Optimization of the temporal performance of a deformable mirror for use in ophthalmic applications

Abstract

Adaptive optics (AO) is used to correct wavefront aberrations in light in real-time. An AO system is principally made up of three parts; a wavefront measuring device, a correction device, and a control algorithm to compute the residuals between the measured and a reference wavefront. Deformable mirrors (DM) are commonly used as the correction devices in such a system. This paper presents a method to improve a DM's temporal performance by attenuating parasite oscillations of its reflective membrane when applying high-frequency signals to the mirror actuators. The method consists of implementing low-pass filtering into the software driving the mirror. Different filtering functions were studied both when stimulating one single actuator, and when applying voltages to the complete array of actuators. A linear decomposition in 41 substeps showed the best performance for all considered configurations. The obtained results represented an important reduction of the settling time as well as the overshoot of the signal response.