Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Optical Sensors and Sensing Congress

Quantum-limited absorption estimation with ring resonators

Alexandre Belsley, Euan J. Allen, Animesh Datta, Jonathan C. F. Matthews

Published Jan 1, 2022• 0 citations
Publisher

Abstract

Coherent-state probes in appropriately designed all-pass ring resonators outperform any quantum probe single-pass absorption estimation strategy, including those using Fock or bright squeezed states.
DOI
10.1364/sensors.2022.stu4g.1

Related papers

Coherent States in Ring Resonators Outperform Any Quantum Probe Single-pass Absorption Estimation Strategy

Alexandre Belsley, Euan J. Allen, Animesh Datta +1 more

By leveraging interference and resonance enhancement effects, we find all-pass ring resonators with coherent-state probes can estimate absorption more precisely than any quantum probe single-pass strategy, including those using squeezed or Fock states.

Quantum 2.0 Conference and Exhibition•Jan 1, 2022•0 citations

Advantage of Coherent States in Ring Resonators over Any Quantum Probe Single-Pass Absorption Estimation Strategy

Alexandre Belsley, Euan J. Allen, Animesh Datta +1 more

Quantum states of light have been shown to enhance precision in absorption estimation over classical strategies. By exploiting interference and resonant enhancement effects, we show that coherent-state probes in all-pass ring resonators can outperform any quantum probe single-pass strategy even when normalized by the mean input photon number. We also find that under optimal conditions coherent-state probes equal the performance of arbitrarily bright pure single-mode squeezed probes in all-pass ring resonators.

arXiv:2112.07557•Physical Review Letters•Jun 6, 2022•21 citations

Quantum-enhanced metrology with the single-mode coherent states of an optical cavity inside a quantum feedback loop

AM Clark, A Stokes, A Beige

•Aug 23, 2016•0 citations

Quantum-limited Loss and Phase Estimation Using All-pass Ring Resonators

Alexandre Belsley, Euan J. Allen, Animesh Datta +1 more

We derive the fundamental quantum limits in estimating the absorption coefficient and refractive index of an analyte using all-pass ring resonators. We find coherent-states are optimal probes and can outperform any quantum probe single-pass strategy.

Frontiers in Optics•Jan 1, 2022•0 citations

Full-optical realization of tunable low pass, high pass and band pass optical filters using ring resonators

Ali Rostami, Golriz Rostami

Optics Communications•Jul 7, 2004•14 citations

Optimal quantum metrology of two-photon absorption

Athena Karsa, Ranjith Nair, A. Chia +2 more

Abstract Two-photon absorption (TPA) is a nonlinear optical process with wide-ranging applications from spectroscopy to super-resolution imaging. Despite this, the precise measurement and characterisation of TPA parameters are challenging due to their inherently weak nature. We study the potential of single-mode quantum light to enhance TPA parameter estimation through the quantum Fisher information (QFI). Discrete variable quantum states (defined to be a finite superposition of Fock states) are optimised to maximise the QFI for given absorption, revealing a quantum advantage compared to both the coherent state (classical) benchmark and the single-mode squeezed vacuum state. For fixed average energy n ¯ ∈ 2 N , the Fock state is shown to be optimal for large TPA parameters, while a superposition of vacuum and a particular Fock state is optimal for small absorption for all n ¯ . This differs from single-photon absorption where the Fock state is always optimal. Notably, photon counting is demonstrated to offer optimal or nearly optimal performance compared to the QFI bound for all levels of TPA parameters for the optimised quantum probes, and their quantum advantage is shown to be robust to single-photon loss. Our findings provide insight into known limiting behaviours of Gaussian probes and their different FI scalings under photon counting ( ∝ n ¯ 2 for squeezed vacuum states versus n ¯ 3 for coherent states). The squeezed state outperforms coherent states for small TPA parameters but underperforms in the intermediate regime, becoming comparable in the large absorption limit. This can be explained through fundamental differences between behaviours of even and odd number Fock states: the former’s QFI diverges in both large and small absorption limits, while the latter diverges only in the small absorption limit, dominating at intermediate scales.

Quantum Science and Technology•May 2, 2024•6 citations
Quantum states of light have been shown to enhance precision in absorption estimation over classical strategies. By exploiting interference and resonant enhancement effects, we show that coherent-state probes in all-pass ring resonators can outperform any quantum probe single-pass strategy even when normalized by the mean input photon number. We also find that under optimal conditions coherent-state probes equal the performance of arbitrarily bright pure single-mode squeezed probes in all-pass ring resonators.
Abstract Two-photon absorption (TPA) is a nonlinear optical process with wide-ranging applications from spectroscopy to super-resolution imaging. Despite this, the precise measurement and characterisation of TPA parameters are challenging due to their inherently weak nature. We study the potential of single-mode quantum light to enhance TPA parameter estimation through the quantum Fisher information (QFI). Discrete variable quantum states (defined to be a finite superposition of Fock states) are optimised to maximise the QFI for given absorption, revealing a quantum advantage compared to both the coherent state (classical) benchmark and the single-mode squeezed vacuum state. For fixed average energy n ¯ ∈ 2 N , the Fock state is shown to be optimal for large TPA parameters, while a superposition of vacuum and a particular Fock state is optimal for small absorption for all n ¯ . This differs from single-photon absorption where the Fock state is always optimal. Notably, photon counting is demonstrated to offer optimal or nearly optimal performance compared to the QFI bound for all levels of TPA parameters for the optimised quantum probes, and their quantum advantage is shown to be robust to single-photon loss. Our findings provide insight into known limiting behaviours of Gaussian probes and their different FI scalings under photon counting ( ∝ n ¯ 2 for squeezed vacuum states versus n ¯ 3 for coherent states). The squeezed state outperforms coherent states for small TPA parameters but underperforms in the intermediate regime, becoming comparable in the large absorption limit. This can be explained through fundamental differences between behaviours of even and odd number Fock states: the former’s QFI diverges in both large and small absorption limits, while the latter diverges only in the small absorption limit, dominating at intermediate scales.