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

Patru, Fabien and Antichi, Jacopo and Mawet, Dimitri and Jolissaint, Laurent and Carbillet, Marcel and Milli, Julien and Girard, Julien and Rabou, Patrick and Giro, Enrico and Mourard, Denis (2014) Discretized aperture mapping with a micro-lenses array for interferometric direct imaging. In: Adaptive Optics Systems IV. Proceedings of SPIE. No.9148. Society of Photo-Optical Instrumentation Engineers (SPIE) , Bellingham, WA, Art. No. 914801.

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Discretized Aperture Mapping (DAM) appears as an original filtering technique 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 AO FOV. The corresponding image plane angular frequencies are not transmitted 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 SPIE.
Subject Keywords:adaptive optique, aliasing, spatial filtering, micro-lenses array
Series Name:Proceedings of SPIE
Issue or Number:9148
Record Number:CaltechAUTHORS:20150519-152500652
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Official Citation:Fabien Patru ; Jacopo Antichi ; Dimitri Mawet ; Laurent Jolissaint ; Marcel Carbillet, et al. " Discretized aperture mapping with a micro-lenses array for interferometric direct imaging ", Proc. SPIE 9148, Adaptive Optics Systems IV, 91485P (August 22, 2014); doi:10.1117/12.2058594;
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:57676
Deposited By: Ruth Sustaita
Deposited On:19 May 2015 23:48
Last Modified:10 Nov 2021 21:53

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