Effect of elevated substrate temperature deposition on the mechanical losses in tantala thin film coatings

Vajente, G. et al. (2018) Effect of elevated substrate temperature deposition on the mechanical losses in tantala thin film coatings. Classical and Quantum Gravity, 35, 075001. (doi:10.1088/1361-6382/aaad7c)

Vajente, G. et al. (2018) Effect of elevated substrate temperature deposition on the mechanical losses in tantala thin film coatings. Classical and Quantum Gravity, 35, 075001. (doi:10.1088/1361-6382/aaad7c)

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Abstract

Brownian thermal noise in dielectric multilayer coatings limits the sensitivity of current and future interferometric gravitational wave detectors. In this work we explore the possibility of improving the mechanical losses of tantala, often used as the high refractive index material, by depositing it on a substrate held at elevated temperature. Promising results have been previously obtained with this technique when applied to amorphous silicon. We show that depositing tantala on a hot substrate reduced the mechanical losses of the as-deposited coating, but subsequent thermal treatments had a larger impact, as they reduced the losses to levels previously reported in the literature. We also show that the reduction in mechanical loss correlates with increased medium range order in the atomic structure of the coatings using x-ray diffraction and Raman spectroscopy. Finally, a discussion is included on our results, which shows that the elevated temperature deposition of pure tantala coatings does not appear to reduce mechanical loss in a similar way to that reported in the literature for amorphous silicon; and we suggest possible future research directions.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Torrie, Dr Calum and Rowan, Professor Sheila and Martin, Dr Iain and Hough, Professor James and Murray, Dr Peter
Authors: Vajente, G., Birney, R., Ananyeva, A., Angelova, S., Asselin, R., Baloukas, B., Bassiri, R., Billingsley, G., Fejer, M.M., Gibson, D., Godbout, L.J., Gustafson, E., Heptonstall, A., Hough, J., MacFoy, S., Markosyan, A., Martin, I.W., Martinu, L., Murray, P.G., Penn, S., Roorda, S., Rowan, S., Schiettekatte, F., Shink, R., Torrie, C., Vine, D., Reid, S., and Adhikari, R.X.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Classical and Quantum Gravity
Publisher:Institute of Physics
ISSN:0264-9381
ISSN (Online):1361-6382
Published Online:23 February 2018
Copyright Holders:Copyright © 2018 IOP Publishing
First Published:First published in Classical and Quantum Gravity 35:075001
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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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
624342Investigations in Gravitational Radiation / Particle Astrophysics Capital equipmentSheila RowanScience & Technology Facilities Council (STFC)ST/L003465/1S&E P&A - PHYSICS & ASTRONOMY
713721Investigations in gravitational radiationSheila RowanScience & Technology Facilities Council (STFC)ST/N005422/1S&E P&A - PHYSICS & ASTRONOMY