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Proceedings Paper

EUCLID: design of the prism DMD NIR spectrograph
Author(s): Robert Content; Ray M. Sharples; Simon Blake; R. Gordon Talbot
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Paper Abstract

EUCLID, the ESA Dark Energy Mission, contains a NIR and a visible imagers (NIP & VIS), and an NIR spectrograph (NIS). Different designs of the NIS have been studied especially a slitless design, a Digital Micromirror Device (DMD) design using grisms and another using prisms, and more recently a combination of the NIP and NIS into one instrument. We present the design of the prism DMD NIS. This design has the advantage over the slitless design of having a DMD mask which reduces the background by a factor of more than 100 and all the advantages over the grism DMD NIS that a prism gives over a grism as a higher and more uniform transmission, the absence of parasite orders, and a choice of the slope of the spectral resolution with wavelength. The field per spectrograph was made sufficiently large to reduce the number of spectrographs to two. The design was made so that the mapping of the sky of the NIS is easily compatible with the mapping strategy of the NIP and VIS. Two designs were made. In one, the field is larger but the surface shapes of the optics are complex which makes manufacturing more challenging. In the other, the design was made to be fully compatible with the manufacturing criteria of SESO after extensive discussions to carefully understand the manufacturing limitations especially the formula for highly aspheric surface shapes as biconics. This was done by directly integrating the criteria into the optimization process of ZEMAX. A calibration system that uses the DMD with the micromirrors in their OFF positions was also developed.

Paper Details

Date Published: 10 August 2010
PDF: 13 pages
Proc. SPIE 7731, Space Telescopes and Instrumentation 2010: Optical, Infrared, and Millimeter Wave, 77312Y (10 August 2010); doi: 10.1117/12.857937
Show Author Affiliations
Robert Content, Durham Univ. (United Kingdom)
Ray M. Sharples, Durham Univ. (United Kingdom)
Simon Blake, Durham Univ. (United Kingdom)
R. Gordon Talbot, Durham Univ. (United Kingdom)

Published in SPIE Proceedings Vol. 7731:
Space Telescopes and Instrumentation 2010: Optical, Infrared, and Millimeter Wave
Jacobus M. Oschmann Jr.; Mark C. Clampin; Howard A. MacEwen, Editor(s)

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