Characterization of large deformable mirrors

A key element in any adaptive optics (AO) system is the deformable mirror used to introduce the conjugate correction. In this paper we will present the results from characterizing a pair of custom 20 element, 38 min diameter, bimorph deformable mirrors that were specifically designed to provide unusually large stroke to allow correction of significant focus and astigmatism terms in a human fundus AO imager. Data on the measured correction capability and inherent hysteresis of the mirror shown that the mirrors have 40 gm waves of defocus correction and 20 gm waves of astigmatism correction at 760 nm, with a typical hysteresis at full deflection of 15%. This technology is patented under Patent 6,331,059 B 1.