Cryogenic optical testing of an 800 mm lightweight C/SiC composite mirror mounted on a C/SiC optical bench

We tested the optical performance at cryogenic temperatures of an 800 mm diameter lightweight mirror, consisting of carbon-fiber reinforced silicon carbide and with a mass of 11.2 kg. The ceramic composite of the mirror was HB-Cesic, developed by ECM, Germany, and Mitsubishi Electric Corporation, Ja...

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Bibliographic Details
Published in:Applied optics. Optical technology and biomedical optics 2010-07, Vol.49 (20), p.3941
Main Authors: Kaneda, Hidehiro, Naitoh, Masataka, Imai, Tadashi, Tange, Yoshio, Enya, Keigo, Katayama, Haruyoshi, Maruyama, Kenta, Nakagawa, Takao, Onaka, Takashi, Suganuma, Masahiro, Kano, Ryoko, Kiriyama, Yuichi, Mori, Tatsuya, Takahashi, Ai
Format: Article
Language:English
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Summary:We tested the optical performance at cryogenic temperatures of an 800 mm diameter lightweight mirror, consisting of carbon-fiber reinforced silicon carbide and with a mass of 11.2 kg. The ceramic composite of the mirror was HB-Cesic, developed by ECM, Germany, and Mitsubishi Electric Corporation, Japan. The test was carried out while the mirror was mounted, via Invar stress relief supports, on a lightweight optical bench also made of HB-Cesic. During the test, both the mirror and the optical bench were cooled to 18 K in a liquid-helium chamber. The test consisted of measuring the mirror's change of surface figure with an interferometer installed outside the cryo-chamber. The cryogenic deformation of the mirror was 110 nm RMS with no significant residual deformation after cooling, which is very promising for the applicability of the HB-Cesic composite to large lightweight cryogenic space optics.
ISSN:2155-3165
DOI:10.1364/AO.49.003941