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Advanced LIGO squeezer platform for backscattered light and optical loss reduction

Fernández-Galiana, Álvaro and McCuller, Lee and Kissel, Jeff and Barsotti, Lisa and Miller, John and Tse, Maggie and Evans, Matthew and Aston, Stuart M. and Abbott, Richard and Shaffer, Thomas J. and Pele, Arnaud and Romie, Janeen H. and Weaver, Betsy and Fritschel, Peter and Mavalvala, Nergis and Matichard, Fabrice (2020) Advanced LIGO squeezer platform for backscattered light and optical loss reduction. Classical and Quantum Gravity, 37 (21). Art. No. 215015. ISSN 0264-9381. doi:10.1088/1361-6382/abb5c2.

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The Advanced LIGO gravitational-wave detectors are limited by optical quantum noise in most of their detection band. To overcome this limit, squeezed vacuum states have been injected into the Advanced LIGO detectors during the third observing run (O3), leading to an increase of their detection rate by about 40% to 50%. Here we present a key element of LIGO's squeezed vacuum source: the seismic isolation platform that houses core components placed in ultra-high vacuum. This paper describes the architecture of the isolation platform as well as the active control system, tuned to minimize backscattered light that otherwise deteriorates the sensitivity of the detectors. This architecture permits fewer optical Faraday isolators in the optical path of the squeezing system, minimizing optical losses to maximize the quantum noise improvement. The system reliably operated throughout LIGO's O3 with no evidence of noise from backscattered light. The innovative architecture of this platform makes it ideal for straightforward reshaping and adaptation to other gravitational-wave detector subsystems and low-noise optical instrumentation.

Item Type:Article
Related URLs:
URLURL TypeDescription
Fernández-Galiana, Álvaro0000-0002-8940-9261
McCuller, Lee0000-0003-0851-0593
Kissel, Jeff0000-0002-1702-9577
Barsotti, Lisa0000-0001-9819-2562
Miller, John0000-0001-8630-1610
Evans, Matthew0000-0001-8459-4499
Abbott, Richard0000-0003-1106-1178
Pele, Arnaud0000-0002-1873-3769
Fritschel, Peter0000-0003-1983-3187
Matichard, Fabrice0000-0001-8982-8418
Additional Information:© 2020 IOP Publishing Ltd. Received 3 June 2020, revised 1 September 2020, Accepted for publication 7 September 2020, Published 13 October 2020. We wish to thank Norna Robertson and Calum Torrie from LIGO-Caltech for their help in designing this system, as well as the people from the aLIGO Livingston and Hanford observatories for their help during testing and installation. 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 PHY1764464. Advanced LIGO was built under award PHY0823459. This paper is assigned the LIGO Document Number LIGO-P1800182.
Funding AgencyGrant Number
Subject Keywords:seismic isolation, advanced LIGO, squeezed vacuum, gravitational waves, active damping control
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Other Numbering System NameOther Numbering System ID
LIGO DocumentP1800182
Issue or Number:21
Record Number:CaltechAUTHORS:20201015-152733934
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Official Citation:Álvaro Fernández-Galiana et al 2020 Class. Quantum Grav. 37 215015
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:106098
Deposited By: George Porter
Deposited On:16 Oct 2020 16:18
Last Modified:26 Oct 2022 22:22

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