The phase grating wavefront curvature sensor based on liquid crystal spatial light modulator is introduced. A close-loop phase retrieval method based on Eigen functions of Laplacian is proposed, and its accuracy and efficiency are analyzed through numerical experiments of atmospheric phase retrieval. The results show that the close-loop phase retrieval method has a high accuracy. Moreover, it is stable regardless of modal cross coupling.
Considering the influences of speckle noises and wavefront aberration error on image quality in active imaging based on spatial heterodyne detection, a wavefront correction method that based on metric optimization of multi images is proposed, in which the multi images are generated by aperture dividing technique. An experimental setup is established, and the experiments that correcting the aberration of itself with the above method are performed, in which the stochastic parallel gradient descent algorithm and image sharpness function are used. The results show that the method of multi images averaging can be used to improve the signal-to-noise ratio of target image effectively, and a higher quality of target image can be achieved after correction by optimizing the image sharpness metric that generated with the averaging data of multi images.