<title>Adaptive optics using curvature sensing</title>

Abstract

An adaptive optics scheme is proposed which uses curvature sensing, a bimorph PZT deformable mirror, a simple extrafocal image splitter and a sensitive, low noise Solid State Photomultiplier array detector. With curvature sensing, the incoming wavefront is described in terms of curvature which can be directly mapped point-by-point to a driven deformable segmented mirror. While other methods such as Hartmann, require time and cost consuming computations, the curvature mirror can be driven in near real-time taking full advantage of the 11 kHz bandwidth of the bimorph mirror. The SSPM is easily configured to any array pattern without loss of performance. The arrangement is particularly suited to large telescopes in the 8 m class for which the wavefront curvature sensor can provide additional useful information to correct for collimation and structural variations as well as the rapid seeing correction.