The CHARIS IFS for high contrast imaging at Subaru

Tyler D. Groff, N. Jeremy Kasdin, Mary Anne Limbach, Michael Galvin, Michael A. Carr, Gillian Knapp, Timothy Brandt, Craig Loomis, Norman Jarosik, Kyle Mede, Michael W. McElwain, Douglas B. Leviton, Kevin H. Miller, Manuel A. Quijada, Olivier Guyon, Nemanja Jovanovic, Naruhisa Takato, Masahiko Hayashi

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

37 Scopus citations


The Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS) is an integral field spectrograph (IFS) being built for the Subaru telescope. CHARIS will take spectra of brown dwarfs and hot Jovian planets in the coronagraphic image provided by the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) and AO188 adaptive optics systems.1, 2 The system is designed to detect objects five orders of magnitude dimmer than their parent star down to an 80 milliarcsecond inner working angle. For characterization, CHARIS has a high-resolution prism providing an average spectral resolution of R82, R69, and R82 in J, H, and K bands respectively. The so-called discovery mode uses a second low-resolution prism with an average spectral resolution of R19 spanning 1.15-2.37 microns (J+H+K bands). This is unique compared to other high contrast IFS designs. It augments low inner working angle performance by reducing the separation at which we can rely on spectral differential imaging. The principal challenge for a high-contrast IFS is quasi-static speckles, which cause undue levels of spectral crosstalk. CHARIS has addressed this through several key design aspects that should constrain crosstalk between adjacent spectral features to be below 1%. Sitting on the Nasmyth platform, the alignment between the lenslet array, prism, and detector will be highly stable, key for the performance of the data pipeline. Nearly every component has arrived and the project is entering its final build phase. Here we review the science case, the resulting design, status of final construction, and lessons learned that are directly applicable to future exoplanet instruments.

Original languageEnglish (US)
Title of host publicationTechniques and Instrumentation for Detection of Exoplanets VII
EditorsStuart Shaklan
ISBN (Electronic)9781628417715
StatePublished - 2015
EventTechniques and Instrumentation for Detection of Exoplanets VII - San Diego, United States
Duration: Aug 10 2015Aug 13 2015

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherTechniques and Instrumentation for Detection of Exoplanets VII
Country/TerritoryUnited States
CitySan Diego

All Science Journal Classification (ASJC) codes

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


  • Coronagraphy
  • Exoplanets
  • Extreme Adaptive Optics
  • Integral Field Spectrograph
  • Lenslet


Dive into the research topics of 'The CHARIS IFS for high contrast imaging at Subaru'. Together they form a unique fingerprint.

Cite this