We compare the broadband contrast performances of several Phase Induced Amplitude Apodization (PIAA) coronagraph configurations through modeling and simulations. The basic optical design of the PIAA coronagraph is the same as NASA’s High Contrast Imaging Testbed (HCIT) setup at the Jet Propulsion Laboratory (JPL). Using a deformable mirror and a broadband wavefront sensing and control algorithm, we create a 'dark hole' in the broadband point-spread function (PSF) with an inner working angle (IWA) of 2(fλ/D)_sky. We evaluate two systems in parallel. One is a perfect system having a design PIAA output amplitude and not having any wavefront error at its exit-pupil. The other is a realistic system having a design PIAA output amplitude and the measured residual wavefront error. We also investigate the effect of Lyot stops of various sizes when a postapodizer is and is not present. For the configurations simulated here with the first-generation PIAA mirrors, the best 7.5% broadband contrast value was ~1.5×10^-8.

Date Published: 26 September 2013
PDF: 11 pages
Proc. SPIE 8864, Techniques and Instrumentation for Detection of Exoplanets VI, 88641Y (26 September 2013); doi: 10.1117/12.2035237

Published in SPIE Proceedings Vol. 8864:
Techniques and Instrumentation for Detection of Exoplanets VI
Stuart Shaklan, Editor(s)