Wave front reconstruction using a second-order model for Shack-Hartmann wave front sensor measurements

摘要

Many adaptive optics systems rely on a Shack-Hartmann wave front sensor (WFS) coupled with a traditional least squares reconstructor to estimate the aberrations in the incident wave front. Unfortunately, the performance of this approach degrades in the presence of strong scintillation because, when there are intensity fluctuations in the wave front, the WFS does not measure the average phase gradient within each subaperture as assumed by the reconstruction algorithm. As scintillation increases, branch points in the wave front increase the disparity between what the WFS measures and what the reconstruction algorithm expects. A reconstruction algorithm is presented that attempts to mitigate the branch point problem by using a more realistic model for the Shack-Hartmann WFS measurements. Wave optics simulations over a variety of atmospheric conditions are used to compare the performance of this algorithm against a least squares reconstructor and a complex exponential reconstructor.