29 July 2016 Coronagraphic wavefront sensing with COFFEE: high spatial-frequency diversity and other news
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The final performance of current and future instruments dedicated to exoplanet detection and characterization is limited by intensity residuals in the scientific image plane, which originate in uncorrected optical aberrations. In order to reach very high contrasts, these aberrations needs to be compensated for. We have proposed a focalplane wave-font sensor called COFFEE (for COronagraphic Focal-plane wave-Front Estimation for Exoplanet detection), which consists in an extension of conventional phase diversity to a coronagraphic system. In this communication, we study the extension of COFFEE to the joint estimation of the phase and the amplitude in the context of space-based coronagraphic instruments: we optimize the diversity phase in order to minimize the reconstruction error; we also propose and optimize a novel low-amplitude high-frequency diversity that should allow the phase-diverse images to still be used for science. Lastly, we perform a first experimental validation of COFFEE in the very high, space-like contrast conditions of the THD bench and show that COFFEE is able to distinguish between phase and amplitude aberrations.
© (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
L. M. Mugnier, L. M. Mugnier, J.-F. Sauvage, J.-F. Sauvage, O. Herscovici-Schiller, O. Herscovici-Schiller, P. Baudoz, P. Baudoz, R. Galicher, R. Galicher, J.-M. Le Duigou, J.-M. Le Duigou, "Coronagraphic wavefront sensing with COFFEE: high spatial-frequency diversity and other news", Proc. SPIE 9904, Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave, 99043A (29 July 2016); doi: 10.1117/12.2233726; https://doi.org/10.1117/12.2233726

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