Mid-infrared coronagraph for SPICA

K. Enya, L. Abe, K. Haze, S. Tanaka, T. Nakagawa, H. Kataza, S. Higuchi, T. Miyata, S. Sako, T. Nakamura, M. Tamura, J. Nishikawa, N. Murakami, Y. Itoh, T. Wakayama, T. Sato, N. Nakagiri, O. Guyon, M. Venet, P. Bierden

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Scopus citations

Abstract

The SPace Infrared telescope for Cosmology and Astrophysics (SPICA) is a infrared space-borne telescope mission of the next generation following AKARI. SPICA will carry a telescope with a 3.5 m diameter monolithic primary mirror and the whole telescope will be cooled to 5 K. SPICA is planned to be launched in 2017, into the sun-earth L2 libration halo orbit by an H II-A rocket and execute infrared observations at wavelengths mainly between 5 and 200 micron. The large telescope aperture, the simple pupil shape, the capability of infrared observations from space, and the early launch gives us with the SPICA mission a unique opportunity for coronagraphic observation. We have started development of a coronagraphic instrument for SPICA. The primary target of the SPICA coronagraph is direct observation of extra-solar Jovian planets. The main wavelengths of observation, the required contrast and the inner working angle (IWA) of the SPICA coronagraph are set to be 5-27 micron (3.5-5 micron is optional), 10-6, and a few λ/D (and as small as possible), respectively, in which λ is the observation wavelength and D is the diameter of the telescope aperture (3.5m). For our laboratory demonstration, we focused first on a coronagraph with a binary shaped pupil mask as the primary candidate for SPICA because of its feasibility. In an experiment with a binary shaped pupil coronagraph with a He-Ne laser (λ=632.8nm), the achieved raw contrast was 6.7×10-8, derived from the average measured in the dark region without active wavefront control. On the other hand, a study of Phase Induced Amplitude Apodization (PIAA) was initiated in an attempt to achieve better performance, i.e., smaller IWA and higher throughput. A laboratory experiment was performed using a He-Ne laser with active wavefront control, and a raw contrast of 6.5×10-7 was achieved. We also present recent progress made in the cryogenic active optics for SPICA. Prototypes of cryogenic deformable by Micro Electro Mechanical Systems (MEMS) techniques were developed and a first demonstration of the deformation of their surfaces was performed with liquid nitrogen cooling. Experiments with piezo-actuators for a cryogenic tip-tilt mirror are also ongoing.

Original languageEnglish (US)
Title of host publicationSpace Telescopes and Instrumentation 2008
Subtitle of host publicationOptical, Infrared, and Millimeter
DOIs
StatePublished - Dec 1 2008
Externally publishedYes
EventSpace Telescopes and Instrumentation 2008: Optical, Infrared, and Millimeter - Marseille, France
Duration: Jun 23 2008Jun 28 2008

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume7010
ISSN (Print)0277-786X

Other

OtherSpace Telescopes and Instrumentation 2008: Optical, Infrared, and Millimeter
CountryFrance
CityMarseille
Period6/23/086/28/08

Keywords

  • Coronagraph
  • Deformable mirror
  • Exo-planet
  • Infrared
  • Spica
  • Tip-tilt

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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