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The VORTEX project: first results and perspectives

Absil, Olivier and Mawet, Dimitri and Delacroix, Christian and Forsberg, Pontus and Karlsson, Mikael and Habraken, Serge and Surdej, Jean and Absil, Pierre-Antoine and Carlomagno, Brunella and Christiaens, Valentin and Defrère, Denis and Gomez Gonzales, Carlos and Huby, Elsa and Jolivet, Aїssa and Milli, Julien and Piron, Pierre and Vargas Catalan, Ernesto and Van Droogenbroeck, Marc (2014) The VORTEX project: first results and perspectives. In: Adaptive Optics Systems IV. Proceedings of SPIE. No.9148. Society of Photo-Optical Instrumentation Engineers (SPIE) , Bellingham, WA, Art. No. 91480M. https://resolver.caltech.edu/CaltechAUTHORS:20150521-114932586

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Abstract

Vortex coronagraphs are among the most promising solutions to perform high contrast imaging at small angular separations from bright stars. They feature a very small inner working angle (down to the diffraction limit of the telescope), a clear 360 degree discovery space, have demonstrated very high contrast capabilities, are easy to implement on high-contrast imaging instruments, and have already been extensively tested on the sky. Since 2005, we have been designing, developing and testing an implementation of the charge-2 vector vortex phase mask based on concentric sub-wavelength gratings, referred to as the Annular Groove Phase Mask (AGPM). Science-grade mid-infrared AGPMs were produced in 2012 for the first time, using plasma etching on synthetic diamond substrates. They have been validated on a coronagraphic test bench, showing broadband peak rejection up to 500:1 in the L band, which translates into a raw contrast of about 6 x 10^(-5) at 2⋋=D. Three of them have now been installed on world-leading diffraction-limited infrared cameras, namely VLT/NACO, VLT/VISIR and LBT/LMIRCam. During the science verification observations with our L-band AGPM on NACO, we observed the beta Pictoris system and obtained unprecedented sensitivity limits to planetary companions down to the diffraction limit (0.1"). More recently, we obtained new images of the HR 8799 system at L band during the AGPM first light on LMIRCam. After reviewing these first results obtained with mid-infrared AGPMs, we will discuss the short- and mid-term goals of the on-going VORTEX project, which aims to improve the performance of our vortex phase masks for future applications on second-generation high-contrast imager and on future extremely large telescopes (ELTs). In particular, we will briefly describe our current efforts to improve the manufacturing of mid-infrared AGPMs, to push their operation to shorter wavelengths, and to provide deeper starlight extinction by creating new designs for higher topological charge vortices. Within the VORTEX project, we also plan to develop new image processing techniques tailored to coronagraphic images, and to study some pre- and post-coronagraphic concepts adapted to the vortex coronagraph in order to reduce scattered starlight in the final images.


Item Type:Book Section
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1117/12.2055702DOIArticle
http://arxiv.org/abs/1410.5635arXivDiscussion Paper
ORCID:
AuthorORCID
Absil, Olivier0000-0002-4006-6237
Mawet, Dimitri0000-0002-8895-4735
Karlsson, Mikael0000-0002-2011-0851
Surdej, Jean0000-0002-7005-1976
Absil, Pierre-Antoine0000-0003-2946-4178
Christiaens, Valentin0000-0002-0101-8814
Defrère, Denis0000-0003-3499-2506
Gomez Gonzales, Carlos0000-0003-2050-1710
Milli, Julien0000-0001-9325-2511
Additional Information:© 2014 Society of Photo-Optical Instrumentation Engineers (SPIE). Date Published: 21 July 2014. The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (ERC Grant Agreement n.337569) and from the French Community of Belgium through an ARC grant for Concerted Research Actions. O.A. is a Research Associate of the F.R.S.-FNRS (Belgium). The early successes of this project wouldn't have been possible without the contributions of many collaborators outside the co-authors of this paper (aka the \VORTEX team"). We would like to thank particularly P. Riaud and J. Baudrand for their decisive contributions to the genesis of this project, A. Boccaletti and P. Baudoz for maintaining and sharing with us their coronagraphic test bench at Observatoire de Paris-Meudon, E. Pantin and the CEA team for inviting and helping us to piggyback on the VISIR upgrade, J. Girard and the excellent ESO staff for making possible the installation of the AGPM on NACO, P. Hinz and A. Skemer for installing one of our L-band AGPMs on LMIRCam, B. Mennesson and K. Wallace for manufacturing optimized Lyot stops for the AGPM on LMIRCam, R. Olivier for designing and manufacturing the opto-mechanical interfaces for the AGPM, D. Vandormael for printing centering cross hairs on some of our AGPMs, J.-F. Fagnard for cryo-testing the AGPMs, and finally C. Hanot for his many contributions to this endeavor.
Funders:
Funding AgencyGrant Number
European Research Council (ERC)337569
Communauté française de Belgique – Actions de recherche concertéesUNSPECIFIED
Subject Keywords:Exoplanets, high contrast imaging, coronagraphy, vortex phase mask
Series Name:Proceedings of SPIE
Issue or Number:9148
Record Number:CaltechAUTHORS:20150521-114932586
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20150521-114932586
Official Citation:Olivier Absil ; Dimitri Mawet ; Christian Delacroix ; Pontus Forsberg ; Mikael Karlsson, et al. " The VORTEX project: first results and perspectives ", Proc. SPIE 9148, Adaptive Optics Systems IV, 91480M (July 21, 2014); doi:10.1117/12.2055702; http://dx.doi.org/10.1117/12.2055702
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:57739
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:21 May 2015 19:55
Last Modified:11 Oct 2019 01:31

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