Development of immersion grating for mid-infrared high dispersion spectrograph for the 8.2m Subaru Telescope

Ebizuka, Noboru; Morita, Shinya; Shimizu, Tomoyuki; Yamagata, Yutaka; Omori, Hitoshi; Wakaki, Moriaki; Kobayashi, H.; Tokoro, Hitoshi; Hirahara, Yasuhiro

doi:10.1117/12.457402

Cited by 12 publications

(10 citation statements)

References 11 publications

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“…18 The fabrication of a Ge (n ∼ 4.0) immersion grating with the same method has been studied by a team of RIKEN, the Institute of Physical and Chemical Research, and Nagoya University. 19,20 They reported a successful fabrication of a Ge immersion grating with nearly ideal groove profiles and acceptable wavefront errors at λ ∼ 10 µm.…”

Section: Development Of Znse Immersion Gratingmentioning

confidence: 99%

WINERED: a warm near-infrared high-resolution spectrograph

Ikeda¹,

Kobayashi

Kondo

et al. 2006

SPIE Proceedings

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We are developing a new near-infrared high-resolution (R max = 100, 000) and high-sensitive spectrograph WINERED, which is specifically customized for short NIR bands at 0.9−1.35 µm. WINERED employs the following two novel approaches in the optical system: (1) portable design with a ZnSe immersion grating and (2) warm optics without any cold stops. These concepts result in several essential advantages as follows: easy to build, align, and maintain; these result in a short development time and low cost. WINERED employs a VIRGO HgCdTe 2k × 2k array by Raytheon as the detector. We are developing our own array control system that aims at a low readout noise (< 10 e − ) with a readout time of about 3 sec. Our goal is to achieve a high sensitivity of R = 100, 000 for a NIR spectroscopy of 15 mag and 17 mag point sources with 4 m and 10 m telescopes, respectively. We have just finalized the optical design and produced a proto-type electronics, which are described in the companion papers by Yasui et al. 1 and Kondo et al., 2 respectively. We plan to complete this instrument by the end of 2008 and hope to attach it to various 4 to 10 m telescopes as a PI-type instrument.

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Section: Development Of Znse Immersion Gratingmentioning

confidence: 99%

WINERED: a warm near-infrared high-resolution spectrograph

Ikeda¹,

Kobayashi

Kondo

et al. 2006

SPIE Proceedings

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“…5 Recently our group has succeeded in the fabrication of the single-crystal Germanium immersion grating by electrolytic in-process dressing (ELID) micro-machining methods. 6 This enables us to perform a high sensitivity and high wavelength resolution mid-infrared spectroscopic observation with large infrared telescopes. In the present paper, we describe the optical design and the expected performance of the "proto-type IRHS" (ProtoIRHS), which will be the first immersion grating spectrometer in the mid infrared region with R=50,000, and will be equipped to 8.2-m Subaru telescope at Mauna Kea.…”

Section: Introductionmentioning

confidence: 99%

Development of a mid-infrared high dispersion spectrograph (IRHS) for the Subaru telescope

et al. 2003

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A design of prototype Infra-Red High-dispersion Spectrograph (IRHS) is described. IRHS is a cryogenic echelle spectrometer for 8.2-m Subaru Telescope, which will operate at 8 to 13 µm with resolving power of 200,000. To achieve such a high dispersion and broad bandwidth, a Germanium immersion echelle grating was adopted. As a preliminary step, we started to develop the proto-type of IRHS (ProtoIRHS) with currently available Ge immersion grating (30×30×72 mm) and one 512×412 Si:As impurity band detector array, which will provide the maximum resolving power of 50,000 at 10 µm with slit width of 0.612 arcseconds (0.48 mm) and two-pixels sampling.

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“…It increased near the edge to 4 x 10 -5 for polarization parallel to the tangential stress component and -1.2 x 10 -4 for polarization parallel to the radial stress component. Ebizuka et al measured the homogeneity of a 32 x 32 x 80 mm germanium block for use as a grating blank 3 . No wavefront error was observed with an interferometer and an InSb camera but the sensitivity limit was not reported.…”

Section: Materials Limitationsmentioning

confidence: 99%

“…Ebizuka and his colleagues in Japan are working to construct a large germanium echelle (120 x 120 mm entrance aperture, 68.75º blaze, 600 µm groove spacing) for use in a very high resolution mid-infrared spectrometer for the SUBARU telescope 3 . They use a nanoprecision grinding technique that employs an iron bonded diamond grinding wheel.…”

Section: Introductionmentioning

confidence: 99%

Materials and fabrication issues for large machined germanium immersion gratings

et al. 2006

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LLNL has successfully fabricated small (1.5 cm 2 area) germanium immersion gratings. We studied the feasibility of producing a large germanium immersion grating by means of single point diamond flycutting. Our baseline design is a 63.4º blaze echelle with a 6 cm beam diameter. Birefringence and refractive index inhomogeneity due to stresses produced by the crystal growth process are of concern. Careful selection of the grating blank and possibly additional annealing to relieve stress will be required. The Large Optics Diamond Turning Machine (LODTM) at LLNL is a good choice for the fabrication. It can handle parts up to 1.5 meter in diameter and 0.5 meter in length and is capable of a surface figure accuracy of better than 28 nm rms. We will describe the machine modifications and the machining process for a large grating. A next generation machine, the Precision Optical Grinder and Lathe (POGAL), currently under development has tighter specifications and could produce large gratings with higher precision.

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Development of immersion grating for mid-infrared high dispersion spectrograph for the 8.2m Subaru Telescope

Cited by 12 publications

References 11 publications

WINERED: a warm near-infrared high-resolution spectrograph

WINERED: a warm near-infrared high-resolution spectrograph

Development of a mid-infrared high dispersion spectrograph (IRHS) for the Subaru telescope

Materials and fabrication issues for large machined germanium immersion gratings

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