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The Infrared Imaging Spectrograph (IRIS) for TMT: optical design of IRIS imager with "Co-axis double TMA"

Tsuzuki, Toshihiro and Suzuki, Ryuji and Harakawa, Hiroki and Ikenoue, Bungo and Larkin, James and Moore, Anna and Obuchi, Yoshiyuki and Phillips, Andrew C. and Saito, Sakae and Uragachi, Fumihiro and Wincentsen, James and Wright, Shelley and Hayano, Yutaka (2016) The Infrared Imaging Spectrograph (IRIS) for TMT: optical design of IRIS imager with "Co-axis double TMA". In: Ground-based and Airborne Instrumentation for Astronomy VI. Proceedings of SPIE. No.9908. Society of Photo-Optical Instrumentation Engineers (SPIE) , Bellingham, WA, Art. No. 9908AE. ISBN 978-1-5106-0196-3. http://resolver.caltech.edu/CaltechAUTHORS:20170216-104236288

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Abstract

IRIS (InfraRed Imaging Spectrograph) is one of the first-generation instruments for the Thirty Meter Telescope (TMT). IRIS is composed of a combination of near-infrared (0.84-2.4 μm) diffraction limited imager and integral field spectrograph. To achieve near-diffraction limited resolutions in the near-infrared wavelength region, IRIS uses the advanced adaptive optics system NFIRAOS (Narrow Field Infrared Adaptive Optics System) and integrated on-instrument wavefront sensors (OIWFS). However, IRIS itself has challenging specifications. First, the overall system wavefront error should be less than 40 nm in Y, z, J, and H-band and 42 nm in K-band over a 34.0 × 34.0 arcsecond field of view. Second, the throughput of the imager components should be more than 42 percent. To achieve the extremely low wavefront error and high throughput, all reflective design has been newly proposed. We have adopted a new design policy called "Co-Axis double-TMA", which cancels the asymmetric aberrations generated by "collimator/TMA" and "camera/TMA" efficiently. The latest imager design meets all specifications, and, in particular, the wavefront error is less than 17.3 nm and throughput is more than 50.8 percent. However, to meet the specification of wavefront error and throughput as built performance, the IRIS imager requires both mirrors with low surface irregularity after high-reflection coating in cryogenic and high-level Assembly Integration and Verification (AIV). To deal with these technical challenges, we have done the tolerance analysis and found that total pass rate is almost 99 percent in the case of gauss distribution and more than 90 percent in the case of parabolic distribution using four compensators. We also have made an AIV plan and feasibility check of the optical elements. In this paper, we will present the details of this optical system.


Item Type:Book Section
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1117/12.2232491DOIArticle
http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=2543025PublisherArticle
https://arxiv.org/abs/1608.02435arXivDiscussion Paper
Additional Information:© 2016 Society of Photo-Optical Instrumentation Engineers (SPIE). The TMT Project gratefully acknowledges the support of the TMT collaborating institutions. They are the California Institute of Technology, the University of California, the National Astronomical Observatory of Japan, the National Astronomical Observatories of China and their consortium partners, the Department of Science and Technology of India and their supported institutes, and the National Research Council of Canada. This work was supported as well by the Gordon and Betty Moore Foundation, the Canada Foundation for Innovation, the Ontario Ministry of Research and Innovation, the Natural Sciences and Engineering Research Council of Canada, the British Columbia Knowledge Development Fund, the Association of Canadian Universities for Research in Astronomy (ACURA), the Association of Universities for Research in Astronomy (AURA), the U.S. National Science Foundation, the National Institutes of Natural Sciences of Japan, and the Department of Atomic Energy of India.
Group:Thirty Meter Telescope
Funders:
Funding AgencyGrant Number
Gordon and Betty Moore FoundationUNSPECIFIED
Canada Foundation for InnovationUNSPECIFIED
Ontario Ministry of Research and InnovationUNSPECIFIED
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
British Columbia Knowledge Development FundUNSPECIFIED
Association of Canadian Universities for Research in Astronomy (ACURA)UNSPECIFIED
Association of Universities for Research in Astronomy (AURA)UNSPECIFIED
NSFUNSPECIFIED
National Institutes of Natural Sciences of JapanUNSPECIFIED
Department of Atomic Energy (India)UNSPECIFIED
Subject Keywords:Infrared Imaging Spectrograph, IRIS, Thirty Meter Telescope, Optical design, Three mirror anastigmat, Adaptive Optics
Record Number:CaltechAUTHORS:20170216-104236288
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20170216-104236288
Official Citation:Toshihiro Tsuzuki ; Ryuji Suzuki ; Hiroki Harakawa ; Bungo Ikenoue ; James Larkin ; Anna Moore ; Yoshiyuki Obuchi ; Andrew C. Phillips ; Sakae Saito ; Fumihiro Uraguchi ; James Wincentsen ; Shelley Wright ; Yutaka Hayano; The Infrared Imaging Spectrograph (IRIS) for TMT: optical design of IRIS imager with "co-axis double TMA". Proc. SPIE 9908, Ground-based and Airborne Instrumentation for Astronomy VI, 9908AE (August 4, 2016); doi:10.1117/12.2232491.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:74372
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:18 Feb 2017 04:32
Last Modified:18 Feb 2017 04:32

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