Dual Wavefront Sensor Adaptive Optics System

Recent developments in MEMS-based deformable mirrors offer improved performance for adaptive optics (AO) systems. However, because of current limitations in wavefront sensing and processing, these performance gains have been largely unexploited. To address this need, we propose building an AO system with dual wavefront sensing techniques. The heart of the system is a novel optically addressed MEMS-on-VLSI spatial phase light modulator that also performs a key part of the wavefront phase computation. The two wavefront sensors serve as complementary backups and provide accurate wavefront correction data over a variety of conditions. One of the wavefront sensors uses a Hartmann-Shack sensor, directly integrated with an on-chip analog wavefront processor and deformable mirror. The analog wavefront processor uses massively parallel on-chip computation and is expected to solve the wavefront difference equations in hundreds of nanoseconds. The second wavefront system is based on dithered optimization of the image sharpness function. This approach leverages the high pixel refresh rates (>160 kHz) of the DM, and systematically arrives at an optimal solution. Combined with Optron's large-stroke MEMS deformable mirror technology, this AO system will be capable of 8µm of phase modulation (16µm in reflection), have greater than 8-bits of phase resolution, and potentially tens of thousands of pixels.