High contrast imaging wavefront sensor referencing from coronagraphic images

A key challenge of high contrast imaging (HCI) is to differentiate a speckle from an exoplanet signal. The sources of speckles are a combination of atmospheric residuals and aberrations in the non-common path. Those non-common path aberrations (NCPA) are particularly challenging to compensate for as...

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Published inarXiv.org
Main Authors Skaf, Nour, Guyon, Olivier, Boccaletti, Anthony, Deo, Vincent, Vievard, Sebastien, Lozi, Julien, Ahn, Kyohoon, Norris, Barnaby, Currie, Thayne, Gendron, Eric, Bertrou-Cantou, Arielle, Ferreira, Florian, Sevin, Arnaud, Vidal, Fabrice
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 28.10.2021
Subjects
Algorithms
Coronagraphs
Extrasolar planets
Image contrast
Optimization
Sensors
Wave front sensors
Wave fronts
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Summary:A key challenge of high contrast imaging (HCI) is to differentiate a speckle from an exoplanet signal. The sources of speckles are a combination of atmospheric residuals and aberrations in the non-common path. Those non-common path aberrations (NCPA) are particularly challenging to compensate for as they are not directly measured, and because they include static, quasi-static and dynamic components. The proposed method directly addresses the challenge of compensating the NCPA. The algorithm DrWHO - Direct Reinforcement Wavefront Heuristic Optimisation - is a quasi-real-time compensation of static and dynamic NCPA for boosting image contrast. It is an image-based lucky imaging approach, aimed at finding and continuously updating the ideal reference of the wavefront sensor (WFS) that includes the NCPA, and updating this new reference to the WFS. Doing so changes the point of convergence of the AO loop. We show here the first results of a post-coronagraphic application of DrWHO. DrWHO does not rely on any model nor requires accurate wavefront sensor calibration, and is applicable to non-linear wavefront sensing situations. We present on-sky performances using a pyramid WFS sensor with the Subaru coronagraph extreme AO (SCExAO) instrument.
ISSN:2331-8422