Shaped pupil Lyot coronagraph designs for WFIRST/AFTA

Abstract

© 2015 SPIE.The baseline design for the WFIRST-AFTA Coronagraphic Instrument includes several shaped pupil masks. Our newest designs incorporate the shaped pupil into a Lyot-style architecture to access smaller inner working angles at a given tradeoff in throughput and contrast. We describe two mask configurations: a characterization mode for spectroscopy of exoplanet atmospheres, and a wider-field mode for debris disk observations. We use polychromatic contrast constraints to anchor the spatial extent of the dark search region over the instrument filter bandpass. We examine several practical issues that arise during the optimization process, such as the use of symmetry, and the choice of spatial and wavelength resolutions in the propagation model. Finally, we evaluate the tolerances of the new designs to mask translation and clocking errors.