Characterization of close-loop performance of double drive modes unimorph deformable mirror

摘要

Unimorph deformable mirrors are attractive in adaptive optics system due to their advantages of simplicity, compact, low cost and large stroke. In this paper, a double drive modes unimorph deformable mirror is discussed, which comprises a 100 μm thick PZT layer and a 200 μm thick silicon layer. This deformable mirror (DM) can achieve two different directions deformation of concave and convex driven by only positive voltage. The dual direction maximum defocus deformations are -14.3 μm and 14.9 μm. The close-loop performance of this DM is also tested in an experimental adaptive optics system based on Hartman-Shack wavefront sensor. In experiments, the DM is controlled by the steepest descent algorithm (SD) to corrected the aberrations in a close-loop manner. The ability of this DM of correction for the system aberration and reconstruction for the low order Zernike mode aberration is tested. The root mean square (rms) value of the system aberration after close-loop correction is about 28 nm. The reconstruction results for most low order Zernike mode aberrations have a relative error less than 10%.