Thermal modelling of Advanced LIGO test masses

H. Wang, C. Blair, M. Dovale Álvarez, A. Brooks, M. F. Kasprzack, J. Ramette, P. M. Meyers, S. Kaufer, B. O'Reilly, C. M. Mow-Lowry, A. Freise

Research output: Contribution to JournalArticleAcademicpeer-review


High-reflectivity fused silica mirrors are at the epicentre of today's advanced gravitational wave detectors. In these detectors, the mirrors interact with high power laser beams. As a result of finite absorption in the high reflectivity coatings the mirrors suffer from a variety of thermal effects that impact on the detectors' performance. We propose a model of the Advanced LIGO mirrors that introduces an empirical term to account for the radiative heat transfer between the mirror and its surroundings. The mechanical mode frequency is used as a probe for the overall temperature of the mirror. The thermal transient after power build-up in the optical cavities is used to refine and test the model. The model provides a coating absorption estimate of 1.5-2.0 ppm and estimates that 0.3 to 1.3 ppm of the circulating light is scattered onto the ring heater.

Original languageEnglish
Article number115001
JournalClassical and Quantum Gravity
Issue number11
Publication statusPublished - 18 May 2017
Externally publishedYes


This work is supported by the LSC fellows program and the Science and Technology Facilities Council (STFC). 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 No. PHY-0757058.

FundersFunder number
California Institute of Technology and Massachusetts Institute of Technology
National Science FoundationPHY-0757058
Directorate for Mathematical and Physical Sciences0757058, 0823459
Science and Technology Facilities Council


    • coating absorption
    • gravitational wave detection
    • interferometry
    • mechanical mode
    • parametric instability
    • scattering loss
    • thermal modeling


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