Concept, modeling, and fabrication techniques for large-stroke piezoelectric unimorph deformable mirrors

Abstract

Large-stroke micromachined deformable mirror technology can boost the imaging performance of an otherwise non-rigid, lower-quality telescope structure. The proposed deformable mirror concept in this paper combines a microfabricated large-stroke piezoelectric actuator with a reflective membrane “transferred” in its entirety from a separate wafer. This process allows the large-stroke actuation of the continuous membrane and can provide the necessary large wavefront correction. The micromachined deformable mirror approach allows mass-production of actuators as well as scalable structures with, high actuator densities. The piezoelectric unimorph actuator design approach delivers large actuator stroke with a highly localized influence function, while maintaining a surface figure of optical quality. Both of these component fabrication techniques are easily scaled to accommodate deformable mirrors with very large areas.