AAS 203rd Meeting, January 2004
Session 3 Space Missions: Planet Finding, Astrobiology and Others
Poster, Monday, January 5, 2004, 9:20am-6:30pm, Grand Hall

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[3.02] Wavefront Estimation and Control Algorithms for High-Contrast Imaging

A. Give'on, L. Pueyo, N.J. Kasdin, M.G. Littman, R.J. Vanderbei (Princeton University)

The ultimate limitation of high-dynamic-range imaging systems is the residual scatter due to imperfections in the optical surfaces and the non-uniform reflectivity of those surfaces. The first step in correcting the wavefront errors from scattering is the estimation of the phase aberrations. Its parameters are estimated using a global search with a genetic algorithm and a local optimization with the BFGS quasi-Newton method with a mixed quadratic and cubic line search procedure. Assuming one uses a deformable mirror to correct these aberrations, we propose an algorithm that optimally decreases the scattering level in specified localized areas in the image plane independent of the influence function of the deformable mirror. The amplitude aberration induced by the reflectivity errors can be corrected by the means of a Michelson interferometer in conjunction with two deformable mirrors. We present an experimental proof of such a monochromatic closed loop amplitude control. We gratefully acknowledge the support of the Jet Propulsion Laboratory of the National Aeronautics and Space Administration for this work.

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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.