In order to achieve accurate superposition of array lasers in the far field and ensure the quality of the array laser synthetic beam, it is required that the array laser sub-beams point in the same direction, i.e., there is no tilt aberration between the sub-beams. To this end, a composite sensing-based array laser tilt detection and correction method is proposed, which combines single-lens detection with microlens array detection and can achieve large dynamic range, high accuracy and high bandwidth correction to a certain extent. The basic principle of the method is: for the large dynamic range of the array laser first use microlens detection and stochastic parallel gradient descent algorithm (SPGD) for coarse correction, when the array laser sub-beam into the microlens array range, use microlens detection and PI control combined to achieve fast and high precision correction of the array laser tilt aberration. The tilt correction effect of the composite sensing-based array laser tilt correction method is compared with that of the SPGD control algorithm alone and the PI control algorithm alone, and the results show that the iteration efficiency of this method is 3.5 times higher than that of the SPGD algorithm alone for the same tilt correction results, and the synthetic beam quality is significantly improved after the tilt correction. The composite sensing-based array laser tilt aberration correction solves the contradiction between large dynamic range and high accuracy and high bandwidth to a certain extent without significantly increasing the system complexity, and effectively improves the anti-jamming ability and environmental adaptability of the array laser, which has great potential and promising application.
When adaptive optics is applied to target identification, laser high beam quality transmission and other fields, extended object wavefront detection is a technical challenge. And the detection accuracy directly affects the adaptive optics correction effect. To investigate the problem that the focal length of microlens affects the accuracy of extended target wavefront detection. In this paper, a simulation model of extended target wavefront detection based on correlated Hartmann's variable focus was established. The model was based on the commonly used optical system parameters, and it was also established by using the theories of Fresnel diffraction, Newton's imaging equation, the working principle of Shack-Hartmann wavefront detector, and wavefront reconstruction. We analyzed the effect of microlens focal length variation on the wavefront detection accuracy. The relationship curves between the wavefront reconstruction residuals RMS, PV and microlens focal length were obtained. And we further analyzed the intrinsic physical reasons for this relationship.The results show that the variation of the microlens focal length affected the point spread function used in the algorithm.The smaller the focal length, the more accurate the corresponding point spread function calculation results. Therefore, the smaller the calculation error of the subaperture offset, the higher the wavefront detection accuracy.
When adaptive optics is applied to target imaging, laser atmospheric transmission, etc., variable extension target wavefront detection is a technical challenge. And its detection accuracy directly affects the correction effect of adaptive optics.In order to explore the wavefront detection accuracy problem of variable extension targets. In this paper, a simulation model for wavefront detection of variable extension targets with correlated Hartmann was developed. The model was based on the commonly used optical system parameters, and it was also established by using the theories of Fresnel diffraction, Newton's imaging equation, the working principle of Shack-Hartmann wavefront detector, and wavefront recovery.We analyzed the effects of target distance and attitude variations on wavefront detection accuracy. The relationship curves between RMS and PV of wavefront recovered residuals and target distance and different attitudes were obtained in the simulation. And we further carried out the analysis for the intrinsic physical reasons of forming this relationship. The results show that target distance and attitude changes affected the extension of targets within the Hartmann subaperture. When the wavefront was recovered using the correlation algorithm, we obtained that the smaller the extension, the higher the wavefront detection accuracy within the relevant Hartmann detection accuracy. Therefore, it could be summarized that the smaller the extension of the target, the more similar it was to the point target, then the detection error introduced by the extension became smaller.
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