Integration of high-performance compact interferometric sensors in a suspended interferometer

authored by: A. Mitchell, J. Lehmann, P. Koch, S. J. Cooper, J. van Dongen, L. Prokhorov, N. A. Holland, M. Valentini, P. Saffarieh, C. M. Mow-Lowry
Abstract: Homodyne quadrature interferometers (HoQIs) are compact, low noise and high dynamic range displacement sensors designed for use in gravitational wave observatories. Their lower noise compared to the displacement sensors used at present makes them valuable for improving the seismic isolation in current and future detectors. This paper outlines the progression of this sensor from initial production and benchtop tests to in-vacuum static performance and installation in a gravitational wave detector prototype facility. A detailed design description is outlined, including the full signal and optical chain required for implementation in detectors. The measured in-vacuum static performance indicates a noise floor of 3- 4 × 10 − 13 m Hz − 1 at 10 Hz. Three HoQIs were installed on the beamsplitter suspension at the Albert Einstein Institute 10 m gravitational wave detector prototype. They measured motion of the intermediate mass across the entire bandwidth measured and showed minimal non-linearities and a good robustness to motion in unmeasured degrees of freedom, both important for practical use in dynamic systems such as seismic isolation.
Organisation(s): Institute of Gravitation Physics
External Organisation(s): National Institute for Subatomic Physics (Nikhef)
Vrije Universiteit
Max Planck Institute for Gravitational Physics (Albert Einstein Institute)
University of Birmingham
Type: Article
Journal: Classical and quantum gravity
Volume: 42
ISSN: 0264-9381
Publication date: 30.09.2025
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Physics and Astronomy (miscellaneous)
Electronic version(s): https://doi.org/10.1088/1361-6382/ae0087 (Access: Open)

BibTeX

@article{e29c668d6def4538aecaecdb5cfa9c62,
title = "Integration of high-performance compact interferometric sensors in a suspended interferometer",
abstract = "Homodyne quadrature interferometers (HoQIs) are compact, low noise and high dynamic range displacement sensors designed for use in gravitational wave observatories. Their lower noise compared to the displacement sensors used at present makes them valuable for improving the seismic isolation in current and future detectors. This paper outlines the progression of this sensor from initial production and benchtop tests to in-vacuum static performance and installation in a gravitational wave detector prototype facility. A detailed design description is outlined, including the full signal and optical chain required for implementation in detectors. The measured in-vacuum static performance indicates a noise floor of 3- 4 × 10 − 13 m Hz − 1 at 10 Hz. Three HoQIs were installed on the beamsplitter suspension at the Albert Einstein Institute 10 m gravitational wave detector prototype. They measured motion of the intermediate mass across the entire bandwidth measured and showed minimal non-linearities and a good robustness to motion in unmeasured degrees of freedom, both important for practical use in dynamic systems such as seismic isolation.",
keywords = "Homodyne, interferometer, low-frequency, sensors, suspensions",
author = "A. Mitchell and J. Lehmann and P. Koch and Cooper, {S. J.} and {van Dongen}, J. and L. Prokhorov and Holland, {N. A.} and M. Valentini and P. Saffarieh and Mow-Lowry, {C. M.}",
note = "Publisher Copyright: {\textcopyright} 2025 The Author(s). Published by IOP Publishing Ltd.",
year = "2025",
month = sep,
day = "30",
doi = "10.1088/1361-6382/ae0087",
language = "English",
volume = "42",
journal = "Classical and quantum gravity",
issn = "0264-9381",
publisher = "IOP Publishing Ltd.",
number = "19",
}