Design of the subaru laser guide star adaptive optics module

Makoto Watanabe, Hideki Takami, Naruhisa Takato, Stephen Colley, Michael Eldred, Thomas Kane, Olivier Guyon, Masayuki Hattori, Miwa Goto, Masanori Iye, Yutaka Hayano, Yukiko Kamata, Nobuo Arimoto, Naoto Kobayashi, Yosuke Minowa

Research output: Contribution to journalConference articlepeer-review

22 Scopus citations


The laser guide star adaptive optics (AO) module for the Subaru Telescope will be installed at the f/13.9 IR Nasmyth focus, and provides the compensated image for the science instrument without change of the focal ratio. The optical components are mounted on an optical bench, and the flexure depending on the telescope pointing is eliminated. The transferred field of view for the science instrument is 2 arcmin diameter, but a 2.7 arcmin diameter field is available for tip-tilt sensing. The science path of the AO module contains five mirrors, including a pair of off-axis parabolic mirrors and a deformable mirror. It has also three additional mirrors for an image rotator. The AO module has a visible 188-element curvature based wavefront sensor (WFS) with photon-counting avalanche photodiode (APD) modules. It measures high-order terms of wavefront using either of a single laser (LGS) or natural guide star (NGS) within a 2 arcmin diameter field. The AO module has also a visible 2 × 2 sub-aperture Shack-Hartmann WFS with 16 APD modules. It measures tip-tilt and slow defocus terms of wavefront by using a single NGS within a 2.7 arcmin diameter field when a LGS is used for high-order wavefront sensing. The module has also an infrared 2 × 2 sub-aperture Shack-Hartmann WFS with a HgCdTe array as an option. Both high- and low-order visible WFSs have their own guide star acquisition units with two steering fold mirrors. The AO module has also a source simulator. It simulates LGS and NGS beams, simultaneously, with and without atmospheric turbulence by two turbulent layer at about 0 and 6 km altitudes, and reproduces the isoplanatism and the cone effect for the LGS beam.

Original languageEnglish (US)
Article number119
Pages (from-to)1096-1104
Number of pages9
JournalProceedings of SPIE - The International Society for Optical Engineering
Issue numberPART 3
StatePublished - 2004
EventAdvancements in Adaptive Optics - Glasgow, United Kingdom
Duration: Jun 21 2004Jun 25 2004


  • Adaptive optics
  • Curvature sensor
  • Laser guide star
  • Subaru telescope
  • Wavefront sensing

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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