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

arXiv:1912.12087 · Optics Express

Tracking the polarisation state of light via Hong-Ou-Mandel interferometry

Natapon Harnchaiwat, Feng Zhu, Niclas Westerberg, Erik M. Gauger, Jonathan Leach

Published Dec 23, 2019• 32 citations
arXivHTMLPDF

Abstract

We provide a statistically robust and accurate framework to measure and track the polarisation state of light employing Hong-Ou-Mandel interference. This is achieved by combining the concepts of maximum likelihood estimation and Fisher information applied to photon detection events. Such an approach ensures that the Cramér-Rao bound is saturated and changes to the polarisation state are established in an optimal manner. Using this method, we show that changes in the linear polarisation state can be measured with 0.6 arcminute precision (0.01 degrees).

DOI
10.1364/oe.382622

Related papers

Optimal Measurement of Telecom Wavelength Single Photon Polarisation via Hong-Ou-Mandel Interferometry

Fabrizio Sgobba, Deborah Katia Pallotti, Arianna Elefante +4 more

The use of statistical estimation theory to boost the metrological performance of the measurement apparatus is becoming increasingly popular in a wide range of applications. Recently, such an approach has been adopted in Hong Ou Mandel interferometry, setting a new record in time delay and polarization measurement. Here, we extend these pioneering experiments in the telecom range to unlock the full potential of the information-based approach combined with a versatile spectral range, aiming for its adoption in fiber-coupled devices of up to hundreds of kilometers long as bobines or optical networks. Our measurement saturates the Cramér-Rao bound and in a long lasting experiment returns an Allan deviation of the polarization angle of 0.002 degs in 1 h of integration time.

Photonics•Jan 9, 2023•10 citations

Photon Phase Delay Sensing with Sub-Attosecond Uncertainty

Fabrizio Sgobba, Andrea Andrisani, Luigi Santamaria Amato

The application of statistical estimation theory to Hong-Ou-Mandel interferometry led to enticing results in terms of the detection limit for photon reciprocal delay and polarisation measurement. In the following paper, a fully fibre-coupled setup operating in the telecom wavelength region proves to achieve, for the first time, in common-path Hong-Ou-Mandel-based interferometry, a detection limit for photon phase delay at the zeptosecond scale. The experimental results are then framed in a theoretical model by calculating the Cramer-Rao bound (CRB) and, after comparison with the obtained experimental results, it is shown that our setup attains the optimal measurement, nearly saturating CRB.

Sensors•Mar 29, 2024•4 citations

Density matrix reconstruction using a Hong–Ou–Mandel quantum interferometer

Vitaly Sukharenko, R. Dorsinville

We provide a comprehensive analysis of the reconstruction of the density matrix for entangled photon pairs, utilizing polarization measurements within a Hong-Ou-Mandel (HOM) interference framework. The purpose of this study is to develop a new efficient approach for quantum state characterization, leveraging quantum interference to reduce wave dispersion and utilizing the maximum likelihood method for density matrix reconstruction. The model involves projecting the entangled photons onto a set of sixteen unique polarization states, enabling the observation of detailed quantum interference patterns. We use these patterns to reconstruct the density matrix, revealing the system’s quantum state and degree of entanglement. Our findings demonstrate the effectiveness of this method in accurately characterizing the quantum state of light, while leveraging quantum interference to reduce wave dispersion and improve signal quality and resolution. Our study underscores the effectiveness of this method in accurately characterizing the quantum state of light and highlights the essential role of precise density matrix reconstruction in a Hong-Ou-Mandel interferometer without the use of polarizers. The methodology and results presented lay a strong foundation for further research, with implications for improving measurement accuracy and exploring more complex quantum systems in various quantum information applications. • Density matrix of entangled photon pairs using Hong-Ou-Mandel interference profiles. • Quantum interference and density matrix improve signal quality. • Density matrix is reconstructed using HOM interference and maximum likelihood. • Theoretical study on quantum state reconstruction and its role in quantum information.

Optik•Mar 11, 2025•0 citations

Quantum Limits in Precision Hong-Ou-Mandel Interferometry

Kyle M. Jordan, Raphael A. Abrahão, Jeff S. Lundeen

We examine the precision limits of Hong-Ou-Mandel interferometry-based timing measurements using the Cramér-Rao bounds. We show how to adapt the method for realistic sources of photon pairs involving unequal mode bandwidths and nonmaximal frequency correlations.

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

High precision metrology from the fisher information of a Hong-Ou-Mandel interferometer

Ashley Lyons, George C. Knee, Eliot Bolduc +4 more

Quantum interference forces two indistinguishable input photons to depart a beamsplitter in the same (of two possible) spatial output modes; this is known as the Hong-Ou-Mandel (HOM) effect. It provides a quantitative way of measuring the distinguishability between two photons and also has been utilised to determine their relative temporal delays [1, 2]. HOM interferometry offers numerous advantages over its classical counterpart, most importantly it lacks any dependence on the phase of the photons and therefore can potentially provide reliable measurements in environments where the phase is unstable. To date there have been very few investigations on the precision that is achievable with HOM interferometry. Experiments with collinear geometries have yielded sensitivities as low as 0.1fs however these approaches are limited to measurements of birefringence and other polarisation dependent effects [3, 4], as the precision derives from the inherently stable shared path of the photon pairs. Typical non-shared path HOM interferometers exhibit resolution of roughly 1–3 fs (0.3–1 μm).

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 1, 2017•0 citations

Quantum Imaging of Birefringent Samples using Hong-Ou-Mandel Interference

Carolina Gonçalves, Tiago D. Ferreira, Catarina S. Monteiro +1 more

Two-photon interference in a Hong-Ou-Mandel (HOM) interferometer can be used as a quantum sensing mechanism due to the sensitivity of the interference dip to perturbations of the photon indistinguishability. In particular, recent works have generalized this concept to microscopy setups, but the sensitivity to optical path differences constrains its application to samples with thickness variation typically below a few micrometers if tracking changes in the coincidences at a fixed delay. Extending the concept to polarization microscopy and circumventing this limitation, this manuscript explores the use of a narrowband photon pair source with coherence length >1 mm to broaden the HOM dip. Thus, realistic sample-thickness variations introduce negligible temporal distinguishability, and changes in coincidence rate at the dip centre are then dominated by sample-induced polarization effects. To compute the polarization rotation, we develop a statistical model for the interferometer, derive the Fisher information, and establish a maximum-likelihood estimator for the local fast-axis angle. Recording dip and baseline frames at each sample position via raster scanning, the experimental results validate the framework, agreeing with classical polarized-intensity images while demonstrating operation at a maximum-precision regime and insensitiveness to layer thickness. Overall, the approach enclosed provides a quantum-based quantitative imaging of birefringent structures, which can motivate further advantageous applications, including enhanced signal-to-noise ratio and lower damage imaging of photosensitive samples.

quant-pharXiv:2512.19637•Dec 23, 2025•0 citations
We provide a statistically robust and accurate framework to measure and track the polarisation state of light employing Hong-Ou-Mandel interference. This is achieved by combining the concepts of maximum likelihood estimation and Fisher information applied to photon detection events. Such an approach ensures that the Cramér-Rao bound is saturated and changes to the polarisation state are established in an optimal manner. Using this method, we show that changes in the linear polarisation state can be measured with 0.6 arcminute precision (0.01 degrees).
The use of statistical estimation theory to boost the metrological performance of the measurement apparatus is becoming increasingly popular in a wide range of applications. Recently, such an approach has been adopted in Hong Ou Mandel interferometry, setting a new record in time delay and polarization measurement. Here, we extend these pioneering experiments in the telecom range to unlock the full potential of the information-based approach combined with a versatile spectral range, aiming for its adoption in fiber-coupled devices of up to hundreds of kilometers long as bobines or optical networks. Our measurement saturates the Cramér-Rao bound and in a long lasting experiment returns an Allan deviation of the polarization angle of 0.002 degs in 1 h of integration time.
The application of statistical estimation theory to Hong-Ou-Mandel interferometry led to enticing results in terms of the detection limit for photon reciprocal delay and polarisation measurement. In the following paper, a fully fibre-coupled setup operating in the telecom wavelength region proves to achieve, for the first time, in common-path Hong-Ou-Mandel-based interferometry, a detection limit for photon phase delay at the zeptosecond scale. The experimental results are then framed in a theoretical model by calculating the Cramer-Rao bound (CRB) and, after comparison with the obtained experimental results, it is shown that our setup attains the optimal measurement, nearly saturating CRB.
We provide a comprehensive analysis of the reconstruction of the density matrix for entangled photon pairs, utilizing polarization measurements within a Hong-Ou-Mandel (HOM) interference framework. The purpose of this study is to develop a new efficient approach for quantum state characterization, leveraging quantum interference to reduce wave dispersion and utilizing the maximum likelihood method for density matrix reconstruction. The model involves projecting the entangled photons onto a set of sixteen unique polarization states, enabling the observation of detailed quantum interference patterns. We use these patterns to reconstruct the density matrix, revealing the system’s quantum state and degree of entanglement. Our findings demonstrate the effectiveness of this method in accurately characterizing the quantum state of light, while leveraging quantum interference to reduce wave dispersion and improve signal quality and resolution. Our study underscores the effectiveness of this method in accurately characterizing the quantum state of light and highlights the essential role of precise density matrix reconstruction in a Hong-Ou-Mandel interferometer without the use of polarizers. The methodology and results presented lay a strong foundation for further research, with implications for improving measurement accuracy and exploring more complex quantum systems in various quantum information applications. • Density matrix of entangled photon pairs using Hong-Ou-Mandel interference profiles. • Quantum interference and density matrix improve signal quality. • Density matrix is reconstructed using HOM interference and maximum likelihood. • Theoretical study on quantum state reconstruction and its role in quantum information.
Quantum interference forces two indistinguishable input photons to depart a beamsplitter in the same (of two possible) spatial output modes; this is known as the Hong-Ou-Mandel (HOM) effect. It provides a quantitative way of measuring the distinguishability between two photons and also has been utilised to determine their relative temporal delays [1, 2]. HOM interferometry offers numerous advantages over its classical counterpart, most importantly it lacks any dependence on the phase of the photons and therefore can potentially provide reliable measurements in environments where the phase is unstable. To date there have been very few investigations on the precision that is achievable with HOM interferometry. Experiments with collinear geometries have yielded sensitivities as low as 0.1fs however these approaches are limited to measurements of birefringence and other polarisation dependent effects [3, 4], as the precision derives from the inherently stable shared path of the photon pairs. Typical non-shared path HOM interferometers exhibit resolution of roughly 1–3 fs (0.3–1 μm).
Two-photon interference in a Hong-Ou-Mandel (HOM) interferometer can be used as a quantum sensing mechanism due to the sensitivity of the interference dip to perturbations of the photon indistinguishability. In particular, recent works have generalized this concept to microscopy setups, but the sensitivity to optical path differences constrains its application to samples with thickness variation typically below a few micrometers if tracking changes in the coincidences at a fixed delay. Extending the concept to polarization microscopy and circumventing this limitation, this manuscript explores the use of a narrowband photon pair source with coherence length >1 mm to broaden the HOM dip. Thus, realistic sample-thickness variations introduce negligible temporal distinguishability, and changes in coincidence rate at the dip centre are then dominated by sample-induced polarization effects. To compute the polarization rotation, we develop a statistical model for the interferometer, derive the Fisher information, and establish a maximum-likelihood estimator for the local fast-axis angle. Recording dip and baseline frames at each sample position via raster scanning, the experimental results validate the framework, agreeing with classical polarized-intensity images while demonstrating operation at a maximum-precision regime and insensitiveness to layer thickness. Overall, the approach enclosed provides a quantum-based quantitative imaging of birefringent structures, which can motivate further advantageous applications, including enhanced signal-to-noise ratio and lower damage imaging of photosensitive samples.