HIGH-CONTRAST, NARROW-FIELD EXOPLANET IMAGING WITH A MULTI-APERTURE TELESCOPE PHASED-ARRAY CORONAGRAPH

The coronagraphic imaging of nearby solar systems with a densely packed array of small, inexpensive collector telescopes is considered. A reduced-scale segmented pupil can be assembled downstream of the collectors either by means of an array of delay lines, or more conveniently, by means of an array of single-mode fibers. In either case, the individual pupil elements are completely decoupled from each other. Tuning the intensity and phase of the light in each pupil element then allows complete control over the pupil-plane field, thus enabling arbitrary and tunable complex pupil-plane apodization. Calculations show that such a "phased-array coronagraph" (PAC) can in principle provide the 10(-10) image-plane contrast required for terrestrial exoplanet observations near bright stars. A PAC may thus provide a route to coronagraphic observations of faint exoplanets that is both flexible and potentially relatively inexpensive.