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The four-quadrant phase-mask coronagraph: white light laboratory results with an achromatic device

Mawet, D. and Riaud, P. and Baudrand, J. and Baudoz, P. and Boccaletti, A. and Dupuis, O. and Rouan, D. (2006) The four-quadrant phase-mask coronagraph: white light laboratory results with an achromatic device. Astronomy and Astrophysics, 448 (2). pp. 801-808. ISSN 0004-6361. doi:10.1051/0004-6361:20054158.

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Achromatic coronagraphs are the subject of intensive research since they will be mandatory for many programs which aim at detecting and characterizing exoplanets. We report a laboratory experiment assessing the performance of the Four-Quadrant Phase-Mask coronagraph (FQPM) over a broadband wavelength range (R≈2). The achromatization of the FQPM is provided by achromatic halfwave plates (HWP). These phase shifters combine birefringent plates made of different materials with properly chosen thicknesses. The HWP thickness control is relaxed by two orders of magnitudes with respect to the classical (non-birefringent) dispersive plate approach. In our experiment we used a two stage stack of Quartz and MgF_2. This combination allows to cover a large spectral range in the visible (500-900nm) with a small phase error residual around π(≈0.12 rad rms). With this achromatization, we obtained an attenuation of 755 on the white light PSF peak. This solution is directly applicable to ground-based telescopes using high order adaptive optics such as the ESO's VLT-Planet Finder project and could easily be transposed in the mid-infrared domain for future space-based missions like DARWIN/TPF.

Item Type:Article
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URLURL TypeDescription
Mawet, D.0000-0002-8895-4735
Boccaletti, A.0000-0001-9353-2724
Additional Information:© 2006 ESO. Article published by EDP Sciences. Received 6 September 2005; Accepted 8 November 2005. D.M. acknowledges the financial support of the Belgian “Fonds pour la formation à la Recherche dans l’Industrie et dans l’Agriculture”. P.R. acknowledges the financial support of the “Pôle d’Attraction Inter-Universitaire”. We also are very grateful to the financial support of the “BQR” contract from the Paris-Meudon Observatory. We warmly acknowledge Olivier Absil and the anonymous referee for useful comments.
Funding AgencyGrant Number
Fonds pour la Formation à la Recherche dans l’índustrie et dans l’Ágriculture (FRIA)UNSPECIFIED
Pôle d’Attraction Inter-UniversitaireUNSPECIFIED
Paris-Meudon ObservatoryUNSPECIFIED
Subject Keywords:instrumentation: adaptive optics -- techniques: high angular resolution -- stars: planetary systems -- methods: observational
Issue or Number:2
Record Number:CaltechAUTHORS:20150520-105118860
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Official Citation:D. Mawet, P. Riaud, J. Baudrand, P. Baudoz, A. Boccaletti, O. Dupuis and D. Rouan A&A 448 (2) 801-808 (2006) DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:57706
Deposited By: Tony Diaz
Deposited On:20 May 2015 18:14
Last Modified:10 Nov 2021 21:54

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