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Proceedings Paper

A coronagraph system with unbalanced nulling interferometer: progress of optics and control method
Author(s): Jun Nishikawa; Masahito Oya; Masaaki Horie; Kazuma Sato; Masao Fukase; Naoshi Murakami; Takayuki Kotani; Shiomi Kumagai; Motohide Tamura; Yosuke Tanaka; Takashi Kurokawa
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Paper Abstract

We have studied a coronagraph system with an unbalanced nulling interferometer (UNI). An important characteristic is a pre-reduction of the star light to 1/100 at the UNI stage which enables to enhance the final contrast. In other point of view, the UNI stage magnifies the wavefront aberrations, which lead us to compensate for the wavefront aberrations beyond the AO systems capabilities. It consists of the UNI, adaptive optics, and a coronagraph. In our experiments, we have observed the extra speckle reduction of better than 0.07 by the advantage of the UNI system. In order to obtain better contrast, we planned to reconstruct all of the optics, which use UNI with 4QPM, a coronagraph with 8OPM or VVM, a dual feedback control method, and a wavefront correction inside the UNI by an upstream AO.

Paper Details

Date Published: 2 August 2014
PDF: 6 pages
Proc. SPIE 9143, Space Telescopes and Instrumentation 2014: Optical, Infrared, and Millimeter Wave, 91433A (2 August 2014); doi: 10.1117/12.2055636
Show Author Affiliations
Jun Nishikawa, National Astronomical Observatory of Japan (Japan)
The Graduate Univ. for Advanced Studies (Japan)
Masahito Oya, Nihon Univ. (Japan)
National Astronomical Observatory of Japan (Japan)
Masaaki Horie, Nihon Univ. (Japan)
Kazuma Sato, Tokyo Univ. of Agriculture and Technology (Japan)
National Astronomical Observatory of Japan (Japan)
Masao Fukase, Nihon Univ. (Japan)
National Astronomical Observatory of Japan (Japan)
Naoshi Murakami, Hokkaido Univ. (Japan)
Takayuki Kotani, National Astronomical Observatory of Japan (Japan)
Shiomi Kumagai, Nihon Univ. (Japan)
Motohide Tamura, The Univ. of Tokyo (Japan)
National Astronomical Observatory of Japan (Japan)
Yosuke Tanaka, Tokyo Univ. of Agriculture and Technology (Japan)
Takashi Kurokawa, Tokyo Univ. of Agriculture and Technology (Japan)
National Astronomical Observatory of Japan (Japan)


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

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