Impact of Laser Guide Star Fratricide on TMT MCAO System
Abstract
Laser beams projected from the ground to form laser guide stars (LGS) experience scattering and absorption that reduce their intensity as they propagate through the atmosphere. Some fraction of the scattered light will be collected by the other LGS wavefront sensors and causes additional background in parts of the pupil. This cross-talk is referred to as the fratricide effect. In this paper we quantify the magnitude of four different sources of scattering/absorption and back scattering, and evaluate their impact on performance with various zenith angles and turbulence profiles for the Thirty Meter Telescope (TMT) MCAO system, NFIRAOS. The resulting wavefront error is on the order of 5 to 20 nm RMS, provided that the mean background from the fratricide can be calibrated and subtracted with an accuracy of 80%. We have also found that the impact of fratricide is a weak function of LGS asterism radius.
Additional Information
© 2010 SPIE. This work is supported by the Thirty Meter Telescope (TMT) project. The authors gratefully acknowledge the support of the TMT partner institutions. They are the Association of Canadian Universities for Research in Astronomy (ACURA), the California Institute of Technology and the University of California. This work was supported as well by the Gordon and Betty Moore Foundation, the Canada Foundation for Innovation, the Ontario Ministry of Research and Innovation, the National Research Council of Canada, the Natural Sciences and Engineering Research Council of Canada, the British Columbia Knowledge Development Fund, the Association of Universities for Research in Astronomy (AURA) and the U.S. National Science Foundation.Attached Files
Published - Wang2010p12876Adaptive_Optics_Systems_Pts_1-3.pdf
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Additional details
- Eprint ID
- 22920
- Resolver ID
- CaltechAUTHORS:20110316-091058117
- Association of Canadian Universities for Research in Astronomy (ACURA)
- Caltech
- University of California
- Gordon and Betty Moore Foundation
- Canada Foundation for Innovation
- Ontario Ministry of Research and Innovation
- National Research Council of Canada
- Natural Sciences and Engineering Research Council of Canada (NSERC)
- British Columbia Knowledge Development Fund
- Association of Universities for Research in Astronomy (AURA)
- NSF
- Created
-
2011-03-16Created from EPrint's datestamp field
- Updated
-
2021-11-09Created from EPrint's last_modified field
- Series Name
- Proceedings of SPIE
- Series Volume or Issue Number
- 7736