Real-time restoration of a blurred image with a liquid-crystal adaptive-optics system based on all-optical feedback interferometry

Real-time restoration of a blurred image using an all-optical adaptive-optics system with a liquid-crystal (LC) device is described. This system is based on a feedback interferometer, where the two-dimensional output fringe intensity from a Mach-Zehnder interferometer with large radial shear is optically fed back to an optically addressed phase-only LC spatial light modulator (SLM). In operation the phase of the reflection-type modulator approximates to half of the conjugate of the input aberrated wave front without a separate aberration-free reference wave. We applied this system to a problem of imaging through a phase-distorting medium and observed that an image blurred by the phase disturbance was restored immediately after the feedback loop was closed. In this case the response time and the resolution of the SLM were about 60 ms and 40 line pairs/mm, respectively. (C) 2001 Elsevier Science B.V. All rights reserved.