A Novel Arm-Length Stabilization Scheme for Gravitational-Wave Detectors with AlGaAs/GaAs Coated Mirrors
Abstract
The arm length stabilisation system is employed in gravitational-wave detectors to reduce the velocity of the mirrors such that the arm cavities can be brought onto resonance in a controlled manner required to attain the detector operating point. For future upgrades of current gravitational wave detectors such as A#, which will incorporate AlGaAs/GaAs coatings, the current frequency-doubled arm length stabilisation system is unsuitable due to excessive absorption of the frequency-doubled 532nm beam by the AlGaAs/GaAs coating. We propose a novel multi-wavelength arm length stabilisation scheme that uses both frequency-doubled and frequency-tripled beams. The 1596nm auxiliary locking beam is outside the absorption bands of AlGaAs/GaAs coating. It is frequencytripled to 532nm and phase-locked with the 1064nm science laser through its second harmonic at 532 nm. In a tabletop setup, we experimentally demonstrated the stable cavity detuning and robust cavity locking transition by controlling the 1596nm laser and 1064nm laser phase locked loop. This demonstration confirmed that the proposed novel arm length stabilisation scheme is compatible with future upgrades or third-generation gravitational wave detectors that use AlGaAs/GaAs-coated test masses.
Versions
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BibTeX
@misc{liu2026novel,
title = {{A Novel Arm-Length Stabilization Scheme for Gravitational-Wave Detectors with AlGaAs/GaAs Coated Mirrors}},
author = {Jian Liu and Juntao Pan and Carl Blair and Chiara Di Fronzo and Li Ju and Chunnong Zhao and Sheon S. Y. Chua and Bram J. J. Slagmolen and Nutsinee Kijbunchoo and David Ottaway},
howpublished = {arXiv},
year = {2026},
month = jun,
doi = {10.48550/arxiv.2606.24149},
eprint = {2606.24149},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.24149},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A Novel Arm-Length Stabilization Scheme for Gravitational-Wave Detectors with AlGaAs/GaAs Coated Mirrors
AU - Jian Liu
AU - Juntao Pan
AU - Carl Blair
AU - Chiara Di Fronzo
AU - Li Ju
AU - Chunnong Zhao
AU - Sheon S. Y. Chua
AU - Bram J. J. Slagmolen
AU - Nutsinee Kijbunchoo
AU - David Ottaway
PY - 2026
DA - 2026/06/23
PB - arXiv
DO - 10.48550/arxiv.2606.24149
UR - https://arxiv.org/abs/2606.24149
AB - The arm length stabilisation system is employed in gravitational-wave detectors to reduce the velocity of the mirrors such that the arm cavities can be brought onto resonance in a controlled manner required to attain the detector operating point. For future upgrades of current gravitational wave detectors such as A#, which will incorporate AlGaAs/GaAs coatings, the current frequency-doubled arm length stabilisation system is unsuitable due to excessive absorption of the frequency-doubled 532nm beam by the AlGaAs/GaAs coating. We propose a novel multi-wavelength arm length stabilisation scheme that uses both frequency-doubled and frequency-tripled beams. The 1596nm auxiliary locking beam is outside the absorption bands of AlGaAs/GaAs coating. It is frequencytripled to 532nm and phase-locked with the 1064nm science laser through its second harmonic at 532 nm. In a tabletop setup, we experimentally demonstrated the stable cavity detuning and robust cavity locking transition by controlling the 1596nm laser and 1064nm laser phase locked loop. This demonstration confirmed that the proposed novel arm length stabilisation scheme is compatible with future upgrades or third-generation gravitational wave detectors that use AlGaAs/GaAs-coated test masses.
ER -