6 July 2006 Novel immersion grating, VPH grating, and quasi-Bragg grating
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We have successfully fabricated germanium immersion gratings with resolving power of 45,000 at 10 μm by using a nano precision 3D grinding machine and ELID (ELectrolytic In-process Dressing) method. However the method spends large amount of machine times. We propose grooves shape with a new principle for a solid grating, which achieves high performance and lower cost. We have developed volume phase holographic (VPH) grisms with zinc selenide (ZnSe) prisms for spectrograph of the Subaru Telescope and the other telescopes. While a VPH grism with high index prisms achieves higher dispersion, diffraction efficiency of VPH grating decreases toward higher orders. A "quasi-Bragg grating" which inherits advantage of a VPH grating achieves high diffraction efficiency toward higher orders. Wavelength tuners with a pair of counter-rotation prisms for a VPH and quasi-Bragg grating obtain high diffraction efficiency over wide wavelength range. The novel immersion grating, VPH grism with high index prisms, quasi-Bragg grating and wavelength tuners dramatically reduce volumes of astronomical spectrographs.
© (2006) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Noboru Ebizuka, Keiko Oka, Akiko Yamada, Masako Kashiwagi, Kashiko Kodate, Koji S. Kawabata, Mariko Uehara, Chie Nagashima, Kotaro Ichiyama, Takashi Ichikawa, Tomoyuki Shimizu, Shinya Morita, Yutaka Yamagata, Hitoshi Omori, Hitoshi Tokoro, Yasuhiro Hirahara, Shuji Sato, Masanori Iye, "Novel immersion grating, VPH grating, and quasi-Bragg grating", Proc. SPIE 6273, Optomechanical Technologies for Astronomy, 62732G (6 July 2006); doi: 10.1117/12.671100; https://doi.org/10.1117/12.671100


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