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Proceedings Paper

Optimal apodizations for on-axis vector vortex coronagraphs
Author(s): Kevin Fogarty; Laurent Pueyo; Dimitri Mawet
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Paper Abstract

Imaging planets requires instruments capable of dealing with extreme contrast ratios and that have a high resolution. Coronagraphs that can reach a contrast ratio in a neighborhood of 109 will be capable of observing Jupiter-like planets, while those with a contrast greater than a benchmark number of 1010 to within a few λ/D of an on-axis star will render possible imaging of Earth-like planets. Plans for achieving this feat have been developed for use on telescopes with unobscured, circularly symmetric apertures. However; given that the next generation of large telescopes are on-axis designs with support structures in the telescope aperture and a central obstruction due to the secondary mirror, it has proven necessary to develop coronagraphic techniques that compensate for obstructions. Pueyo and Norman (2012) present a possible solution to the problem of the support structures using ACAD. In this paper, we present a coronagraphic design that uses a vector vortex and pupil apodization to compensate for the secondary mirror that could possibly be used in conjunction with a wavefront control system and/or ACAD. This coronagraph is capable of achieving a contrast ratio of at least 1010 in a working angle of (1:5 - 30) λ/D in conjunction with an on-axis telescope. We can construct our pupil using a classical transmissive apodizer or pupil remapping. We find that the mirror shapes required are relatively simple (requiring ≤ 40 degrees of freedom to describe) and we expect they will be feasible to manufacture, and potentially even to implement with deformable mirrors. By combining existing high-contrast imaging techniques, we demonstrate that a relatively simple design may be used to image exo-Earths.

Paper Details

Date Published: 28 August 2014
PDF: 16 pages
Proc. SPIE 9143, Space Telescopes and Instrumentation 2014: Optical, Infrared, and Millimeter Wave, 914326 (28 August 2014); doi: 10.1117/12.2056760
Show Author Affiliations
Kevin Fogarty, Johns Hopkins Univ. (United States)
Laurent Pueyo, Space Telescope Science Institute (United States)
Dimitri Mawet, European Southern Observatory (Chile)

Published in SPIE Proceedings Vol. 9143:
Space Telescopes and Instrumentation 2014: Optical, Infrared, and Millimeter Wave
Jacobus M. Oschmann Jr.; Mark Clampin; Giovanni G. Fazio; Howard A. MacEwen, Editor(s)

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