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Correcting for the effects of pupil discontinuities with the ACAD method

Mazoyer, Johan and Pueyo, Laurent and N'Diaye, Mamadou and Mawet, Dimitri and Soummer, Rémi and Norman, Colin (2016) Correcting for the effects of pupil discontinuities with the ACAD method. In: Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave. Proceedings of SPIE. No.9904. Society of Photo-Optical Instrumentation Engineers , Bellingham, WA, Art. No. 99044T. ISBN 978-1-5106-0187-1. http://resolver.caltech.edu/CaltechAUTHORS:20161115-122345576

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Abstract

The current generation of ground-based coronagraphic instruments uses deformable mirrors to correct for phase errors and to improve contrast levels at small angular separations. Improving these techniques, several space and ground based instruments are currently developed using two deformable mirrors to correct for both phase and amplitude errors. However, as wavefront control techniques improve, more complex telescope pupil geometries (support structures, segmentation) will soon be a limiting factor for these next generation coronagraphic instruments. The technique presented in this proceeding, the Active Correction of Aperture Discontinuities method, is taking advantage of the fact that most future coronagraphic instruments will include two deformable mirrors, and is proposing to find the shapes and actuator movements to correct for the effect introduced by these complex pupil geometries. For any coronagraph previously designed for continuous apertures, this technique allow to obtain similar performance in contrast with a complex aperture (with segmented and secondary mirror support structures), with high throughput and flexibility to adapt to changing pupil geometry (e.g. in case of segment failure or maintenance of the segments). We here present the results of the parametric analysis realized on the WFIRST pupil for which we obtained high contrast levels with several deformable mirror setups (size, separation between them), coronagraphs (Vortex charge 2, vortex charge 4, APLC) and spectral bandwidths. However, because contrast levels and separation are not the only metrics to maximize the scientific return of an instrument, we also included in this study the influence of these deformable mirror shapes on the throughput of the instrument and sensitivity to pointing jitters. Finally, we present results obtained on another potential space based telescope segmented aperture. The main result of this proceeding is that we now obtain comparable performance than the coronagraphs previously designed for WFIRST. First result from the parametric analysis strongly suggest that the 2 deformable mirror set up (size and distance between them) have a important impact on the performance in contrast and throughput of the final instrument.


Item Type:Book Section
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1117/12.2232907DOIArticle
http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=2542061PublisherArticle
ORCID:
AuthorORCID
Mazoyer, Johan0000-0002-9133-3091
Mawet, Dimitri0000-0002-8895-4735
Additional Information:© 2016 SPIE. This material is based upon work carried out under subcontract #1496556 with the Jet Propulsion Laboratory funded by NASA and administered by the California Institute of Technology. We would like to thanks J. Krist (JPL) for his helpful comments on the throughput and contrast definition.
Funders:
Funding AgencyGrant Number
NASA/JPL/Caltech1496556
Subject Keywords:Instrumentation, WFIRST-AFTA, High-contrast imaging, adaptive optics, wave-front error correction, segmentation, aperture discontinuities, deformable mirror
Record Number:CaltechAUTHORS:20161115-122345576
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20161115-122345576
Official Citation:Johan Mazoyer ; Laurent Pueyo ; Mamadou N'Diaye ; Dimitri Mawet ; Rémi Soummer ; Colin Norman; Correcting for the effects of pupil discontinuities with the ACAD method. Proc. SPIE 9904, Space Telescopes and Instrumentation 2016: Optical, Infrared, and Millimeter Wave, 99044T (July 29, 2016); doi:10.1117/12.2232907
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:72034
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:15 Nov 2016 21:02
Last Modified:12 Oct 2017 14:34

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