Measurement of the mechanical loss of prototype GaP/AlGaP crystalline coatings for future gravitational wave detectors

Cumming, A. et al. (2015) Measurement of the mechanical loss of prototype GaP/AlGaP crystalline coatings for future gravitational wave detectors. Classical and Quantum Gravity, 32(3), 035002. (doi: 10.1088/0264-9381/32/3/035002)

Abstract

Thermal noise associated with the dielectric optical coatings used to form the mirrors of interferometric gravitational wave detectors is expected to be an important limit to the sensitivity of future detectors. Improvements in detector performance are likely to require coating materials of lower mechanical dissipation. Typically, current coatings use multiple alternating layers of ion-beam-sputtered amorphous silica and tantalum pentoxide (doped with titania). We present here measurements of the mechanical dissipation of promising alternative crystalline coatings that use multi-layers of single crystal gallium phosphide (GaP) and aluminium gallium phosphide (AlGaP) that are epitaxially grown and lattice matched to a silicon substrate. Analysis shows that the dissipation of the crystalline coating materials appears to be significantly lower than that of the currently used amorphous coatings, potentially enabling a reduction of coating thermal noise in future gravitational wave detectors.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Cumming, Dr Alan and Rowan, Professor Sheila and Bassiri, Mr Riccardo and Martin, Dr Iain and Nawrodt, Dr Ronny and Haughian, Dr Karen and Cunningham, Dr Liam
• Authors: Cumming, A., Martin, I., Bassiri, R., Cunningham, L., Fejer, M., Harris, J., Haughian, K., Heinert, D., Lantz, B., Lin, A., Markosyan, A., Nawrodt, R., Route, R., and Rowan, S.
• 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: Classical and Quantum Gravity
• Publisher: Institute of Physics Publishing Ltd.
• ISSN: 0264-9381
• ISSN (Online): 1361-6382
• Copyright Holders: Copyright © 2015 IOP Publishing Ltd
• First Published: First published in Classical and Quantum Gravity 32(3):035002
• Publisher Policy: Reproduced under a Creative Commons License

Project Code	Award No	Project Name	Principal Investigator	Funder's Name	Funder Ref	Lead Dept
45931	3	Investigations in Gravitational Radiation.	Sheila Rowan	Science & Technologies Facilities Council (STFC)	ST/J000361/1	P&A - PHYSICS & ASTRONOMY