Low-order wavefront control using a Zernike sensor through Lyot coronagraphs for exoplanet imaging

Context. The combination of large segmented space telescopes, coronagraphy, and wavefront control methods is a promising solution for producing dark hole (DH) region in the coronagraphic image an observed star order to study planetary companions. thermal mechanical evolution such high-contrast instrumental setup leads drifts that degrade DH contrast during observing time, thus limiting ability retrieve signals. Aims. Lyot-style coronagraphs are starlight-suppression systems remove central part unresolved star, is, point spread function, with opaque focal plane mask (FPM). When implemented flat mirror containing etched pinhole, rejects starlight through pinhole which can be used information about low-order aberrations. Methods. We propose active scheme using Zernike sensor (ZWFS) analyze light rejected by FPM, aberrations, stabilize contrast. first present concept formalism then describe how we characterized behavior simulations laboratory. performed experimental tests validate loop ZWFS on HiCAT testbed. Results. By controlling 11 modes, show decrease standard deviation error factor up 9 between open- closed-loop operations ZWFS. In presence perturbations, this around 7 × 10 −8 −9 . Conclusions. Active proves Lyot FPM-filtered beam stabilizing aberrations exoplanet imaging future missions.