Dr. Jun Nishikawa Profile

Dr. Jun Nishikawa

at National Astronomical Observatory of Japan

SPIE Involvement:

Author

Publications (68)

Proceedings Article | 11 September 2024 Poster + Paper

The Grand Spherical Telescope Array (GSTA)

Jun Nishikawa

Proceedings Volume 13094, 1309435 (2024) https://doi.org/10.1117/12.3019945

KEYWORDS: Telescopes, Mirrors, Off axis mirrors, Adaptive mirrors, Adaptive optics, Optical design, Coronagraphy, Astronomical interferometers, Exoplanets, Phased arrays

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Proceedings Article | 23 August 2024 Presentation + Paper

Demonstration of coronagraphs and wavefront control at the testbed EXIST

Naoshi Murakami, Mizuki Asano, Shunya Sato, Kenta Yoneta, Jun Nishikawa

Proceedings Volume 13092, 1309220 (2024) https://doi.org/10.1117/12.3018382

KEYWORDS: Coronagraphy, Wavefronts, Spatial light modulators, Point spread functions, Exoplanets, Spiral phase plates, Wave plates, Stars

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Proceedings Article | 23 August 2024 Presentation + Paper

Experimental results of the coherent differential imaging on speckle area nulling (CDI-SAN) method

Kenta Yoneta, Jun Nishikawa, Yutaka Hayano, Masatsugu Iribe, Kodai Yamamoto, Ryo Tsukui, Naoshi Murakami, Mizuki Asano, Yosuke Tanaka, Motohide Tamura, Takahiro Sumi, Toru Yamada, Olivier Guyon, Julien Lozi, Vincent Deo, Sébastien Vievard, Kyohoon Ahn

Proceedings Volume 13092, 1309225 (2024) https://doi.org/10.1117/12.3019597

KEYWORDS: Spatial light modulators, Wavefronts, Field programmable gate arrays, Telescopes, Speckle, Exoplanets, Imaging systems, Wavefront sensors

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Proceedings Article | 23 August 2024 Presentation + Paper

The Nancy Grace Roman Space Telescope coronagraph community participation program

Dmitry Savransky, Vanessa Bailey, Schuyler Wolff, Maxwell Millar-Blanchaer, Jason Wang, Lisa Altinier, Ramya Anche, Pierre Baudoz, Beth Biller, Sarah Blunt, Wolfgang Brandner, Marah Brinjikji, Oscar Carrión-González, Amanda Chavez, Elodie Choquet, David Doelman, Julien Girard, Alexandra Greenbaum, Samantha Hasler, Justin Hom, James Ingalls, Stephen Kane, N. Jeremy Kasdin, Oliver Krause, Masayuki Kuzuhara, Alexis Lau, Zhexing Li, John Livingston, Patrick Lowrance, Kevin Ludwick, Bruce Macintosh, Eric Mamajek, Mark Marley, Johan Mazoyer, Bertrand Mennesson, Toshiyuki Mizuki, Sarah Moran, Naoshi Murakami, Jun Nishikawa, Malachi Noel, Laurent Pueyo, Sergi Hildebrandt Rafels, Jason Rhodes, Tyler Robinson, Robert De Rosa, Matthias Samland, Nicholas Schragal, Jürgen Schreiber, Jennifer Sobeck, Karl Stapelfeldt, Motohide Tamura, Taichi Uyajma, Arthur Vigan, Michele Woodland, Marie Ygouf, Kenta Yoneta, Robert Zellem, Neil Zimmerman

Proceedings Volume 13092, 130921I (2024) https://doi.org/10.1117/12.3020514

KEYWORDS: Coronagraphy, Stars, Observatories, Space telescopes, Wavefronts, Telescopes, Planets, Observational astronomy, Exoplanets

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Proceedings Article | 29 July 2024 Poster + Paper

Six-year progress of the InfraRed Doppler (IRD) instrument for the Subaru Telescope

Masayuki Kuzuhara, Takayuki Kotani, Motohide Tamura, Teruyuki Hirano, Bun'ei Sato, Masashi Omiya, Wako Aoki, Akihiko Fukui, Norio Narita, Stevanus Nugroho, Masaomi Tanaka, Hajime Kawahara, Hiroki Harakawa, Yui Kasagi, Tomoyuki Kudo, Sébastien Vievard, Takashi Kurokawa, Takuma Serizawa, Takuya Takrada, Jun Nishikawa, Akitoshi Ueda, Nobuhiko Kusakabe

Proceedings Volume 13096, 130962B (2024) https://doi.org/10.1117/12.3018629

KEYWORDS: Planets, Stars, Astronomy, Atmospheres, Exoplanets, Telescopes, Equipment, Spectroscopy, Infrared telescopes, Astrophysics

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Proceedings Article | 18 July 2024 Poster + Paper

Sixth order segmented vector vortex phase masks and shaped pupils for future telescopes

Jun Nishikawa, Naoshi Murakami, Yosuke Tanaka, Hiromi Muramatsu, Kenta Yoneta, Mizuki Asano

Proceedings Volume 13096, 130969J (2024) https://doi.org/10.1117/12.3018226

KEYWORDS: Telescopes, Manufacturing, Design, Coronagraphy, Photonic crystals, Wave plates, Stars, Exoplanets, Apodization

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Proceedings Article | 18 July 2024 Poster + Paper

The South Africa Near-Infrared Doppler (SAND) instrument: design and fabrications

Aoi Takahashi, Takayuki Kotani, Masayuki Kuzuhara, Takeru Nakajima, Riku Urago, Kou Hosokawa, Shotaro Tada, Motohide Tamura, Jun Nishikawa, Akitoshi Ueda, Takuya Takarada, Teruyuki Hirano, Takuma Kokusho, Eiko Kozaki, Takahiro Nagayama, Takahiro Sumi, Daisuke Suzuki, Hibiki Yama, Tomoyasu Yamamuro

Proceedings Volume 13096, 1309669 (2024) https://doi.org/10.1117/12.3018194

KEYWORDS: Stars, Telescopes, Spectrographs, Sand, Mirrors, Planets, Spectral resolution, Signal to noise ratio, Optical alignment, Equipment

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Proceedings Article | 18 July 2024 Poster + Paper

Assessing Earth’s atmospheric impact on near-infrared radial velocity measurements with IRD/Subaru

Yui Kasagi, Takayuki Kotani, Teruyuki Hirano, Masayuki Kuzuhara, Masashi Omiya, Takuya Takarada, Hiroki Harakawa, Tomoyuki Kudo, Jun Nishikawa, Motohide Tamura, Bun'ei Sato

Proceedings Volume 13096, 130962C (2024) https://doi.org/10.1117/12.3019372

KEYWORDS: Absorption, Stars, Transmittance, Velocity measurements, Contamination, Planets, Humidity, Earth atmosphere, Telescopes

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SPIE Journal Paper | 14 May 2024 Open Access

Laser frequency comb system for the infrared Doppler instrument on the Subaru Telescope

Takuma Serizawa, Takashi Kurokawa, Yosuke Tanaka, Jun Nishikawa, Takayuki Kotani, Motohide Tamura

JATIS, Vol. 10, Issue 02, 025006, (May 2024) https://doi.org/10.1117/12.10.1117/1.JATIS.10.2.025006

KEYWORDS: Equipment, Laser frequency, Spectroscopy, Single mode fibers, Infrared radiation, Infrared imaging, Doppler effect, Stars, Sensors, Laser systems engineering

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Proceedings Article | 5 October 2023 Presentation + Paper

Development of the coherent differential imaging on speckle area nulling (CDI-SAN) method

Kenta Yoneta, Jun Nishikawa, Yutaka Hayano, Masatsugu Iribe, Kodai Yamamoto, Ryo Tsukui, Naoshi Murakami, Mizuki Asano, Hiromu Muramatsu, Yosuke Tanaka, Motohide Tamura, Takahiro Sumi, Toru Yamada, Olivier Guyon, Julien Lozi, Vincent Deo, Sébastien Vievard, Kyohoon Ahn

Proceedings Volume 12680, 126800D (2023) https://doi.org/10.1117/12.2676294

KEYWORDS: Modulation, Coherence imaging, Speckle, Electric fields, Equipment, Wavefronts, Telescopes, Optical coherence, Exoplanets

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Proceedings Article | 29 August 2022 Poster + Presentation + Paper

Laser frequency comb system for the infrared Doppler spectrograph on the Subaru Telescope

Takuma Serizawa, Takashi Kurokawa, Yosuke Tanaka, Jun Nishikawa, Takayuki Kotani, Motohide Tamura

Proceedings Volume 12188, 121885J (2022) https://doi.org/10.1117/12.2628983

KEYWORDS: Spectroscopy, Optical fibers, Absorption, Telescopes, Infrared telescopes, Cameras, Infrared spectroscopy, Near infrared, Infrared radiation, Frequency combs

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Proceedings Article | 27 August 2022 Presentation + Paper

Recent progress of the facility for coronagraphic elemental technologies (FACET)

Kenta Yoneta, Seiji Sudoh, Hiroaki Hayashi, Mizuki Asano, Jun Nishikawa, Naoshi Murakami

Proceedings Volume 12180, 1218027 (2022) https://doi.org/10.1117/12.2628451

KEYWORDS: Coronagraphy, Spatial light modulators, Exoplanets, Wavefronts, Halftones

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SPIE Journal Paper | 11 March 2021 Open Access

Mid-infrared spectrometer and camera for the Origins Space Telescope

Itsuki Sakon, Thomas Roellig, Kimberly Ennico-Smith, Taro Matsuo, Yuji Ikeda, Tomoyasu Yamamuro, Keigo Enya, Takehiko Wada, Mitsunobu Kawada, Aoi Takahashi, Yuki Sarugaku, Naofumi Fujishiro, Naoshi Murakami, Jun Nishikawa, Takayuki Kotani, Shohei Goda, Masayuki Ido, Satoshi Itoh, Takahiro Tsuboi, Takahiro Sumi, Masatsugu Kamiura, Takeo Manome, Naoto Iida, Kentaro Yanagibashi, Thomas Greene, Bernardus Helvensteijn, Lynn Hofland, Roy Johnson, Ali Kashani, Emmett Quigley, Robert McMurray, Hanae Inami, Denis Burgarella, the Origins Space Telescope mission concept study team

JATIS, Vol. 7, Issue 01, 011013, (March 2021) https://doi.org/10.1117/12.10.1117/1.JATIS.7.1.011013

KEYWORDS: Sensors, Spectroscopy, Mirrors, Cameras, Mid-IR, Space telescopes, Electronics, Telescopes, Detector arrays, Mercury cadmium telluride

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The mid-infrared spectrometer and camera transit spectrometer (MISC-T) is one of the three baseline instruments for Origins Space Telescope (Origins) and provides the capability to assess the habitability of nearby exoplanets and search for signs of life. MISC-T employs a densified pupil optical design, and HgCdTe and Si:As detector arrays. This optical design allows the instrument to be relatively insensitive to minor line-of-sight pointing drifts and telescope aberrations, and the detectors do not require a sub-Kelvin refrigerator. MISC-T has three science spectral channels that share the same field-of-view by means of beam splitters, and all channels are operated simultaneously to cover the full spectral range from 2.8 to 20 μm at once with exquisite stability and precision (<5 ppm between 2.8 to 11 μm, <20 ppm between 11 and 20 μm). A Lyot-coronagraph-based tip–tilt sensor located in the instrument fore-optics uses the light reflected by a field stop, which corresponds to 0.3% of the light from the target, to send fine pointing information to the field steering mirror in the Origins telescope. An additional MISC Wide Field Imager (WFI) is studied as an upscope option for the Origins. MISC-WFI offers a wide field imaging (3 ′ × 3 ′ ) and low-resolution spectroscopic capability with filters and grating-prisms (grisms) covering 5 to 28 μm. The imaging capability of the MISC-WFI will be used for general science objectives. The low-resolution spectroscopic capability in MISC-WFI with a resolving power R ( = λ / Δλ) of a few hundreds will be used to measure the mid-infrared dust features and ionic lines at z up to ∼1 in the Origins mission’s Rise of Metals and Black Hole Feedback programs. The MISC-WFI also serves as a focal plane pointing and guiding instrument for the observatory, including when the MISC-T channel is performing its exoplanet spectroscopy observations.

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Proceedings Article | 28 December 2020 Poster + Presentation + Paper

The South Africa Near-Infrared Doppler (SAND) instrument: concept and instrument design

Aoi Takahashi, Takayuki Kotani, Jun Nishikawa, Akitoshi Ueda, Masayuki Kuzuhara, Motohide Tamura, Takahiro Nagayama, Mikio Kurita, Takahiro Sumi, Tomoyasu Yamamuro, Bun'ei Sato, Teruyuki Hirano, Masashi Omiya

Proceedings Volume 11447, 114473E (2020) https://doi.org/10.1117/12.2560342

KEYWORDS: Doppler effect, Stars, Planets, Telescopes, Spectroscopy, Velocity measurements, Infrared radiation, Near infrared, Infrared telescopes, Active optics

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Proceedings Article | 13 December 2020 Presentation + Paper

Construction of EXIST (Exoplanet Imaging System Testbed) toward future space coronagraphs

Naoshi Murakami, Kenta Yoneta, Hikaru Ichien, Seiji Sudoh, Keiichiro Habu, Jun Nishikawa

Proceedings Volume 11443, 114432M (2020) https://doi.org/10.1117/12.2560450

KEYWORDS: Coronagraphy, Imaging systems, Exoplanets, Spatial light modulators, Speckle, Astronomy, Stars, Optical components, Wavefronts, Control systems

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Proceedings Article | 13 December 2020 Presentation + Paper

Status of the SCExAO instrument: recent technology upgrades and path to a system-level demonstrator for PSI

Julien Lozi, Olivier Guyon, Sébastien Vievard, Ananya Sahoo, Vincent Deo, Nemanja Jovanovic, Barnaby Norris, Marc-Antoine Martinod, Ben Mazin, Alex Walter, Neelay Fruitwala, Sarah Steiger, Kristina Davis, Peter Tuthill, Tomoyuki Kudo, Hajime Kawahara, Takayuki Kotani, Michael Ireland, Theodoros Anagnos, Chrstian Schwab, Nick Cvetojevic, Elsa Huby, Sylvestre Lacour, Kevin Barjot, Tyler Groff, Jeffrey Chilcote, Jeremy Kasdin, Frantz Martinache, Romain Laugier, Mamadou N'Diaye, Justin Knight, Jared Males, Steven Bos, Frans Snik, David Doelman, Kelsey Miller, Eduardo Bendek, Ruslan Belikov, Eugene Pluzhnik, Thayne Currie, Masayuki Kuzuhara, Taichi Uyama, Jun Nishikawa, Naoshi Murakami, Jun Hashimoto, Yosuke Minowa, Christophe Clergeon, Yoshito Ono, Naruhisa Takato, Motohide Tamura, Hideki Takami, Masa Hayashi

Proceedings Volume 11448, 114480N (2020) https://doi.org/10.1117/12.2562832

KEYWORDS: Imaging systems, Telescopes, Infrared sensors, Infrared imaging, Coronagraphy, Wavefront sensors, Sensors, Detection and tracking algorithms, Cameras, Wavefronts

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Proceedings Article | 13 December 2020 Poster + Paper

Combination of apodized pupil and phase mask coronagraph for SCExAO at Subaru Telescope

Jun Nishikawa, Naoshi Murakami, Julien Lozi, Olivier Guyon, Keiichiro Habu, Hikaru Ichien, Kenta Yoneta, Seiji Sudoh, Kosuke Kumaki, Shiomi Kumagai, Nemanja Jovanovic, Frantz Martinache

Proceedings Volume 11447, 114474T (2020) https://doi.org/10.1117/12.2560839

KEYWORDS: Coronagraphy, Telescopes, Manufacturing, Infrared telescopes, Wave plates, Binary data, Etching, Adaptive optics, Visible radiation, Wavefronts

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SPIE Journal Paper | 1 October 2018

Stellar imaging coronagraph and exoplanet coronal spectrometer: two additional instruments for exoplanet exploration onboard the WSO-UV 1.7-m orbital telescope

Alexander Tavrov, Shingo Kameda, Andrey Yudaev, Ilia Dzyuban, Alexander Kiselev, Inna Shashkova, Oleg Korablev, Mikhail Sachkov, Jun Nishikawa, Motohide Tamura, Go Murakami, Keigo Enya, Masahiro Ikoma, Norio Narita

JATIS, Vol. 4, Issue 04, 044001, (October 2018) https://doi.org/10.1117/12.10.1117/1.JATIS.4.4.044001

KEYWORDS: Coronagraphy, Exoplanets, Telescopes, Ultraviolet radiation, Stars, Spectroscopy, Sensors, Planets, Spectrographs, Oxygen

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The World Space Observatory for Ultraviolet (WSO-UV) is an orbital optical telescope with a 1.7-m diameter primary mirror currently under development. The WSO-UV is aimed to operate in the 115- to 310-nm UV spectral range. Its two major science instruments are UV spectrographs and UV imaging field cameras with filter wheels. The WSO-UV project is currently in the implementation phase, with a tentative launch date in 2023. As designed, the telescope field of view in the focal plane is not fully occupied by instruments. Recently, two additional instruments devoted to exoplanets have been proposed for WSO-UV, which are the focus of this paper. UVSPEX, a UV-spectrograph for exoplanets, aims to determine atomic hydrogen and oxygen abundance in the exospheres of terrestrial exoplanets. The spectral range is 115 to 130 nm, which enables simultaneous measurement of hydrogen and oxygen emission intensities during an exoplanet transit. A study of exosphere transit photometric curves can help differentiate among different types of rocky planets. The exospheric temperature of an Earth-like planet is much higher than that of a Venus-like planet because of the low mixing ratio of the dominant coolant (CO2) in the upper atmosphere of the former, which causes a large difference in transit depth at the oxygen emission line. Thus, whether the terrestrial exoplanet is Earth-like, Venus-like, or other can be determined. A Stellar Coronagraph for Exoplanet Direct Imaging (SCEDI) is aimed to directly detect the starlight reflected from exoplanets orbiting their parent stars or from the stellar vicinity including circumstellar disks, dust, and clumps. SCEDI will create an achromatic (optimized to 420- to 700-nm wavelength range), high-contrast stellocentric coronagraphic image of a circumstellar vicinity. The two instruments, such as UVSPEX and SCEDI, share common power and control modules. The present communication outlines the science goals of both proposed instruments and explains some of their engineering features.

Proceedings Article | 24 July 2018 Presentation + Paper

The mid-infrared imager, spectrometer, coronagraph (MISC) for the Origins Space telescope (OST)

Itsuki Sakon, Thomas Roellig, Kimberly Ennico-Smith, Taro Matsuo, Yuji Ikeda, Tomoyasu Yamamuro, Naofumi Fujishiro, Keigo Enya, Aoi Takahashi, Takehiko Wada, Olivier Guyon, Takayuki Kotani, Jun Nishikawa, Naoshi Murakami, Yuki Sarugaku, Denis Burgarella

Proceedings Volume 10698, 1069817 (2018) https://doi.org/10.1117/12.2314177

KEYWORDS: Spectroscopy, Coronagraphy, Space telescopes, Imaging systems, Mid-IR, Imaging spectroscopy, Exoplanets, Sensors, Telescopes

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The Mid-infrared Imager, Spectrometer, Coronagraph (MISC) is one of the instruments studied both for the Origins Space Telescope (OST) Mission Concept 1 and 2. The MISC for OST Mission Concept 1 consists of the MISC imager and spectrometer module (MISC I and S), the MISC coronagraph module (MISC COR) and the MISC transit spectrometer module (MISC TRA). The MISC I and S offers (1) a wide field (3 arcminx3 arcmin) imaging and low-resolution spectroscopic capability with filters and grisms for 6-38 μm, (2) a medium-resolution (R~1,000) Integral Field Unit (IFU) spectroscopic capability for 5- 38 μm and (3) a high-resolution (R~25,000) slit spectroscopic capability for 12-18 μm and 25-36 μm. The MISC COR module employs PIAACMC coronagraphy method and covers 6-38 μm achieving 10-7 contrast at 0.5 arcsec from the central star. The MISC TRA module employs a densified pupil spectroscopic design to achieve 3-5 ppm of spectro-photometric stability and covers 5-26 μm with R=100-300. The MISC for OST Mission Concept 2 consists of the MISC wide field imager module (MISC WFI) and the MISC transit Spectrometer module (MISC TRA). The MISC WFI offers a wide field (3 arcmin ×3 arcmin) imaging and low-resolution spectroscopic capabilities with filters and grisms for 6-28μm. The MISC TRA module in the OST Mission Concept 2 also employs the densified pupil spectroscopic design to achieve <5 ppm of spectro-photometric stability and covers 4-22 μm with R=100-300. The highest ever spectrophotometric stability achieved by MISC TRA enables to detect bio-signatures (e.g., ozone, water, and methane) in habitable worlds in both primary and secondary transits of exoplanets and makes the OST a powerful tool to bring an revolutionary progress in exoplanet sciences. Combined with the spectroscopic capability in the FIR provided by other OST instruments, the MISC widens the wavelength coverage of OST down to 5μm, which makes the OST a powerful tool to diagnose the physical and chemical condition of the ISM using dust features, molecules lines and atomic and ionic lines. The MISC also provides the OST with a focal plane guiding function for the other OST science instruments as well as its own use.

Proceedings Article | 13 July 2018 Paper

The infrared Doppler (IRD) instrument for the Subaru telescope: instrument description and commissioning results

Takayuki Kotani, Motohide Tamura, Jun Nishikawa, Akitoshi Ueda, Masayuki Kuzuhara, Masashi Omiya, Jun Hashimoto, Masato Ishizuka, Teruyuki Hirano, Hiroshi Suto, Takashi Kurokawa, Tsukasa Kokubo, Takahiro Mori, Yosuke Tanaka, Ken Kashiwagi, Mihoko Konishi, Tomoyuki Kudo, Bun'ei Sato, Shane Jacobson, Klaus Hodapp, Donald Hall, Wako Aoki, Tomonori Usuda, Shogo Nishiyama, Tadashi Nakajima, Yuji Ikeda, Tomoyasu Yamamuro, Jun-Ichi Morino, Haruka Baba, Ko Hosokawa, Hiroyuki Ishikawa, Norio Narita, Eiichiro Kokubo, Yutaka Hayano, Hideyuki Izumiura, Eiji Kambe, Nobuhiko Kusakabe, Jungmi Kwon, Masahiro Ikoma, Yasunori Hori, Hidenori Genda, Akihiko Fukui, Yuka Fujii, Hajime Kawahara, Guyon Olivier, Nemanja Jovanovic, Hiroki Harakawa, Masahiko Hayashi, Masahide Hidai, Masahiro Machida, Taro Matsuo, Tetsuya Nagata, Masahiro Ogihara, Hideki Takami, Naruhisa Takato, Hiroshi Terada, Daehyeon Oh

Proceedings Volume 10702, 1070211 (2018) https://doi.org/10.1117/12.2311836

KEYWORDS: Stars, Spectroscopy, Telescopes, Sensors, Cameras, Error analysis, Mirrors, Infrared telescopes, Frequency combs, Adaptive optics

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Proceedings Article | 12 July 2018 Paper

Performance tests of Subaru/IRD for very precise and stable infrared radial velocity observations

Masayuki Kuzuhara, Teruyuki Hirano, Takayuki Kotani, Masato Ishizuka, Masashi Omiya, Mihoko Konishi, Tomoyuki Kudo, Jun Nishikawa, Akitoshi Ueda, Ko Hosokawa, Nobuhiko Kusakabe, Takashi Kurokawa, Tsukasa Kokubo, Takahiro Mori, Yosuke Tanaka, Shane Jacobson, Klaus Hodapp, Motohide Tamura

Proceedings Volume 10702, 1070260 (2018) https://doi.org/10.1117/12.2311832

KEYWORDS: Stars, Single mode fibers, Velocity measurements, Calibration, Polarization, Spectroscopy, Lamps, Planets

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Proceedings Article | 10 July 2018 Paper

PIAA coronagraph for Origins Space telescope (OST) mid-infrared imager, spectrometer, coronagraph (MISC) instrument

N. Fujishiro, I. Sakon, K. Enya, O. Guyon, J. Nishikawa, N. Murakami, T. Kotani, M. Tamura, A. Takahashi, T. Roellig, K. Ennico-Smith

Proceedings Volume 10706, 107065N (2018) https://doi.org/10.1117/12.2313066

KEYWORDS: Coronagraphy, Apodization, Mirrors, Geometrical optics, Space telescopes, Segmented mirrors, Mid-IR, Diffraction, Imaging systems, Spectroscopy

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Proceedings Article | 12 August 2016 Paper

Fiber mode scrambler experiments for the Subaru Infrared Doppler Instrument (IRD)

M. Ishizuka, T. Kotani, J. Nishikawa, M. Tamura, T. Kurokawa, T. Mori, T. Kokubo

Proceedings Volume 9912, 99121Q (2016) https://doi.org/10.1117/12.2232166

KEYWORDS: Planets, Doppler effect, Frequency combs, Optical fibers, Near infrared, Telescopes, Single mode fibers, Infrared radiation, Spectrographs, Precision measurement

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Proceedings Article | 1 August 2016 Paper

Contrast improvement with imperfect pre-coronagraph and dark-hole

Jun Nishikawa, Masahito Oya, Naoshi Murakami, Motohide Tamura, Takashi Kurokawa, Yosuke Tanaka, Shiomi Kumagai, Takayuki Kotani

Proceedings Volume 9904, 99043E (2016) https://doi.org/10.1117/12.2232920

KEYWORDS: Deformable mirrors, Interferometers, Nulling interferometry, Wavefronts, Adaptive optics, Stars, Exoplanets, Coronagraphy, Speckle, Photomasks

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Proceedings Article | 22 July 2016 Paper

A three-layer eight-octant phase mask towards broadband high-contrast observations

Naoshi Murakami, Jun Nishikawa, Natsumi Akaiwa, Yusuke Komuro, Naoshi Baba, Motohide Tamura

Proceedings Volume 9912, 99126G (2016) https://doi.org/10.1117/12.2231946

KEYWORDS: Exoplanets, Photonic crystals, Polarization, Coronagraphy, Light sources, Stars, Jones calculus, Space telescopes, Telescopes, Optical filters

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Proceedings Article | 22 July 2016 Paper

12.5-GHz-spaced laser frequency comb covering Y, J, and H bands for infrared Doppler instrument

T. Kokubo, T. Mori, T. Kurokawa, K. Kashiwagi, Y. Tanaka, T. Kotani, J. Nishikawa, M. Tamura

Proceedings Volume 9912, 99121R (2016) https://doi.org/10.1117/12.2232221

KEYWORDS: Spectrographs, Frequency combs, Doppler effect, Stars, Calibration, Infrared radiation, Heterodyning, Optical fibers, Optical signal processing, Spectral calibration

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SPIE Journal Paper | 24 December 2015

Extremely unbalanced interferometer for precise wavefront control in stellar coronagraphy

Inna Shashkova, Boris Shkursky, Pavel Frolov, Yulia Bezymyannikova, Alexander Kiselev, Jun Nishikawa, Alexander Tavrov

JATIS, Vol. 2, Issue 01, 011011, (December 2015) https://doi.org/10.1117/12.10.1117/1.JATIS.2.1.011011

KEYWORDS: Interferometers, Wavefronts, Coronagraphy, Adaptive optics, Beam splitters, Point spread functions, Exoplanets, Phase shift keying, Control systems, Space telescopes

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Proceedings Article | 28 August 2014 Paper

Recent progress on phase-mask coronagraphy based on photonic-crystal technology

Naoshi Murakami, Jun Nishikawa, Motohide Tamura, Eugene Serabyn, Wesley Traub, Kurt Liewer, Dwight Moody, John Trauger, Olivier Guyon, Frantz Martinache, Nemanja Jovanovic, Garima Singh, Fumika Oshiyama, Hayato Shoji, Moritsugu Sakamoto, Shoki Hamaguchi, Kazuhiko Oka, Naoshi Baba

Proceedings Volume 9143, 914334 (2014) https://doi.org/10.1117/12.2054790

KEYWORDS: Coronagraphy, Manufacturing, Photomasks, Spiral phase plates, Space telescopes, Telescopes, Light sources, Polarizers, Adaptive optics, Polarization

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Proceedings Article | 28 August 2014 Paper

Adaptive optics operation with focal wavefront sensor in a coronagraph for direct observation of exoplanets

Masahito Oya, Jun Nishikawa, Masaaki Horie, Kazuma Sato, Masao Fukase, Naoshi Murakami, Takayuki Kotani, Shiomi Kumagai, Motohide Tamura, Yosuke Tanaka, Takashi Kurokawa

Proceedings Volume 9143, 91433B (2014) https://doi.org/10.1117/12.2055670

KEYWORDS: Speckle, Coronagraphy, Wavefronts, Adaptive optics, Wavefront sensors, Sensors, Interferometers, Modulation, Astronomical imaging, Nulling interferometry

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Proceedings Article | 2 August 2014 Paper

A coronagraph system with unbalanced nulling interferometer: progress of optics and control method

Jun Nishikawa, Masahito Oya, Masaaki Horie, Kazuma Sato, Masao Fukase, Naoshi Murakami, Takayuki Kotani, Shiomi Kumagai, Motohide Tamura, Yosuke Tanaka, Takashi Kurokawa

Proceedings Volume 9143, 91433A (2014) https://doi.org/10.1117/12.2055636

KEYWORDS: Coronagraphy, Adaptive optics, Wavefronts, Interferometers, Nulling interferometry, Wavefront aberrations, Stars, Control systems, Planets, Speckle

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Proceedings Article | 14 July 2014 Paper

Infrared Doppler instrument (IRD) for the Subaru telescope to search for Earth-like planets around nearby M-dwarfs

Takayuki Kotani, Motohide Tamura, Hiroshi Suto, Jun Nishikawa, Bun'ei Sato, Wako Aoki, Tomonori Usuda, Takashi Kurokawa, Ken Kashiwagi, Shogo Nishiyama, Yuji Ikeda, Donald Hall, Klaus Hodapp, Jun Hashimoto, Jun-Ichi Morino, Yasushi Okuyama, Yosuke Tanaka, Shota Suzuki, Sadahiro Inoue, Jungmi Kwon, Takuya Suenaga, Dehyun Oh, Haruka Baba, Norio Narita, Eiichiro Kokubo, Yutaka Hayano, Hideyuki Izumiura, Eiji Kambe, Tomoyuki Kudo, Nobuhiko Kusakabe, Masahiro Ikoma, Yasunori Hori, Masashi Omiya, Hidenori Genda, Akihiko Fukui, Yuka Fujii, Olivier Guyon, Hiroki Harakawa, Masahiko Hayashi, Masahide Hidai, Teruyuki Hirano, Masayuki Kuzuhara, Masahiro Machida, Taro Matsuo, Tetsuya Nagata, Hirohi Onuki, Masahiro Ogihara, Hideki Takami, Naruhisa Takato, Yasuhiro Takahashi, Chihiro Tachinami, Hiroshi Terada, Hajime Kawahara, Tomoyasu Yamamuro

Proceedings Volume 9147, 914714 (2014) https://doi.org/10.1117/12.2055075

KEYWORDS: Stars, Optical fibers, Planets, Spectroscopy, Adaptive optics, Optical benches, Frequency combs, Sensors, Infrared telescopes, Ceramics

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Proceedings Article | 17 October 2012 Paper

Unbalanced nulling interferometer with four-quadrant phase mask

Takuji Kobayashi, Jun Nishikawa, Yosuke Tanaka, Takashi Kurokawa, Ken Kashiwagi, Naoshi Murakami, Naoshi Baba, Nobuyuki Hashimoto

Proceedings Volume 8421, 84213D (2012) https://doi.org/10.1117/12.975179

KEYWORDS: Wavefronts, Adaptive optics, Interferometers, Exoplanets, Nulling interferometry, Picture Archiving and Communication System, Coronagraphy, Stars, Planets, Phase interferometry

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Proceedings Article | 24 September 2012 Paper

Infrared Doppler instrument for the Subaru Telescope (IRD)

M. Tamura, H. Suto, J. Nishikawa, T. Kotani, B. Sato, W. Aoki, T. Usuda, T. Kurokawa, K. Kashiwagi, S. Nishiyama, Y. Ikeda, D. Hall, K. Hodapp, J. Hashimoto, J. Morino, S. Inoue, Y. Mizuno, Y. Washizaki, Y. Tanaka, S. Suzuki, J. Kwon, T. Suenaga, D. Oh, N. Narita, E. Kokubo, Y. Hayano, H. Izumiura, E. Kambe, T. Kudo, N. Kusakabe, M. Ikoma, Ya. Hori, M. Omiya, H. Genda, A. Fukui, Y. Fujii, O. Guyon, H. Harakawa, M. Hayashi, M. Hidai, T. Hirano, M. Kuzuhara, M. Machida, T. Matsuo, T. Nagata, H. Ohnuki, M. Ogihara, S. Oshino, R. Suzuki, H. Takami, N. Takato, Y. Takahashi, C. Tachinami, H. Terada

Proceedings Volume 8446, 84461T (2012) https://doi.org/10.1117/12.925885

KEYWORDS: Stars, Planets, Telescopes, Spectroscopy, Exoplanets, Adaptive optics, Space telescopes, Infrared telescopes, Near field optics, Doppler effect

Read Abstract +

Proceedings Article | 21 September 2012 Paper

Coronagraph focal-plane phase masks based on photonic crystal technology: recent progress and observational strategy

Naoshi Murakami, Jun Nishikawa, Wesley Traub, Dimitri Mawet, Dwight Moody, Brian Kern, John Trauger, Eugene Serabyn, Shoki Hamaguchi, Fumika Oshiyama, Moritsugu Sakamoto, Akitoshi Ise, Kazuhiko Oka, Naoshi Baba, Hiroshi Murakami, Motohide Tamura

Proceedings Volume 8442, 844205 (2012) https://doi.org/10.1117/12.925613

KEYWORDS: Coronagraphy, Polarization, Photonic crystals, Manufacturing, Photomasks, Stars, Polarimetry, Spiral phase plates, Phase shift keying, Planets

Read Abstract +

Proceedings Article | 21 September 2012 Paper

A coronagraph system with unbalanced nulling interferometer: progress of dynamic range

Jun Nishikawa, Kaito Yokochi, Naoshi Murakami, Lyu Abe, Takayuki Kotani, Motohide Tamura, Takashi Kurokawa, Alexander Tavrov, Mitsuo Takeda, Hiroshi Murakami

Proceedings Volume 8442, 84425D (2012) https://doi.org/10.1117/12.925792

KEYWORDS: Coronagraphy, Wavefronts, Adaptive optics, Interferometers, Wavefront aberrations, Speckle, Picture Archiving and Communication System, Nulling interferometry, Mirrors, Feedback control

Read Abstract +

Proceedings Article | 21 September 2012 Paper

SPICA coronagraph instrument: characterization of atmospheres and physical parameters of giant planets by direct imaging and spectroscopy

T. Kotani, K. Enya, T. Nakagawa, H. Matsuhara, H. Kataza, M. Kawada, M. Mita, K. Komatsu, H. Uchida, K. Fujiwara, S. Mitani, S. Sakai, K. Haze, H. Kaneda, S. Oyabu, D. Ishihara, T. Miyata, S. Sako, T. Nakamura, K. Asano, M. Tamura, J. Nishikawa, T. Yamashita, N. Narita, H. Hayano, S. Oya, E. Kokubo, Y. Itoh, T. Matsuo, M. Fukagawa, H. Shibai, M. Honda, N. Baba, N. Murakami, Y. Okamoto, S. Ida, M. Takami, L. Abe, O. Guyon, T. Yamamuro

Proceedings Volume 8442, 84420F (2012) https://doi.org/10.1117/12.925832

KEYWORDS: Coronagraphy, Imaging spectroscopy, Planets, Stars, Exoplanets, Point spread functions, Spectroscopy, Spectroscopes, Telescopes, Binary data

Read Abstract +

Proceedings Article | 21 September 2012 Paper

Adaptive optics operation with two wavefront sensors in a coronagraph for exoplanet observations

Masahito Oya, Jun Nishikawa, Masaaki Horie, Naoshi Murakami, Takayuki Kotani, Lyu Abe, Shiomi Kumagai, Motohide Tamura, Takashi Kurokawa, Hiroshi Murakami

Proceedings Volume 8442, 844255 (2012) https://doi.org/10.1117/12.925858

KEYWORDS: Coronagraphy, Adaptive optics, Wavefronts, Wavefront sensors, Sensors, Speckle, Feedback loops, Picture Archiving and Communication System, Deformable mirrors, Stars

Read Abstract +

Proceedings Article | 12 September 2012 Paper

Wavefront correction inside unbalanced nulling interferometer

Masaaki Horie, Jun Nishikawa, Masahito Oya, Naoshi Murakami, Lyu Abe, Ryo Waki, Shiomi Kumagai, Motohide Tamura, Takashi Kurokawa, Hiroshi Murakami

Proceedings Volume 8445, 84452E (2012) https://doi.org/10.1117/12.926737

KEYWORDS: Wavefronts, Adaptive optics, Interferometers, Coronagraphy, Algorithm development, Astronomical imaging, Planets, Astronomy, Nulling interferometry, Interferometry

Read Abstract +

Proceedings Article | 15 September 2011 Paper

Taking the vector vortex coronagraph to the next level for ground- and space-based exoplanet imaging instruments: review of technology developments in the USA, Japan, and Europe

Dimitri Mawet, Naoshi Murakami, Christian Delacroix, Eugene Serabyn, Olivier Absil, Naoshi Baba, Jacques Baudrand, Anthony Boccaletti, Rick Burruss, Russell Chipman, Pontus Forsberg, Serge Habraken, Shoki Hamaguchi, Charles Hanot, Akitoshi Ise, Mikael Karlsson, Brian Kern, John Krist, Andreas Kuhnert, Marie Levine, Kurt Liewer, Stephen McClain, Scott McEldowney, Bertrand Mennesson, Dwight Moody, Hiroshi Murakami, Albert Niessner, Jun Nishikawa, Nada O'Brien, Kazuhiko Oka, Peggy Park, Pierre Piron, Laurent Pueyo, Pierre Riaud, Moritsugu Sakamoto, Motohide Tamura, John Trauger, David Shemo, Jean Surdej, Nelson Tabirian, Wesley Traub, James Wallace, Kaito Yokochi

Proceedings Volume 8151, 815108 (2011) https://doi.org/10.1117/12.896059

KEYWORDS: Coronagraphy, Polarization, Spiral phase plates, Photonic crystals, Liquid crystals, Polymers, Telescopes, Exoplanets, Space telescopes, Optics manufacturing

Read Abstract +

Proceedings Article | 11 August 2010 Paper

A coronagraph system with unbalanced nulling interferometer: progress of wavefront correction

Jun Nishikawa, Kaito Yokochi, Naoshi Murakami, Lyu Abe, Takayuki Kotani, Motohide Tamura, Takashi Kurokawa, Alexander Tavrov, Mitsuo Takeda, Hiroshi Murakami

Proceedings Volume 7731, 77314O (2010) https://doi.org/10.1117/12.856945

KEYWORDS: Coronagraphy, Wavefronts, Adaptive optics, Nulling interferometry, Mirrors, Wavefront aberrations, Interferometers, Speckle, Beam splitters, Picture Archiving and Communication System

Read Abstract +

Proceedings Article | 11 August 2010 Paper

Polarization-interferometric eight-octant phase-mask coronagraph using ferroelectric liquid crystal for exoplanet detection

Naoshi Murakami, Takeshi Inabe, Toshihiko Komatsu, Jun Nishikawa, Nobuyuki Hashimoto, Makoto Kurihara, Naoshi Baba, Motohide Tamura

Proceedings Volume 7731, 77314E (2010) https://doi.org/10.1117/12.856395

KEYWORDS: Coronagraphy, Manufacturing, Polarizers, Stars, Ferroelectric LCDs, Polarization, Optics manufacturing, Exoplanets, Photomasks, Exoplanetary science

Read Abstract +

Proceedings Article | 16 July 2010 Paper

An eight-octant phase-mask coronagraph for the Subaru coronagraphic extreme AO (SCExAO) system: system design and expected performance

Naoshi Murakami, Olivier Guyon, Frantz Martinache, Taro Matsuo, Kaito Yokochi, Jun Nishikawa, Motohide Tamura, Takashi Kurokawa, Naoshi Baba, Frédéric Vogt, Vincent Garrel, Takashi Yoshikawa

Proceedings Volume 7735, 773533 (2010) https://doi.org/10.1117/12.858116

KEYWORDS: Coronagraphy, Telescopes, Polarizers, Space telescopes, Adaptive optics, Imaging systems, Apodization, Sensors, Wavefronts, Stars

Read Abstract +

Proceedings Article | 28 July 2008 Paper

Recent progress at the MIRA: development of fringe tracking system

Naoko Ohishi, Masanori Yoshizawa, Jun Nishikawa, Naoshi Murakami, Yasuo Torii, Syunsaku Suzuki, Koichi Kubo, Hikaru Iwashita, Yoshinobu Kondo

Proceedings Volume 7013, 701305 (2008) https://doi.org/10.1117/12.788985

KEYWORDS: Interferometers, Polarimetry, Mirrors, Ferroelectric materials, Sensors, Control systems, Optical tracking, Spectroscopy, Interferometry, Domes

Read Abstract +

Proceedings Article | 25 July 2008 Paper

HiCIAO: the Subaru Telescope's new high-contrast coronographic imager for adaptive optics

Klaus Hodapp, Ryuji Suzuki, Motohide Tamura, Lyu Abe, Hiroshi Suto, Ryo Kandori, Junichi Morino, Tetsuo Nishimura, Hideki Takami, Olivier Guyon, Shane Jacobson, Vern Stahlberger, Hubert Yamada, Richard Shelton, Jun Hashimoto, Alexander Tavrov, Jun Nishikawa, Nobuharu Ukita, Hideyuki Izumiura, Masahiko Hayashi, Tadashi Nakajima, Toru Yamada, Tomonori Usuda

Proceedings Volume 7014, 701419 (2008) https://doi.org/10.1117/12.788088

KEYWORDS: Adaptive optics, Telescopes, Imaging systems, Optical filters, Infrared cameras, Methane, Absorption, Sensors, Prisms, Image filtering

Read Abstract +

Proceedings Article | 12 July 2008 Paper

Virtual wavefront compensation and speckle reduction in coronagraph by unbalanced nulling interferometer (UNI) and phase and amplitude correction (PAC)

J. Nishikawa, K. Yokochi, L. Abe, N. Murakami, T. Kotani, M. Tamura, T. Kurokawa, A. V. Tavrov, M. Takeda

Proceedings Volume 7010, 70102A (2008) https://doi.org/10.1117/12.788895

KEYWORDS: Coronagraphy, Wavefronts, Adaptive optics, Picture Archiving and Communication System, Speckle, Wavefront aberrations, Interferometers, Stars, Wavefront compensation, Phase interferometry

Read Abstract +

Proceedings Article | 12 July 2008 Paper

Laboratory experiments on the 8-octant phase-mask coronagraph

Naoshi Murakami, Ryosuke Uemura, Naoshi Baba, Hiroshi Shibuya, Jun Nishikawa, Lyu Abe, Motohide Tamura, Nobuyuki Hashimoto

Proceedings Volume 7010, 70101J (2008) https://doi.org/10.1117/12.788145

KEYWORDS: Coronagraphy, Liquid crystals, Stars, Manufacturing, Numerical simulations, Polarization, Exoplanets, Helium neon lasers, Modulation, Astronomy

Read Abstract +

Proceedings Article | 12 July 2008 Paper

Mid-infrared coronagraph for SPICA

K. Enya, L. Abe, K. Haze, S. Tanaka, T. Nakagawa, H. Kataza, S. Higuchi, T. Miyata, S. Sako, T. Nakamura, M. Tamura, J. Nishikawa, N. Murakami, Y. Itoh, T. Wakayama, T. Sato, N. Nakagiri, O. Guyon, M. Venet, P. Bierden

Proceedings Volume 7010, 70102Z (2008) https://doi.org/10.1117/12.788509

KEYWORDS: Coronagraphy, Space telescopes, Infrared telescopes, Cryogenics, Telescopes, Mirrors, Binary data, Infrared radiation, Microelectromechanical systems, James Webb Space Telescope

Read Abstract +

The SPace Infrared telescope for Cosmology and Astrophysics (SPICA) is a infrared space-borne telescope mission of the next generation following AKARI. SPICA will carry a telescope with a 3.5 m diameter monolithic primary mirror and the whole telescope will be cooled to 5 K. SPICA is planned to be launched in 2017, into the sun-earth L2 libration halo orbit by an H II-A rocket and execute infrared observations at wavelengths mainly between 5 and 200 micron. The large telescope aperture, the simple pupil shape, the capability of infrared observations from space, and the early launch gives us with the SPICA mission a unique opportunity for coronagraphic observation. We have started development of a coronagraphic instrument for SPICA. The primary target of the SPICA coronagraph is direct observation of extra-solar Jovian planets. The main wavelengths of observation, the required contrast and the inner working angle (IWA) of the SPICA coronagraph are set to be 5-27 micron (3.5-5 micron is optional), 10^-6, and a few λ/D (and as small as possible), respectively, in which λ is the observation wavelength and D is the diameter of the telescope aperture (3.5m). For our laboratory demonstration, we focused first on a coronagraph with a binary shaped pupil mask as the primary candidate for SPICA because of its feasibility. In an experiment with a binary shaped pupil coronagraph with a He-Ne laser (λ=632.8nm), the achieved raw contrast was 6.7×10^-8, derived from the average measured in the dark region without active wavefront control. On the other hand, a study of Phase Induced Amplitude Apodization (PIAA) was initiated in an attempt to achieve better performance, i.e., smaller IWA and higher throughput. A laboratory experiment was performed using a He-Ne laser with active wavefront control, and a raw contrast of 6.5×10^-7 was achieved. We also present recent progress made in the cryogenic active optics for SPICA. Prototypes of cryogenic deformable by Micro Electro Mechanical Systems (MEMS) techniques were developed and a first demonstration of the deformation of their surfaces was performed with liquid nitrogen cooling. Experiments with piezo-actuators for a cryogenic tip-tilt mirror are also ongoing.

Proceedings Article | 19 September 2007 Paper

Coronagraph project with the SPICA mission

K. Enya, L. Abe, S. Tanaka, K. Haze, M. Venet, T. Nakagawa, H. Kataza, M. Tamura, J. Nishikawa, N. Murakami, K. Fujita, Y. Itoh, O. Guyon, E. Pluzhnik, T. Wakayama, T. Sato, N. Nakagiri

Proceedings Volume 6693, 66930I (2007) https://doi.org/10.1117/12.733707

KEYWORDS: Coronagraphy, Space telescopes, Telescopes, Point spread functions, Mirrors, Infrared telescopes, Binary data, James Webb Space Telescope, Photomasks, Wavefronts

Read Abstract +

We present the status of the development of a coronagraph for the Space Infrared telescope for Cosmology and Astrophysics (SPICA). SPICA is the next generation of infrared space-borne telescope missions following to AKARI, led by Japan. SPICA will carry a telescope that has a 3.5 m diameter monolithic primary mirror and the whole telescope will be cooled to 4.5 K. It is planned to launch SPICA into the sun-earth L2 libration halo orbit using H II-A rocket in the middle of the 2010s and execute infrared observations at wavelengths mainly between 5 and 200 micron. The SPICA mission gives us a unique opportunity for coronagraph observations, because of the large telescope aperture, the simple pupil shape, the capability of infrared observations from space, and the early launch. We have started development of the SPICA coronagraph in which the primary target is direct observation of extra-solar Jovian planets. The main wavelengths of observation, the required contrast and the inner working angle (IWA) of the SPICA coronagraph instrument are set to be 5-27 micron, 10^-6, and a few λ/D (and as small as possible), respectively, in which λ is the observation wavelength and D is the diameter of the telescope aperture (3.5m). We focused on a coronagraph with a binary shaped pupil mask as the primary candidate for SPICA because of its feasibility. Nano-fabrication technology using electron beam lithography was applied to manufacture a high precision mask and a laboratory experiment with a He-Ne laser (λ=632.8nm) was performed in air without active wavefront control. The raw contrast derived from the average measured in the dark region reached 6.7×10^-8. On the other hand, a study of Phase Induced Amplitude Apodization (PIAA) was started in an attempt to achieve higher performance, i.e., smaller IWA and higher throughput. A hybrid solution using PIAA and a shaped pupil mask was proposed. A laboratory experiment was performed using a He- Ne laser with active wavefront control via a 32×32 channel deformable mirror. A raw contrast of 6.5×10^-7 was achieved. Designs of binary shaped pupil mask are presented for the actual SPICA pupil which is obstructed by the telescope's secondary mirror and its support. Subtraction of point spread function (PSF) was also evaluated.

Proceedings Article | 7 July 2006 Paper

Development of an MIR coronagraph for the SPICA mission

Keigo Enya, Shinichiro Tanaka, Takao Nakagawa, Hirokazu Kataza, Lyu Abe, Motohide Tamura, Jun Nishikawa, Naoshi Murakami, Kenta Fujita, Yoich Itoh

Proceedings Volume 6265, 626536 (2006) https://doi.org/10.1117/12.670976

KEYWORDS: Coronagraphy, Space telescopes, Telescopes, Infrared telescopes, Mirrors, Point spread functions, Mid-IR, Infrared radiation, Planets, Binary data

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Proceedings Article | 28 June 2006 Paper

Concept and science of HiCIAO: high contrast instrument for the Subaru next generation adaptive optics

Motohide Tamura, Klaus Hodapp, Hideki Takami, Lyu Abe, Hiroshi Suto, Olivier Guyon, Shane Jacobson, Ryo Kandori, Jun-Ichi Morino, Naoshi Murakami, Vern Stahlberger, Ryuji Suzuki, Alexander Tavrov, Hubert Yamada, Jun Nishikawa, Nobuharu Ukita, Jun Hashimoto, Hideyuki Izumiura, Masahiko Hayashi, Tadashi Nakajima, Tetsuo Nishimura

Proceedings Volume 6269, 62690V (2006) https://doi.org/10.1117/12.670742

KEYWORDS: Coronagraphy, Adaptive optics, Stars, Telescopes, Exoplanets, Polarization, Astronomy, Optical filters, Space telescopes, Actuators

Read Abstract +

Proceedings Article | 28 June 2006 Paper

Removal of central obscuration and spiders for coronagraphy

L. Abe, J. Nishikawa, N. Murakami, M. Tamura

Proceedings Volume 6269, 626950 (2006) https://doi.org/10.1117/12.670953

KEYWORDS: Coronagraphy, Beam shaping, Telescopes, Optical filters, Adaptive optics, Apodization, Fourier transforms, Phase shifts, Astronomy, Observatories

Read Abstract +

Proceedings Article | 23 June 2006 Paper

MIRA status report: recent progress of MIRA-I.2 and future plans

Masanori Yoshizawa, Jun Nishikawa, Naoko Ohishi, Shunsaku Suzuki, Yasuo Torii, Hikaru Iwashita, Kohichi Kubo, Ko Matsuda, Naoshi Murakami, Akihisa Matsukawa, Takeshi Nishimura, Noriaki Okayasu, Sho Watanabe

Proceedings Volume 6268, 626808 (2006) https://doi.org/10.1117/12.671109

KEYWORDS: Stars, Visibility, Interferometers, Modulation, Ferroelectric materials, Mirrors, Imaging arrays, Fringe analysis, Astronomy, Observatories

Read Abstract +

Proceedings Article | 15 June 2006 Paper

Nulling and adaptive optics for very high dynamic range coronagraph

Jun Nishikawa, Naoshi Murakami, Lyu Abe, Takayuki Kotani, Motohide Tamura, Kaito Yokochi, Takashi Kurokawa

Proceedings Volume 6265, 62653Q (2006) https://doi.org/10.1117/12.671541

KEYWORDS: Coronagraphy, Wavefronts, Interferometers, Nulling interferometry, Adaptive optics, Telescopes, High dynamic range imaging, Beam splitters, Picture Archiving and Communication System, Deformable mirrors

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Proceedings Article | 20 October 2004 Paper

MIRA-I.2: recent progress

Jun Nishikawa, Masanori Yoshizawa, Naoko Ohishi, Shunsaku Suzuki, Yasuo Torii, Ko Matsuda, Koichi Kubo, Hikaru Iwashita, Takuya Yokoi, Takayuki Kotani, Koichi Sato

Proceedings Volume 5491, (2004) https://doi.org/10.1117/12.550385

KEYWORDS: Sensors, Telescopes, Mirrors, Beam splitters, Stars, Ferroelectric materials, Computing systems, Eye, Retroreflectors, CCD image sensors

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Proceedings Article | 20 October 2004 Paper

'OHANA

Guy Perrin, Olivier Lai, Julien Woillez, Jean Guerin, Takayuki Kotani, Sebastien Vergnole, Andrew Adamson, Christ Ftaclas, Olivier Guyon, Pierre Lena, Jun Nishikawa, Francois Reynaud, Katherine Roth, Stephen Ridgway, Alan Tokunaga, Peter Wizinowich

Proceedings Volume 5491, (2004) https://doi.org/10.1117/12.551585

KEYWORDS: Optical fibers, Telescopes, Interferometers, Single mode fibers, K band, Interferometry, Gemini Observatory, Space telescopes, Dispersion, Glasses

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Proceedings Article | 21 February 2003 Paper

Wavefront tilt correction system for MIRA-1.2

Naoko Ohishi, Ko Matsuda, Yasuo Torii, Jun Nishikawa, Masanori Yoshizawa, Koichi Sato, Koichi Kubo, Hikaru Iwashita, Takayuki Kotani, Toshio Fukushima

Proceedings Volume 4838, (2003) https://doi.org/10.1117/12.458086

KEYWORDS: Wavefronts, Sensors, Control systems, Mirrors, Photons, Servomechanisms, Computing systems, Visibility, Atmospheric turbulence, Interferometers

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Proceedings Article | 21 February 2003 Paper

OHANA Phase III: scientific operation of an 800-meter Mauna Kea interferometer

Olivier Lai, Stephen Ridgway, Pierre Lena, Guy Perrin, Gregory Fahlman, Andrew Adamson, Alan Tokunaga, Jun Nishikawa, Peter Wizinowich, Francois Rigaut

Proceedings Volume 4838, (2003) https://doi.org/10.1117/12.459740

KEYWORDS: Telescopes, Observatories, Interferometry, Astronomy, Data modeling, Astronomical imaging, Interferometers, Infrared telescopes, Infrared radiation, Astronomical telescopes

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Once the proof of concept of the OHANA Array has been demonstrated, the Phase II capabilities can be put into regular science operation, and the OHANA facility can be upgraded to extend interferometric operation to include all of the telescopes of the OHANA Consortium member observatories. This will constitute the Phase III of OHANA. The technical developments required will be relatively straight-forward. Longer fiber sets will be procured (fiber losses are not a limiting factor at the OHANA scale). An enhanced delay line capability will be needed in order to exploit longer baselines with good sky coverage and ample super-synthesis (several compact, multi-pass long optical delay concepts are under investigation). The scheduling and operation modes of an instrument such as OHANA present interesting opportunities and complications. We envision a place for both collaborative consortium science, based on mutual allocation of facility access, and PI-driven access, based on telescope access exchange between consortium members. The most potentially successful mode of operation would imply a community driven model, open to proposals from the different time allocation comittees. This poster looks at possible methods of allocation and operation, inspired by the UKIRT infrared survey (UKIDSS), the European VLBI, and the very interesting possibility of a Mauna Kea telescope time exchange scheme. The issue of data property is of course intimately tied with the proposal/operation system, and means of data availability and distribution are discussed, along with data interpretation tools, which may be modeled on existing systems such as the ISC at Caltech or the JMMC in France. when weighed against the UV coverage, the potential science and the uniqueness of this project, all these issues are worth an in depth study. Discussions are starting as to an OHANA Operation Committee, the goal of which would be to discuss, define and eventually carry out operational modes. The goal, of course, is for the Operation Committee to handle the details of multi-telescope scheduling in a way that will be transparent to the scientist who merely seeks the observational results.

Proceedings Article | 21 February 2003 Paper

Status report on Mitaka optical and infrared array (MIRA-1.2)

Jun Nishikawa

Proceedings Volume 4838, (2003) https://doi.org/10.1117/12.458101

KEYWORDS: Sensors, Telescopes, Stars, Mirrors, Infrared radiation, Optical arrays, Interferometers, Control systems, Computing systems, Optical alignment

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Proceedings Article | 21 February 2003 Paper

Large stellar interferometer MIRA-ST

Masanori Yoshizawa, Koichi Sato, Jun Nishikawa, Naoko Ohishi, Takayuki Kotani

Proceedings Volume 4838, (2003) https://doi.org/10.1117/12.458168

KEYWORDS: Telescopes, Interferometers, Stars, Adaptive optics, Optical fibers, Mirrors, Spatial resolution, Imaging spectroscopy, Off axis mirrors, Astronomy

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Proceedings Article | 21 February 2003 Paper

The instrumentation, object stars, and the first observations of MIRA-1.2 (Mitaka optical and infrared array)

Koichi Sato, Jun Nishikawa, Masanori Yoshizawa, Naoko Ohishi, Toshio Fukushima, Yasuo Torii, Ko Matsuda, Koichi Kubo, Hikaru Iwashita, Shunsaku Suzuki, Takayuki Kotani, Takuya Yokoi

Proceedings Volume 4838, (2003) https://doi.org/10.1117/12.458242

KEYWORDS: Stars, Interferometers, Mirrors, Sensors, Control systems, Telescopes, Spectroscopy, Infrared radiation, Optical arrays, Astronomy

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Proceedings Article | 21 February 2003 Paper

OHANA phase II: a prototype demonstrator of fiber-linked interferometry between very large telescopes

Guy Perrin, Olivier Lai, Julien Woillez, Jean Guerin, Francois Reynaud, Stephen Ridgway, Pierre Lena, Peter Wizinowich, Alan Tokunaga, Jun Nishikawa, Francois Rigaut, Andrew Adamson, Olivier Guyon

Proceedings Volume 4838, (2003) https://doi.org/10.1117/12.459382

KEYWORDS: Telescopes, Interferometers, Astronomy, Single mode fibers, Space telescopes, Prototyping, Interferometry, Astronomical imaging, Gemini Observatory, Large telescopes

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Proceedings Article | 21 February 2003 Paper

Long-baseline optical fiber interferometer instruments and science

Takayuki Kotani, Jun Nishikawa, Koichi Sato, Masanori Yoshizawa, Naoko Ohishi, Toshio Fukushima, Yasuo Torii, Ko Matsuda, Koichi Kubo, Hikaru Iwashita, Shunsaku Suzuki

Proceedings Volume 4838, (2003) https://doi.org/10.1117/12.458227

KEYWORDS: Polarization, Interferometers, Stars, Visibility, Glasses, Helium neon lasers, Telescopes, Mirrors, Polarization maintaining fibers, Interferometry

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Proceedings Article | 5 July 2000 Paper

Experiments with the fiber-connected interferometer for the MIRA project

Koichi Sato, Jun Nishikawa, Masanori Yoshizawa, Toshio Fukushima, Yasuo Torii, Ko Matsuda, Koichi Kubo, Hikaru Iwashita, Shunsaku Suzuki, David Saint-Jacques

Proceedings Volume 4006, (2000) https://doi.org/10.1117/12.390192

KEYWORDS: Laminated object manufacturing, Visibility, Fiber lasers, Interferometers, Fiber optics, Telescopes, Helium neon lasers, Glasses, Lithium, Astronomy

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Proceedings Article | 5 July 2000 Paper

Mitaka optical and infrared array first stage (MIRA-I.1) instruments

Jun Nishikawa, Koichi Sato, Masanori Yoshizawa, Toshio Fukushima, Yoshihiro Machida, Yukihiro Honma, Yasuo Torii, Ko Matsuda, Koichi Kubo, Hikaru Iwashita, Shunsaku Suzuki, Y. Kubota, K. Shimazaki, Y. Nemoto

Proceedings Volume 4006, (2000) https://doi.org/10.1117/12.390269

KEYWORDS: Sensors, Mirrors, Telescopes, Beam splitters, Avalanche photodetectors, Stars, Calibration, Infrared radiation, Optical arrays, Interferometers

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Proceedings Article | 24 July 1998 Paper

Development of the fine delay line in the Mitaka optical and infrared array (MIRA) project

Yukihiro Honma, Jun Nishikawa, Takashi Kasuga

Proceedings Volume 3350, (1998) https://doi.org/10.1117/12.317196

KEYWORDS: Eye, Prototyping, Interferometers, Infrared radiation, Optical arrays, Long baseline optical interferometry, Control systems, Optical fabrication equipment, Photography, Metals

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Proceedings Article | 24 July 1998 Paper

Development of the optical and infrared interferometer MIRA-I.2

Koichi Sato, Jun Nishikawa, Masanori Yoshizawa, Toshio Fukushima, Yoshihiro Machida, Yukihiro Honma, Ryuichiro Kuwabara, Shunsaku Suzuki, Yasuo Torii, Koichi Kubo, Ko Matsuda, Hikaru Iwashita

Proceedings Volume 3350, (1998) https://doi.org/10.1117/12.317198

KEYWORDS: Mirrors, Metrology, Fiber optics, Infrared radiation, Sensors, Interferometers, Toxic industrial chemicals, Laser systems engineering, Turbulence, Vacuum tubes

Read Abstract +

Proceedings Article | 24 July 1998 Paper

MIRA-I project: development of the Mitaka optical and infrared stellar interferometer

Yoshihiro Machida, Jun Nishikawa, Koichi Sato, Toshio Fukushima, Masanori Yoshizawa, Yukihiro Honma, Yasuo Torii, Ko Matsuda, Koichi Kubo, Masatake Ohashi, Shunsaku Suzuki, Hikaru Iwashita

Proceedings Volume 3350, (1998) https://doi.org/10.1117/12.317197

KEYWORDS: Mirrors, Sensors, Telescopes, Optical benches, Interferometers, Photons, Avalanche photodetectors, Stars, Astronomy, Observatories

Read Abstract +

Proceedings Article | 24 July 1998 Paper

MIRA-II, MIRA-III, and MIRA-SG projects: the future plan of long-baseline optical/IR interferometers in Japan

Jun Nishikawa, Koichi Sato, Toshio Fukushima, Masanori Yoshizawa, Yoshihiro Machida, Yukihiro Honma

Proceedings Volume 3350, (1998) https://doi.org/10.1117/12.317195

KEYWORDS: Telescopes, Interferometers, Long baseline optical interferometry, Infrared radiation, Optical arrays, Image resolution, Optical fibers, Imaging systems, Astronomy, Long wavelength infrared

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Showing 5 of 68 publications

Conference Committee Involvement (2)

New Frontiers in Stellar Interferometry

21 June 2004 | Glasgow, United Kingdom

Interferometry for Optical Astronomy II

22 August 2002 | Waikoloa, Hawai'i, United States

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