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Closed-loop focal plane wavefront control with the SCExAO instrument

Martinache, Frantz and Jovanovic, Nemanja and Guyon, Olivier (2016) Closed-loop focal plane wavefront control with the SCExAO instrument. Astronomy and Astrophysics, 593 . Art. No. A33. ISSN 0004-6361. doi:10.1051/0004-6361/201628496.

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Aims. This article describes the implementation of a focal plane based wavefront control loop on the high-contrast imaging instrument SCExAO (Subaru Coronagraphic Extreme Adaptive Optics). The sensor relies on the Fourier analysis of conventional focal-plane images acquired after an asymmetric mask is introduced in the pupil of the instrument. Methods. This absolute sensor is used here in a closed-loop to compensate for the non-common path errors that normally affects any imaging system relying on an upstream adaptive optics system.This specific implementation was used to control low-order modes corresponding to eight zernike modes (from focus to spherical). Results. This loop was successfully run on-sky at the Subaru Telescope and is used to offset the SCExAO deformable mirror shape used as a zero-point by the high-order wavefront sensor. The paper details the range of errors this wavefront-sensing approach can operate within and explores the impact of saturation of the data and how it can be bypassed, at a cost in performance. Conclusions. Beyond this application, because of its low hardware impact, the asymmetric pupil Fourier wavefront sensor (APF-WFS) can easily be ported in a wide variety of wavefront sensing contexts, for ground- as well space-borne telescopes, and for telescope pupils that can be continuous, segmented or even sparse. The technique is powerful because it measures the wavefront where it really matters, at the level of the science detector.

Item Type:Article
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URLURL TypeDescription Paper
Martinache, Frantz0000-0003-1180-4138
Guyon, Olivier0000-0002-1097-9908
Additional Information:© ESO, 2016. Received 11 March 2016 / Accepted 29 April 2016.
Subject Keywords:instrumentation: adaptive optics / methods: data analysis / techniques: high angular resolution / techniques: interferometric
Record Number:CaltechAUTHORS:20181130-105341520
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Official Citation:Closed-loop focal plane wavefront control with the SCExAO instrument Frantz Martinache, Nemanja Jovanovic and Olivier Guyon A&A, 593 (2016) A33 DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:91366
Deposited By: George Porter
Deposited On:30 Nov 2018 19:04
Last Modified:16 Nov 2021 03:40

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