Progress in Technology Advancement of Multi-Star Wavefront Control for Exoplanet Imaging

We present the continued progress and laboratory results advancing the technology readiness of Multi-Star Wavefront Control (MSWC), a method to directly image planets and disks in multi-star systems. This method works with almost any coronagraph (or external occulter with a DM) and requires little or no change to existing and mature hardware. In particular, it works with single-star coronagraphs and does not require the off-axis star(s) to be coronagraphically suppressed. Because of the ubiquity of multistar systems, this method increases the science yield of many missions and concepts such as Roman, Exo-C/S, HabEx, LUVOIR, and potentially enables the detection of Earth-like planets (if they exist) around our nearest neighbor star, Alpha Centauri, with a small telescope, in addition to larger missions. We report on several lab demonstrations of MSWC, including demonstrations at the Ames Coronagraph Experiment (ACE) laboratory with the PIAA and classical Lyot coronagraphs, as well as with the SCExAO instrument using an internal source, and preliminary demonstrations in vacuum at the Decadal Survey Testbed (DST) at JPL. Our light source at ACE and SCExAO can move to simulate two sources with variable separation and brightness difference, representing real binary stars. Our demonstrations include both sub- and super-Nyquist versions of MSWC, showing that active suppression of light from a binary is possible even when the star separation exceeds the outer working angle of the deformable mirror. As a control experiment, we use standard single-star speckle suppression techniques in our experiment and quantify the gains enabled by using MSWC. Our preliminary vacuum demonstrations on DST include 4e-8 contrast in monochromatic light and 4e-7 in broadband light, using single-star super-Nyquist mode, retiring one of the key risks in MSWC.