Lightweight Deformable Mirror Systems

In this project, a lightweight membrane mirror device will be integrated into an adaptive control system, capable of correcting static and dynamic primary-mirror shape errors in a space-based telescope. The core innovation will be the use of a multi-zone, deformable mirror fabricated by thin-film surface micromachining. Contour shape of the mirror membrane will be controlled by an array of electrostatic actuators, each of which can deform a local subaperture. Electrostatic actuation holds considerable promise for membrane mirror shape control because it offers nearly reversible (i.e. low power) actuation, no hysteresis, and nanometer-scale precision and repeatability. Prototype micromachined deformable mirror (¿DM) devices show promise: they are one hundred times faster, one hundred times smaller, and consume ten thousand times less power than the commercially available macroscopic DMs. The project team has produced the first continuous membrane zone-controlled ¿DMs: a critically important step in the development of large-aperture, space-based, lightweight mirror systems. Core research areas to be addressed in this project include development of optical thin-film reflective coatings for ¿DM membranes, demonstration of feasibility of a ¿DMs in a closed loop adaptive optical system, and design improvements to ¿DMs to allow more actuators, larger apertures, and curved substrates. ~990060 ~