Wavefront Reconstruction of Shack-Hartmann with Under-Sampling of Sub-Apertures

Shack-Hartmann wavefront sensor plays a key role in adaptive optics (AO) systems, which detect the aberrant wavefront by an array of micro-lenslets across the aperture pupil. However, some sub-apertures would be a lack of light induced by the imperfectness of micro-lenslets or pupil shift away from the optical path. Thus, the wavefront detection would be under-sampled and the performance of wavefront reconstruction would be severely degraded. It is therefore important to evaluate the influence of under-sampling on the wavefront reconstruction. In this paper, an AO system was established by the OOMAO simulation platform. For dynamical turbulence aberrations or statistic defocus aberrations, three cases including a single sub-aperture, a row of sub-apertures, and a quadrant sub-apertures lack of light were simulated. Compared with the uncorrected aberrant wavefront, our results showed that the RMS of the residual wavefront for a typical atmospheric condition (Fried parameter (r(0)) ranges from 5 cm to 15 cm) can be reduced by a factor of 5 similar to 8, 4 similar to 6, and 2 similar to 3 with these three cases of under-sampling, respectively.

Automated summary

The Shack-Hartmann wavefront sensor is crucial in adaptive optics systems for detecting aberrant wavefronts. However, under-sampling due to imperfect micro-lenslets or pupil shift can lead to degraded wavefront reconstruction. This study evaluates the impact of under-sampling on wavefront reconstruction using an AO system simulation.