Abstract
Abstract: :
Purpose: A breadboard test model of a closed loop adaptive optics system was implemented to evaluate the correction capability of an OKO 37–channel deformable mirror. The main goal was to investigate low–order correction capability of the mirror for adaptive optics applications in vision science. Methods: A Hartmann sensor was used to sample the wavefronts and a commercial software was used for closed loop control of the mirror. Combinations of spherical and cylindrical ophthalmic test lenses were used to produce distorted wavefronts to be corrected by the deformable mirror. An open loop solution was also implemented to evaluate the mirror’s capability of reproducing wavefronts containing single Zernike coefficients (up to fifth order). Results: The mirror could adequately correct (Strehl ratio > 0.8) approximately ± 2.25D of pure spherical refractive power and approximately ± 1.25D of pure cylindrical refractive power. The capability of reproducing a certain Zernike coefficient decreases with increasing term order and for a Strehl ratio of 0.6, from about ± 0.8 µm for third order to about ± 0.4 µm for fifth order. In addition, terms with a monotonically increasing radial part were easier to reproduce than terms with multiple maxima or minima. Conclusions: The correction performance of cylindrical wavefronts is better in the horizontal orientation than in the vertical orientation, a result of the mirror actuator geometry. The mirror is slightly better at correcting/reproducing wavefronts with positive dioptric power. Although the OKO mirror has a limited dynamic range it is quite capable of removing residual lower order aberrations in an adaptive optical system.
Keywords: optical properties