Mirror coating solution for the cryogenic Einstein telescope

Craig, K. et al. (2019) Mirror coating solution for the cryogenic Einstein telescope. Physical Review Letters, 122(23), 231102. (doi: 10.1103/PhysRevLett.122.231102)

186572.pdf - Accepted Version



Planned, cryogenic gravitational-wave detectors will require improved coatings with a strain thermal noise reduced by a factor of 25 compared to Advanced LIGO. In this article, we present investigations of HfO2 doped with SiO2 as a new coating material for future detectors. Our measurements show an extinction coefficient of k=6×10−6 and a mechanical loss of ϕ=3.8×10−4 at 10,K, which is a factor of 2 below that of SiO2, the currently used low refractive-index coating material. These properties make HfO2 doped with SiO2 ideally suited as a low-index partner material for use with a-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.

Item Type:Articles
Additional Information:Also supported by STFC grant no. ST/L000938/1. IWM is supported by a Royal Society Research Fellowship.
Glasgow Author(s) Enlighten ID:Rowan, Professor Sheila and Bell, Dr Angus and Martin, Dr Iain and Hough, Professor James and Robie, Mr Raymond and Reid, Professor Stuart and MacLaren, Dr Ian and Penn, Professor Steven and Steinlechner, Dr Jessica and Haughian, Dr Karen and Murray, Dr Peter
Authors: Craig, K., Steinlechner, J., Murray, P. G., Bell, A. S., Birney, R., Haughian, K., Hough, J., MacLaren, I., Penn, S., Reid, S., Robie, R., Rowan, S., and Martin, I. W.
College/School:College of Science and Engineering > School of Physics and Astronomy
Research Centre:College of Science and Engineering > School of Physics and Astronomy > Institute for Gravitational Research
Journal Name:Physical Review Letters
Publisher:American Physical Society
ISSN (Online):1079-7114
Published Online:13 June 2019
Copyright Holders:Copyright © 2019 American Physical Society
First Published:First published in Physical Review Letters 122(23): 231102
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
624341Investigations in Gravitational Radiation / Particle Astrophysics Capital equipmentSheila RowanScience & Technology Facilities Council (STFC)ST/L000946/1S&E P&A - PHYSICS & ASTRONOMY
591721Optical characterisation of silicon and mirror materials for gravitational astronomy.Iain MartinThe Royal Society (ROYSOC)RG110331S&E P&A - PHYSICS & ASTRONOMY