High resolution residual wavefront reconstruction for closed-loop adaptive optics systems

摘要

High-resolution imaging with large ground-based telescope is challenging due to atmospheric turbulence. Adaptive optics (AO) system can provide real-time compensation for the wavefront distortion in the pupil of the telescope. However, the observed images still suffer from a blurring caused by the residual wavefront. Numerical post-processing with a good approximation of the residual wavefront can help to effectively remove the blur. In this paper, a gradients measurement model for the Shack-Hartmann wavefront sensor (WFS) in a closed-loop AO system is built. The model is based on the frozen flow hypothesis with knowledge of the wind velocities of atmospheric turbulence layers. Then a high resolution residual wavefront reconstruction method using multiframe Shack-Hartmann WFS measurements and dcformable mirror voltages is presented. Numerical results show that the method can effectively improve the spatial resolution and accuracy of the reconstructed residual wavefront.