26th Australian Institute of Physics Congress and the Australian and New Zealand Conference on Optics and Photonics

Digital Interferometric Inter-Platform Sensor at the Gingin High Optical Power Facility

Not scheduled

20m

Belinda Hutchinson Building (The University of Sydney )

Poster AIP | General Relativity and Gravitation (ASGRG)

Speaker

Sheon Chua (Australian National University)

Description

Ground based gravitational-wave detectors, such as Advanced LIGO [1], Advanced Virgo [2] and KAGRA [3], use active seismic isolation to reduce optical platform motion. However, inter-platform motion presents a significant noise challenge to the low frequency sensitivity of these instruments. To achieve future sensitivity targets, suspension platform interferometry (SPI) [4] provides a potential solution via the measurement of the relative displacement and tilt between the platforms, that then allows for motion stabilization using the platform actuators.

We present the prototype multi-channel SPI sensor [5] at the Gingin the Gingin High Optical Power Facility [6], a collaboration between ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) nodes at ANU and UWA. The sensor uses Digital Interferometry [7] to multiplex and isolate the individual sensing channels. This is deployed to directly measure relative motion between seismic isolation platforms that house a longer-wavelength optical cavity [8]. We present the latest results of the SPI sensor, seismic isolation platforms and optical test cavity work.

[1] J. Aasi et al. Class. Quantum Grav. 32 074001 (2015)
[2] F. Acernese et al. Class. Quantum Grav. 32 024001 (2015)
[3] T. Akutsu et al. (KAGRA Collaboration) Prog. of Theo. and Exp. Phys., 2021(5), 05A101. Oxford Academic. (2021)
[4] S. M. Koehlenbeck et. al, Sci. Rep 13 2388 (2023)
[5] S. S. Y. Chua et. al, In preparation (2026)
[6] C. Zhao et. al, J. Phys. Conf. Ser 32 368 (2006)
[7] D. A. Shaddock, Opt. Lett. 32 (22) 3355 (2007)
[8] J. Liu et. al, In preparation (2026)