Abstract: An adaptive optics system is provided, comprising a deformable mirror configured to receive an input beam with an aberrated wavefront and to reflect the input beam to a Shack-Hartmann wavefront sensor array. The system further comprises the Shack-Hartmann wavefront sensor array configured to receive the input beam from the deformable mirror, and to generate a plurality of sub-images from the input beam. The system further comprises a processor configured to measure, for each sub-image, two linear coefficients corresponding to a local wavefront aberration of the sub-image and to estimate, for each sub-image, three quadratic coefficients corresponding to the local wavefront aberration of the sub-image. The processor is further configured to reconstruct the aberrated wavefront of the input beam based on the measured linear coefficients and the estimated quadratic coefficients, and to provide control signals based upon the reconstructed wavefront to the deformable mirror to mitigate aberrations in the input beam.