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 Sudo, Kosuke Kumaki, Shiomi Kumagaih, Nemanja Jovanovic, Frantz Martinache

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


Subaru telescope has been operating a high-contrast imaging instruments called Subaru coronagraphic extreme adaptive optics (SCExAO) which is used for exoplanet research. We are developing phase mask coronagraphs using photonic crystal wave plates inside the SCExAO. An eight-octant phase mask (8OPM) of three-layer achromatic structure has been fabricated as a second generation. It was designed for J and H band to reach 10-5 contrast, and Ks band to 10-4. A retardation and a coronagraphic performance of the 8OPM were confirmed almost as designed at 1550nm. An apodised (binary shaped) pupil to be used with the 8OPM was also studied to suppress diffracted light by the secondary shadow and spiders. We confirmed a performance of the combination of the apodizer and the 8OPM at visible wavelengths in a lab. We optimized the apodizer for a pupil of the SCExAO where we obtained a transmission of 50 % and a contrast of 10-4 at the center and 10-6 at outer region. We manufactured the designed apodizer to be installed in SCExAO for infrared observations.

Original languageEnglish (US)
Title of host publicationGround-Based and Airborne Instrumentation for Astronomy VIII
EditorsChristopher J. Evans, Julia J. Bryant, Kentaro Motohara
ISBN (Electronic)9781510636811
StatePublished - 2020
EventGround-Based and Airborne Instrumentation for Astronomy VIII 2020 - Virtual, Online, United States
Duration: Dec 14 2020Dec 22 2020

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering


ConferenceGround-Based and Airborne Instrumentation for Astronomy VIII 2020
Country/TerritoryUnited States
CityVirtual, Online


  • Adaptive optics
  • Apodizer
  • Coronagraph
  • Exoplanet
  • Phase mask
  • Shaped pupil

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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