Dual balanced readout for scattered light noise mitigation in Michelson interferometers

André Lohde*, Daniel Voigt*, Oliver Gerberding*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Ground-based gravitational wave detectors use laser interferometry to detect the minuscule distance change between test masses caused by gravitational waves. Stray light that scatters back into the interferometer causes transient signals that can cover the same frequency range as a potential gravitational wave signal. This scattered light noise is a potentially limiting factor in current and future detectors thus making it relevant to find new ways to mitigate it. Here, we demonstrate experimentally a technique for the subtraction of scattered light noise from the displacement readout of a Michelson interferometer. It is based on using a balanced homodyne detector at both the symmetric and the antisymmetric port. While we have been able to demonstrate a noise reduction of 13.2 dB, the readout scheme seems to be only limited by the associated noise couplings, i.e., shot noise and the coupling of laser noise. We also discuss challenges for using the dual balanced homodyne detection scheme in more complex interferometer topologies, which could lead to improvements in scattered light noise mitigation of gravitational wave detectors.

Original languageEnglish
Article number022004
Pages (from-to)1-8
Number of pages8
JournalPhysical Review D
Volume111
Issue number2
Early online date22 Jan 2025
DOIs
Publication statusPublished - 1 Feb 2025

Bibliographical note

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© 2025 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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