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Comprehensive study of amorphous metal oxide and Ta₂O₅-based mixed oxide coatings for gravitational-wave detectors

Fazio, Mariana A. and Vajente, Gabriele and Yang, Le and Ananyeva, Alena and Menoni, Carmen S. (2022) Comprehensive study of amorphous metal oxide and Ta₂O₅-based mixed oxide coatings for gravitational-wave detectors. Physical Review D, 105 (10). Art. No. 102008. ISSN 2470-0010. doi:10.1103/physrevd.105.102008.

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High finesse optical cavities of current interferometric gravitational-wave detectors are significantly limited in sensitivity by laser quantum noise and coating thermal noise. The thermal noise is associated with internal energy dissipation in the materials that compose the test masses of the interferometer. Our understanding of how the internal friction is linked to the amorphous material structure is limited due to the complexity of the problem and the lack of studies that span over a large range of materials. We present a systematic investigation of amorphous metal oxide and Ta₂O₅-based mixed oxide coatings to evaluate their suitability for low Brownian noise experiments. It is shown that the mechanical loss of metal oxides is correlated to their amorphous morphology, with continuous random network materials such as SiO₂ and GeO₂ featuring the lowest loss angles. We evaluated different Ta₂O₅-based mixed oxide thin films and studied the influence of the dopant in the optical and elastic properties of the coating. We estimated the thermal noise associated with high reflectance multilayer stacks that employ each of the mixed oxides as the high index material. We concluded that the current high index material of TiO₂-doped Ta₂O₅ is the optimal choice for reduced thermal noise among Ta₂O₅-based mixed oxide coatings with low dopant concentrations.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Fazio, Mariana A.0000-0002-9057-9663
Vajente, Gabriele0000-0002-7656-6882
Yang, Le0000-0002-8868-5977
Menoni, Carmen S.0000-0001-9185-2572
Additional Information:© 2022 American Physical Society. (Received 4 August 2021; accepted 11 May 2022; published 27 May 2022) This material is based upon work supported by NSF’s LIGO Laboratory which is a major facility fully funded by the National Science Foundation. The authors gratefully acknowledge the support of the United States National Science Foundation (NSF) for the construction and operation of the LIGO Laboratory and Advanced LIGO as well as the Science and Technology Facilities Council (STFC) of the United Kingdom, and the Max-Planck-Society (MPS) for support of the construction of Advanced LIGO. Additional support for Advanced LIGO was provided by the Australian Research Council. LIGO was constructed by the California Institute of Technology and Massachusetts Institute of Technology with funding from the National Science Foundation, and operates under cooperative agreement PHY-1764464. Advanced LIGO was built under Grant No. PHY-0823459. We also acknowledge the support of the LSC Center for Coatings Research, jointly funded by the National Science Foundation (NSF) and the Gordon and Betty Moore Foundation. M. A. F. and C. S. M. acknowledge the support of the National Science Foundation under Grants No. PHY-2110101 and 2012024.
Funding AgencyGrant Number
Science and Technology Facilities Council (STFC)UNSPECIFIED
Australian Research CouncilUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
Issue or Number:10
Record Number:CaltechAUTHORS:20220601-257764000
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:114993
Deposited By: George Porter
Deposited On:01 Jun 2022 22:54
Last Modified:02 Jun 2022 14:44

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