Dual balanced readout for scattered light noise mitigation in Michelson interferometers

Fuente: arXiv
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Main Authors: Lohde, André, Voigt, Daniel, Gerberding, Oliver
Format: Preprint
Published: 2024
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author Lohde, André
Voigt, Daniel
Gerberding, Oliver
author_facet Lohde, André
Voigt, Daniel
Gerberding, Oliver
contents 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. 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 \SI{13.2}{\decibel}, the readout scheme seems to be only limited by the associated noise couplings, with no theoretical limit to the scattered light suppression itself other than shot 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.
format Preprint
id arxiv_https___arxiv_org_abs_2409_04266
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Dual balanced readout for scattered light noise mitigation in Michelson interferometers
Lohde, André
Voigt, Daniel
Gerberding, Oliver
Instrumentation and Detectors
Instrumentation and Methods for Astrophysics
General Relativity and Quantum Cosmology
Optics
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. 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 \SI{13.2}{\decibel}, the readout scheme seems to be only limited by the associated noise couplings, with no theoretical limit to the scattered light suppression itself other than shot 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.
title Dual balanced readout for scattered light noise mitigation in Michelson interferometers
topic Instrumentation and Detectors
Instrumentation and Methods for Astrophysics
General Relativity and Quantum Cosmology
Optics
url https://arxiv.org/abs/2409.04266