Optical verification of occulter-based high contrast imaging

Abstract

An external occulter precisely flown in formation with a space telescope has been recently studied as a mission scenario for direct imaging of exoplanets. 10-10 contrast must be attained to permit imaging of the faint reflected light of an Earth-like exoplanet. Here we report on experimental verification of a scaled occulter design that maintains a constant Fresnel number to an equivalent 400 mas space mission in monochromatic light at 632 nm using a diverging beam and an outer mask to suspend the occulter mask. We report contrast in regions of the discovery zone at 4.71 × 10-10 and suppression in the pupil plane of 3.7 × 10-7. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).