AO4ELT5 Proceedings

Laser guide star optimized wavefront sensor system for the Thirty Meter Telescope

Adkins, Sean (W2 Enterprises), Boyer, Corinne (Thirty Meter Telescope International Observatory), Ellerbroek, Brent (Thirty Meter Telescope International Observatory), Leach, Bob (Astronomical Research Cameras, Inc.)

As part of the adaptive optics (AO) system NFIRAOS for the Thirty Meter Telescope (TMT), TMT is developing Shack Hartmann wavefront sensor cameras optimized for laser guide star (LGS) AO. NFIRAOS will use six of these cameras in its multi-conjugate AO system for LGS AO, and one for a natural guide star pyramid wavefront sensor. Called VCAM (Visible wavelength CAMera), the wavefront sensor camera system is being developed for TMT by Astronomical Research Cameras, Inc. The LGS AO cameras use a novel CCD design called the polar coordinate detector (designated the CCID87) being developed for TMT by the Lincoln Laboratory of the Massachusetts Institute of Technology. The polar coordinate detector matches individual imagers in each subaperture to the size and orientation of the perspective elongation of the sodium laser guide star image across the 30 m telescope aperture. The detector has 128 video outputs, each of which must be read out at a 2 KHz frame rate. VCAM integrates all the electronics in a compact package and provides a 10 Gbit/s optical data link for transmission of wavefront measurements to the NFIRAOS real time computer. In this paper we describe the design of the CCID87 and VCAM and discuss the testing of the CCID87 and the VCAM prototype.

DOI: 10.26698/AO4ELT5.0115- Proceeding PDF

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