Digital fast correction of wavefront distortion in active imaging with coherent light illumination

Considering the wavefront aberration in active imaging with coherent light illumination and spatial heterodyne detection, a digital fast correction technique was proposed. An experimental setup was established, and the target scattering optical complex amplitude on the detection aperture was divided into four sub regions through the numerical segmentation. The high order aberrations in the sub regions were corrected in parallel with tochastic parallel gradient descent algorithm, and then the piston, tip and tilt wavefront aberration among the sub regions were corrected in parallel. The experimental results show that, 600 iterations is needed when the stochastic parallel gradient descent algorithm is used directly, while only 100 iterations is needed for this method proposed in the paper, and the amount of computation is smaller, so that the efficiency of correction is greatly improved.