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

Conference on Lasers and Electro-Optics

Spatial Entanglement Characterization in a Biphoton Beam

D. Korn, Dirk Puhlmann, Carsten Henkel, Robert Elsner, Martin R. Ostermeyer

Published Jan 1, 2009• 0 citations
Publisher

Abstract

Spatial entanglement is investigated for applications in quantum imaging relying on multi-photon absorption. A product of variances in space and momentum shows strong violation of the classical correlation bound.
DOI
10.1364/iqec.2009.iwc4

Related papers

Imaging High-dimensional Spaces with Spatially Entangled Photon Pairs

Matthew C. Reichert, Xiaohang Sun, Jason W. Fleischer

We directly measure the biphoton probability distribution within a 373 million dimensional Hilbert space using an electron multiplying CCD camera. These data allow for simultaneous characterization of correlations and their application for sub-diffraction-limited imaging.

Imaging and Applied Optics•Jan 1, 2016•1 citation

Demonstrating spatial entanglement for the position and momentum of laser beams

C. C. Harb, K. Wagner, Hongxin Zou +5 more

We present the latest results on the experimental generation of the position and momentum (x-p) entanglement for bright optical beams [1]. Spatial entanglement of light is a direct demonstration of entanglement of the momentum and position of laser beam as envisioned in the original publication by Einstein, Podolsky and Rosen [2]. Spatial entanglement has potential applications in quantum imaging systems and for quantum communication protocols. The position-momentum entanglement was observed in the form of the degree of inseparability, which was measured to be no larger than 0.76.

Quantum-Atom Optics Downunder (QAO)•Jan 1, 2007•0 citations

Spatial entanglement and orbital angular momentum

Martin P. van Exter, H. Di Lorenzo Pires

We review a series of experiments on spatial entanglement, both in two dimensions and in orbital angular moment. Two-photon scattering is introduced as tool to quantify the dimensionality of the entanglement and proof its purity.

Frontiers in Optics•Jan 1, 2011•0 citations

Tomography of spatially entangled biphotons

D. Korn, Dirk Puhlmann, Carsten Henkel +2 more

Correlations in light can be used for a variety of applications in metrology and imaging. Several schemes in quantum imaging rely on multi-photon absorption. Therefore a detailed knowledge of the temporal and spatial correlations of the photons used is desired. This paper investigates the correlations of space-momentum entangled biphotons generated from type II parametric down conversion. The type II generation allows for individual manipulation in each path to control the spatial modes involved in the subsequent biphoton beam creation utilizing a Hong-Ou-Mandel interference.

Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 1, 2009•0 citations

Image-Plane Detection of Spatially Entangled Photon Pairs with a CMOS Camera

David McFadden, Rainer Heintzmann

Spatially entangled photon pairs (biphotons) generated by spontaneous parametric down-conversion offer unique opportunities for quantum imaging, but image-plane biphoton correlations are difficult to observe with camera-based detectors. Previous camera-based biphoton imaging experiments have relied on photon-counting detection, which necessitates operation deep in the photon-sparse regime and requires extremely low dark rates. Here, we demonstrate the detection of spatial biphoton joint probability distributions in both the image plane and the pupil plane (also termed "near-field plane" and "far-field plane" respectively) using a conventional scientific CMOS camera operated in linear mode. We work at mesoscopic intensity levels, corresponding to a photon flux approximately four orders of magnitude higher than typical photon-counting approaches. From the measured image- and pupil plane correlations, we observe position and momentum correlations consistent with an EPR-type entanglement witness. A tailored correlation analysis suited for image plane imaging suppresses detector artifacts and intensity fluctuations, enabling acquisition with significantly fewer frames. Our results demonstrate that spatially entangled-light imaging can be performed efficiently with standard imaging hardware, extending quantum imaging techniques beyond the photon-counting regime.

quant-pharXiv:2512.24878•Jan 1, 2026•0 citations

Characterization of space-momentum entangled photons with a time resolving CMOS SPAD array

Bruno Eckmann, Bänz Bessire, Manuel Unternährer +3 more

Single-photon avalanche diode arrays can provide both the spatial and temporal information of each detected photon. We present here the characterization of spatially entangled photons with a 32 × 32 pixel sensor, specifically designed for quantum imaging applications. The sensor is time-tagging each detection event at pixel level with sub-nanosecond accuracy within frames of 50 ns. The spatial correlations between any number of detections in a defined temporal window can thus be directly extracted from the data.The space-momentum entanglement of photon pairs is demonstrated by violating an EPR-type inequality directly from the measured near-field correlations and far-field anti-correlations.

arXiv:2006.10791•Optics Express•Sep 13, 2020•25 citations
We present the latest results on the experimental generation of the position and momentum (x-p) entanglement for bright optical beams [1]. Spatial entanglement of light is a direct demonstration of entanglement of the momentum and position of laser beam as envisioned in the original publication by Einstein, Podolsky and Rosen [2]. Spatial entanglement has potential applications in quantum imaging systems and for quantum communication protocols. The position-momentum entanglement was observed in the form of the degree of inseparability, which was measured to be no larger than 0.76.
Correlations in light can be used for a variety of applications in metrology and imaging. Several schemes in quantum imaging rely on multi-photon absorption. Therefore a detailed knowledge of the temporal and spatial correlations of the photons used is desired. This paper investigates the correlations of space-momentum entangled biphotons generated from type II parametric down conversion. The type II generation allows for individual manipulation in each path to control the spatial modes involved in the subsequent biphoton beam creation utilizing a Hong-Ou-Mandel interference.
Spatially entangled photon pairs (biphotons) generated by spontaneous parametric down-conversion offer unique opportunities for quantum imaging, but image-plane biphoton correlations are difficult to observe with camera-based detectors. Previous camera-based biphoton imaging experiments have relied on photon-counting detection, which necessitates operation deep in the photon-sparse regime and requires extremely low dark rates. Here, we demonstrate the detection of spatial biphoton joint probability distributions in both the image plane and the pupil plane (also termed "near-field plane" and "far-field plane" respectively) using a conventional scientific CMOS camera operated in linear mode. We work at mesoscopic intensity levels, corresponding to a photon flux approximately four orders of magnitude higher than typical photon-counting approaches. From the measured image- and pupil plane correlations, we observe position and momentum correlations consistent with an EPR-type entanglement witness. A tailored correlation analysis suited for image plane imaging suppresses detector artifacts and intensity fluctuations, enabling acquisition with significantly fewer frames. Our results demonstrate that spatially entangled-light imaging can be performed efficiently with standard imaging hardware, extending quantum imaging techniques beyond the photon-counting regime.
Single-photon avalanche diode arrays can provide both the spatial and temporal information of each detected photon. We present here the characterization of spatially entangled photons with a 32 × 32 pixel sensor, specifically designed for quantum imaging applications. The sensor is time-tagging each detection event at pixel level with sub-nanosecond accuracy within frames of 50 ns. The spatial correlations between any number of detections in a defined temporal window can thus be directly extracted from the data.The space-momentum entanglement of photon pairs is demonstrated by violating an EPR-type inequality directly from the measured near-field correlations and far-field anti-correlations.