| Project/Area Number |
09559018
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
広領域
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| Research Institution | National Astronomical Observatory |
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Principal Investigator |
SASAKI Toshiyuki Subaru Telescope, National Astronomical Observatory, Assoc. Prof., ハワイ観測所, 助教授 (80178657)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIMURA Tetuo Subaru Telescope, NAOJ Prof., ハワイ観測所, 教授 (90260017)
KAWAGUCHI Kentaro Faculty Sci., Kayama Univ. Prof., 理学部, 教授 (40158861)
IYE Masanori Optical Infrared Astr. Div., NAOJ Prof., 光学赤外線天文学研究系, 教授 (30111446)
EBIZUKA Noboru Organization for Communication, Researcher, 共同研究員
北川 清一郎 ナルックス株式会社, 研究者 代表取締役
若木 守明 東海大学, 工学部・光学工学科, 教授 (20100993)
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| Project Period (FY) |
1997 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥13,500,000 (Direct Cost: ¥13,500,000)
Fiscal Year 1999: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1998: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1997: ¥7,500,000 (Direct Cost: ¥7,500,000)
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| Keywords | grisms / telescopes / high refraction index / groove shape / 高屈折率光学材料 / 透過型回折格子 / 天体分光撮像観測装置 / レプリカ格子 / イオンエッチング / 高屈折率材料 / 回折格子形状測定 |
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| Research Abstract |
Research and development of high efficiency prisms (transmitting gratings ruled on prisms) were carried out for implementation at Faint Object Camera And Spectrograph FOCAS and for Coronagraphic Imager with Adaptive Optics CIAO both to be mounted on the 8.2m Subaru telescope.
First of all, a measuring system was set up to evaluate the ruling shape of grisms through the FFT of the intensity distribution of diffracted light. This system was then expanded to enable absolute measurement of efficiency in diffracted beams. Fabrication of grisms for CIAO, to be used in the near infrared wavelength, was tested by ruling grooves directly on infrared transmitting material made of fluorine resine using a hyper fine 3D machining system. The grism actually fabricated in this way has shown to give 65-70% diffraction efficiency in the near infrared. Low dispersion and medium dispersion grisms for FOCAS and for Trispec were made by using the standard replicating method on resin material deposited on glass base plates and was shown to give 80% diffraction efficiency.
Grisms made of high refractive index material are required for high dispersion grisms of FOCAS and for CIAO spectroscopic modes. Various methods were tested to produce deep grooves on optical material with refractive index larger than 1.9, but no promising method has yet been identified.
Germanium grisms are useful in making the size of the high dispersion spectrograph for infrared small enough to save the cost and to enhance the stability of such an instrument. It was shown in this study that such a grism actually manufactured shows acceptable performance in 10 micron wavelength application but the surface roughness is of concern for use at 2 micron wavelength.
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