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Low Mechanical Loss TiO₂:GeO₂ Coatings for Reduced Thermal Noise in Gravitational Wave Interferometers

Vajente, Gabriele and Yang, Le and Davenport, Aaron and Fazio, Mariana and Ananyeva, Alena and Zhang, Liyuan and Billingsley, Garilynn and Prasai, Kiran and Markosyan, Ashot and Bassiri, Riccardo and Fejer, Martin M. and Chicoine, Martin and Schiettekatte, François and Menoni, Carmen S. (2021) Low Mechanical Loss TiO₂:GeO₂ Coatings for Reduced Thermal Noise in Gravitational Wave Interferometers. Physical Review Letters, 127 (7). Art. No. 071101. ISSN 0031-9007. doi:10.1103/PhysRevLett.127.071101.

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The sensitivity of current and planned gravitational wave interferometric detectors is limited, in the most critical frequency region around 100 Hz, by a combination of quantum noise and thermal noise. The latter is dominated by Brownian noise: thermal motion originating from the elastic energy dissipation in the dielectric coatings used in the interferometer mirrors. The energy dissipation is a material property characterized by the mechanical loss angle. We have identified mixtures of titanium dioxide (TiO₂) and germanium dioxide (GeO₂) that show internal dissipations at a level of 1 × 10⁻⁴, low enough to provide improvement of almost a factor of 2 on the level of Brownian noise with respect to the state-of-the-art materials. We show that by using a mixture of 44% TiO₂ and 56% GeO₂ in the high refractive index layers of the interferometer mirrors, it would be possible to achieve a thermal noise level in line with the design requirements. These results are a crucial step forward to produce the mirrors needed to meet the thermal noise requirements for the planned upgrades of the Advanced LIGO (Laser Interferometer Gravitational-Wave Observatory) and Virgo detectors.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Vajente, Gabriele0000-0002-7656-6882
Yang, Le0000-0002-8868-5977
Fazio, Mariana0000-0002-9057-9663
Zhang, Liyuan0000-0002-0898-787X
Billingsley, Garilynn0000-0002-4141-2744
Prasai, Kiran0000-0001-6552-097X
Markosyan, Ashot0000-0002-1510-3075
Bassiri, Riccardo0000-0001-8171-6833
Fejer, Martin M.0000-0002-5512-1905
Chicoine, Martin0000-0003-0630-3996
Schiettekatte, François0000-0002-2112-9378
Menoni, Carmen S.0000-0001-9185-2572
Alternate Title:Low Mechanical Loss TiO2:GeO2 Coatings for Reduced Thermal Noise in Gravitational Wave Interferometers
Additional Information:© 2021 American Physical Society. (Received 26 March 2021; revised 23 June 2021; accepted 14 July 2021; published 10 August 2021) This Letter is supported by the National Science Foundation (NSF) LIGO program through Grants No. 1710957 and No. 1708010. We also acknowledge the support of the LSC Center for Coatings Research, jointly funded by the NSF and the Gordon and Betty Moore Foundation (GBMF). K. P., A. M., R. B. and M. M. F. are grateful for support through NSF Grants No. PHY-1707866, No. PHY-1708175, No. PHY-2011571, and No. PHY-2011706, and GBMF Grant No. 6793. The work carried out at U. Montreal benefited from the support of the NSERC, the CFI, and the FRQNT through the RQMP.
Funding AgencyGrant Number
Gordon and Betty Moore Foundation6793
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Canada Foundation for InnovationUNSPECIFIED
Fonds de recherche du Québec – Nature et technologies (FRQNT)UNSPECIFIED
Issue or Number:7
Record Number:CaltechAUTHORS:20210830-203807149
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:110615
Deposited By: George Porter
Deposited On:31 Aug 2021 14:13
Last Modified:31 Aug 2021 14:13

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