Detectability of an orbital-angular-momentum-based gravitational wave detector
Abstract
The orbital angular momentum (OAM) of light provides a new approach to probing gravitational waves (GWs) through transitions between OAM states. Here, we assess the detectability of an OAM-based GW detector by developing a readout scheme and evaluating its noise budget over the frequency range from 1 mHz to 100 Hz, including laser-intensity noise, laser-phase noise, mode-impurity noise, and shot noise. For a symmetric superposition OAM state, the GW-induced transition amplitudes satisfy α+=−α-*, whereas the noise-induced mode-crosstalk coefficients obey n+=n-*. Hence, the GW-induced signal forms a differential-mode contribution, while laser-intensity and mode-impurity noises enter as common-mode contributions, enabling their suppression by the balanced detection. Under a fixed beam-waist constraint, a shorter arm permits a larger paraxial parameter, reducing the equivalent angular-noise strain sensitivity. We adopt an arm length of L=4 m, N=160 round trips, a paraxial parameter of γ=0.1, a laser power incident on the beam splitter of PBS=10 kW, and a wavelength of λopt=1064 nm. Using representative noise spectra, we find that, for GWs from an equal-mass binary black hole with source-frame component masses of Msrc=104 M⊙ at redshift z=1, balanced detection yields an SNR of $24.7$ for an imbalance parameter of ε=10−3 and $239$ for ε=10−5, with the sensitivity approaching the shot-noise limit in the latter case. These results highlight the importance of a compact optical configuration and strong common-mode rejection for realizing an OAM-based GW detector.
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BibTeX
@misc{wu2026detectability,
title = {{Detectability of an orbital-angular-momentum-based gravitational wave detector}},
author = {Haorong Wu and Xilong Fan},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.00085},
eprint = {2611.00085},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.00085},
}
RIS
TY - UNPB
TI - Detectability of an orbital-angular-momentum-based gravitational wave detector
AU - Haorong Wu
AU - Xilong Fan
PY - 2026
DA - 2026/11/01
PB - arXiv
DO - 10.48550/arxiv.2611.00085
UR - https://arxiv.org/abs/2611.00085
AB - The orbital angular momentum (OAM) of light provides a new approach to probing gravitational waves (GWs) through transitions between OAM states. Here, we assess the detectability of an OAM-based GW detector by developing a readout scheme and evaluating its noise budget over the frequency range from 1 mHz to 100 Hz, including laser-intensity noise, laser-phase noise, mode-impurity noise, and shot noise. For a symmetric superposition OAM state, the GW-induced transition amplitudes satisfy α_+=−α_-^*, whereas the noise-induced mode-crosstalk coefficients obey n_+=n_-^*. Hence, the GW-induced signal forms a differential-mode contribution, while laser-intensity and mode-impurity noises enter as common-mode contributions, enabling their suppression by the balanced detection. Under a fixed beam-waist constraint, a shorter arm permits a larger paraxial parameter, reducing the equivalent angular-noise strain sensitivity. We adopt an arm length of L=4 m, N=160 round trips, a paraxial parameter of γ=0.1, a laser power incident on the beam splitter of P_BS=10 kW, and a wavelength of λ_opt=1064 nm. Using representative noise spectra, we find that, for GWs from an equal-mass binary black hole with source-frame component masses of M_src=10^4 M_⊙ at redshift z=1, balanced detection yields an SNR of $24.7$ for an imbalance parameter of ε=10^−3 and $239$ for ε=10^−5, with the sensitivity approaching the shot-noise limit in the latter case. These results highlight the importance of a compact optical configuration and strong common-mode rejection for realizing an OAM-based GW detector.
ER -