Wide Field Scanning Telescope using MEMS Deformable Mirrors

Traditional optical telescopes can obtain high resolution images, but only over a narrow field of view. To image over a large field, the typical approach is to move the entire telescope to point to a particular area of interest. In this article, we consider a scanning telescope that only moves one of the optical elements in the telescope. Moving the lower inertia of a single optical element instead of the entire telescope means faster scanning, reduced vibration, and more accurate pointing. Inherent in the design is the introduction of optical aberrations due to off-axis imaging. This article presents simulation and experimental results of using deformable mirrors to correct for the off-axis aberrations. Two different types of deformable mirrors are considered: electrostatic and electromagnetic. The mirror apertures are similar in size, but the electromagnetic mirror has about twice the actuator displacement range than the electrostatic mirror. Through simulation and experiments, we demonstrated that the static field of view may be increased by 40 times with the electrostatic mirror and 80 times with the electromagnetic mirror.