a direct wavefront measurement system based on the Hartmann detection principle, which can measure large apertures and high-power laser beams. The measuring system was composed of a lens array and a detector. The wavefront detection of a large aperture laser beam could be realized by controlling the distance between the lenses and the size of the lens. The influence of different duty cycle factors on the accuracy of the wavefront reconstruction under the same arrangement and different arrangement conditions was simulated and analyzed. The simulation results showed that when the sub-lenses of the system were not in close contact, the reconstruction accuracy of the duty factor of 0.8 was close to that of the case of the duty factor of 1. Within a certain detection range, the hexagonal arrangement of 19 lenses and the arrangement of 8 × 8 lens arrays had a high wavefront restoration accuracy; both were lower than 0.10 λ. The system proposed in this paper was suitable for measuring a large aperture laser beam, providing a new idea for measuring and analyzing the quality of large aperture laser beams. It also has an important significance for improving the measurement accuracy of the beam quality.

Simulation Analysis of an Atmospheric Turbulence Wavefront Measurement System

“…Under the same arrangement, the wavefront reconstruction accuracy of the system increases with the increase in the duty factor of the lens array. When the duty factor of the lens array is about 0.8, the wavefront reconstruction accuracy of the system is moderately different from that obtained when the duty factor of the lens array is 1 [28]. On the premise of using the smallest lens size combination to detect the largest distortion wavefront, we chose a duty factor of the system lens array of 0.8.…”

Expanded Scene Image Preprocessing Method for the Shack–Hartmann Wavefront Sensor

“…To handle the image noise, we utilize residual feedback for block-matching and 3D filtering (BM3D). Additionally, we perform offset computation using the normalized intercorrelation algorithm [24] to achieve wavefront reconstruction [25].…”

Influence of Image Processing Method on Wavefront Reconstruction Accuracy of Large-Aperture Laser

“…The beam quality of large-aperture lasers is difficult to measure directly. Therefore, the laser at the exit of the system can be measured by constructing a lens array suitable for the laser beam size, so as to obtain the beam quality parameters [1][2][3]. In the practical application scene, due to the influence of ambient light, detector noise, and other factors, the sub-aperture spot intensity distribution in the spot image collected using the detector array is uneven [4,5], which leads to a decrease in spot centroid positioning accuracy, thus affecting the wavefront reconstruction accuracy and beam quality parameter measurement accuracy [6][7][8].…”