Abstract

Large deformable mirrors, such as those envisioned for advanced space telescopes and the space laser program, will require a method for actively sensing the mirror figure while it is in use. Figure sensing is usually done at the center of curvature of the mirror; placing an interferometer at this point requires extending the telescope structure by many meters, which is not desirable because it introduces additional structural and packaging problems. There have been a variety of schemes presented in the past for figure sensing near the focal plane of the mirror. Of these schemes, the full aperture holographic zone plate studied by Erickson¹ is particularly attractive, since it provides full aperture phase information and does not require modifications of the mirror other than to the coating.

© 1982 Optical Society of America