Multiplexed wavefront sensing using a grating array-based wavefront sensor

This paper addresses the ambiguity problem associated with a periodic array of spots in the Shack-Hartmann wavefront sensor (SHWS) when used for multiplexed wavefront sensing, corresponding to multiple isoplanatic patches. We overcome this issue by introducing a multiplexed wavefront sensing scheme, utilizing a grating array-based wavefront sensor that is a programmable version of SHWS. Three beams representing lights from three distinct guide stars are generated to validate the proposed scheme. Each beam passed through different regions of a pseudo-random phase plate, resulting in different random phases that mimic turbulence effects. We detected three wavefronts from a single frame of data by employing a binary phase grating array on a spatial light modulator at the pupil plane. The proposed sensing scheme is compatible with existing wavefront reconstruction algorithms. This study has potential applications in multi-conjugate adaptive optics, where multiple wavefront sensors are needed to detect various isoplanatic patches in order to expand the field of view in turbulent conditions.