Coronagraphy for segmented apertures: Results from demonstrations on the HICAT testbed

Achieving high contrast on segmented, obscured apertures requires the combination of state-of-the-art wavefront control with coronagraph designs carefully optimized for segmented apertures. The Apodized Pupil Lyot Coronagraph (APLC) architecture has emerged as a promising approach, as apodizer shapes can be tailored to any arbitrary pupil geometry, and optimized to maximize science yield while varying constraints such as required inner working angle. Our team has been testing such apodizers, fabricated with carbon nanotubes on silicon and silver substrates, on the High-contrast imager for Complex Aperture Telescopes (HiCAT) testbed. As part of our overall full-system investigation into high contrast on segmented apertures, we have also been assessing performance of several strategies for image-based wavefront sensing on the obscured APLC pupils, and developing numerical models for contrast error budgeting. In this poster we present the latest updates on performance results with APLC coronagraphy from the HICAT testbed, as part of our ongoing TDEM technology program.