Abstract
Planned cryogenic gravitational-wave detectors will require improved coatings with a strain thermal noise reduced by a factor of 25 compared to Advanced LIGO. We present investigations of doped with as a new coating material for future detectors. Our measurements show an extinction coefficient of and a mechanical loss of at 10 K, which is a factor of 2 below that of , the currently used low refractive-index coating material. These properties make doped with ideally suited as a low-index partner material for use with -Si in the lower part of a multimaterial coating. Based on these results, we present a multimaterial coating design which, for the first time, can simultaneously meet the strict requirements on optical absorption and thermal noise of the cryogenic Einstein Telescope.
- Received 11 December 2018
DOI:https://doi.org/10.1103/PhysRevLett.122.231102
© 2019 American Physical Society
Physics Subject Headings (PhySH)
Synopsis
Mirror, Mirror—Which Coating is the Quietest of Them All
Published 13 June 2019
Gravitational-wave detectors may benefit from an alternative coating material that is less noisy at low temperatures than currently used materials.
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