Adaptive control in an adaptive optics experiment with simulated turbulence-induced optical wavefronts

Abstract

This paper presents results from an adaptive optics experiment in which an adaptive control loop augments a classical adaptive optics feedback loop. A membrane deformable mirror is used for wavefront correction, and a set of frequency-weighted modes based on the actuator geometry are used to define the control channels for the adaptive controller. In the adaptive optics experiment, the wavefront sensor in the control loop is a three step phase shifting self-referencing interferometer. The corrected laser beam is imaged by a diagnostic CCD camera. The effect of atmospheric turbulence is simulated in the experiment by a sequence of wavefronts that is generated by a WaveTrain adaptive optics model and added to the laser beam by a spatial light modulator. The experimental results show the improved closed-loop wavefront errors and diagnostic images produced by the adaptive control loop as compared to the classical adaptive optics loop.