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Discretized aperture mapping with a micro-lenses array for interferometric direct imaging

Patru, Fabien and Antichi, Jacopo and Rabou, Patrick and Giro, Enrico and Mawet, Dimitri and Milli, Julien and Girard, Julien and Carbillet, Marcel and Mourard, Denis (2013) Discretized aperture mapping with a micro-lenses array for interferometric direct imaging. In: Third AO4ELT Conference. 978-88-908876-0-4. , pp. 1-8. ISBN 978-88-908876-0-4.

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Discretized Aperture Mapping (DAM) appears as an original filtering tech nique easy to play with existing adaptive optics (AO) systems. In its essential DAM operates as an optical passive filter removing part of the phase residuals in the wavefront without introducing any difficult-to-align component in the Fourier conjugate of the entrance pupil plane. DAM reveals as a new interferometric technique combined with spatial filtering allowing direct imaging over a narrow field of view (FOV). In fact, the entrance pupil of a single telescope is divided into many sub-pupils so that the residual phase in each sub-pupil is filtered up to the DAM cut-off frequency. DAM enables to smooth the small scale wavefront defects which correspond to high spatial frequencies in the pupil plane and to low angular frequencies in the image plane. Close to the AO Nyquist frequency, such pupil plane spatial frequencies are not well measured by the wavefront sensor (WFS) due to aliasing. Once bigger than the AO Nyquist frequency, they are no more measured by the WFS due to the fitting limit responsible for the narrow AOFOV. The corresponding image plane angular frequencies are not tran smitted by DAM and are useless to image small FOVs, as stated by interferometry. That is why AO and DAM are complementary assuming that the DAM cut-off frequency is equal to the AO Nyquist frequency. Here we describe the imaging capabilities when DAM is placed downstream an AO system, over a convenient pupil which precedes the scientific detector. We show firstly that the imaging properties are preserved on a narrow FOV allowing direct imaging throughout interferometry. Then we show how the residual pupil plane spatial frequencies bigger than the AO Nyquist one are filtered out, as well as the residual halo in the image is dimmed.

Item Type:Book Section
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URLURL TypeDescription
Mawet, Dimitri0000-0002-8895-4735
Milli, Julien0000-0001-9325-2511
Girard, Julien0000-0001-8627-0404
Additional Information:© 2014
Series Name:978-88-908876-0-4
Record Number:CaltechAUTHORS:20150528-125433797
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Official Citation:Fabien Patru, Jacopo Antichi, Patrick Rabou, Enrico Giro, Dimitri Mawet, Julien Milli, Julien Girard, Marcel Carbillet, Denis Mourard Discret aperture mapping with a micro-lenses array for interferometric direct imaging In: Proceedings of the Third AO4ELT Conference. Simone Esposito and Luca Fini, eds. Firenze, Italy, 26-31 May 2013.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:57880
Deposited By: Ruth Sustaita
Deposited On:28 May 2015 21:29
Last Modified:10 Nov 2021 21:56

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