Abstract

Very high-order zonal adaptive optics systems based on measuring the subaperture tilts using a Hartmann-Shack wavefront sensor suffer from increased hardware complexity and much greater computational burdens associated with centroid estimation and reconstructing the phase in real time. There is interest in developing practical wavefront sensors using non-interferometric techniques based entirely on intensity measurements [1]. Phase retrieval for wavefront sensing can make use of one or more intensity measurements with a known phase offset between multiple images. Phase recovery techniques are generally nonlinear and iterative [2], possibly prone to stagnation regimes, and have been the limiting factor in making real time intensity based wavefront sensors a reality. Herein we demonstrate that under the assumption of small phase and phase offsets between intensity measurements that an exact expression can be derived to recover the phase if three or more images are used.

© 1998 Optical Society of America