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Proceedings Paper • Open Access

Free-form reflective optics for mid-infrared camera and spectrometer on board SPICA

Paper Abstract

SPICA (Space Infrared Telescope for Cosmology and Astrophysics) is an astronomical mission optimized for mid-and far-infrared astronomy with a cryogenically cooled 3-m class telescope, envisioned for launch in early 2020s. Mid-infrared Camera and Spectrometer (MCS) is a focal plane instrument for SPICA with imaging and spectroscopic observing capabilities in the mid-infrared wavelength range of 5-38μm. MCS consists of two relay optical modules and following four scientific optical modules of WFC (Wide Field Camera; 5'x 5' field of view, f/11.7 and f/4.2 cameras), LRS (Low Resolution Spectrometer; 2'.5 long slits, prism dispersers, f/5.0 and f/1.7 cameras, spectral resolving power R ∼ 50-100), MRS (Mid Resolution Spectrometer; echelles, integral field units by image slicer, f/3.3 and f/1.9 cameras, R ∼ 1100-3000) and HRS (High Resolution Spectrometer; immersed echelles, f/6.0 and f/3.6 cameras, R ∼ 20000-30000). Here, we present optical design and expected optical performance of MCS. Most parts of MCS optics adopt off-axis reflective system for covering the wide wavelength range of 5-38μm without chromatic aberration and minimizing problems due to changes in shapes and refractive indices of materials from room temperature to cryogenic temperature. In order to achieve the high specification requirements of wide field of view, small F-number and large spectral resolving power with compact size, we employed the paraxial and aberration analysis of off-axial optical systems (Araki 2005 [1]) which is a design method using free-form surfaces for compact reflective optics such as head mount displays. As a result, we have successfully designed compact reflective optics for MCS with as-built performance of diffraction-limited image resolution.

Paper Details

Date Published: 20 November 2017
PDF: 10 pages
Proc. SPIE 10564, International Conference on Space Optics — ICSO 2012, 105640G (20 November 2017); doi: 10.1117/12.2309046
Show Author Affiliations
Naofumi Fujishiro, Kyoto Sangyo Univ. (Japan)
Hirokazu Kataza, Japan Aerospace Exploration Agency (Japan)
Takehiko Wada, Japan Aerospace Exploration Agency (Japan)
Yuji Ikeda, Kyoto Sangyo Univ. (Japan)
Itsuki Sakon, Univ. of Tokyo (Japan)
Shinki Oyabu, Nagoya Univ. (Japan)

Published in SPIE Proceedings Vol. 10564:
International Conference on Space Optics — ICSO 2012
Bruno Cugny; Errico Armandillo; Nikos Karafolas, Editor(s)

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