Phase-induced amplitude apodization complex mask coronagraphy (PIAACMC) for large segmented apertures (Conference Presentation)

Abstract

High contrast imaging of exoplanets around nearby stars with future large segmented apertures requires starlight suppression systems optimized for such geometries, with the ability to control diffraction created by gaps between segments. The PIAACMC approach is well-suited for high high efficiency coronagraphic imaging of exoplanets at small angular separations, offering an inner working angle (IWA) as small as 1 lambda/D. We show that PIAACMC can be designed for segmented apertures and present a few representative designs. The design process can mitigate leaks due to stellar angular size and chromatic diffraction by segment gaps by co-optimizing a multi-zone diffractive focal plane mask and a Lyot stop. The resulting performance is ultimately limited by stellar angular size, and the IWA must be carefully traded against contrast and throughput at small angular separations. We show that PIAACMC's small IWA enables space-based near-IR imaging and spectroscopy of exoplanets around Sun-stars, and ground-based imaging and characterization of habitable planets around nearby M-type stars. We review the current status of PIAACMC laboratory development and near-term prospects for ground-based use.