Efficient wavefront sensorless adaptive optics based on large dynamic crosstalk-free holographic modal wavefront sensing.

Abstract

The correction of wavefront sensorless adaptive optics (WFSless AO) can be significantly accelerated by using a holographic modal wavefront sensor (HMWFS). The HMWFS is realized by a computer-generated hologram (CGH) into which all aberration modes to be detected are encoded and only a single-shot image is required for simultaneous measurement of multiple modes. The conventional HMWFS suffers from a quite limited dynamic range and severe inter-modal crosstalk which deteriorates the sensing accuracy. We proposed a novel HMWFS with a large dynamic range and no crosstalk and validated its performance by simulation and experiment. In the improved HMWFS scheme, the aberration is represented by Lukosz modes whose gradients are orthogonal and the modal coefficients can be estimated independently. Instead of using a binary CGH in conventional HMWFS, a kinoform CGH with high diffraction efficiency is adopted in the improved HMWFS. The kinoform CGH is produced by a phase-only liquid-crystal spatial light modulator (LCSLM) which also serves as a wavefront corrector in our WFSless AO system.