Imaging high-dimensional spatial entanglement with a camera

TL;DR

This paper demonstrates that modern camera technology can measure high-dimensional spatial entanglement in photon pairs, enabling the observation of EPR correlations across thousands of states with greater efficiency than traditional methods.

Contribution

It introduces the use of electron-multiplying CCD cameras for measuring spatial entanglement, surpassing single-photon detectors in capacity and scope.

Findings

Measured entanglement of around 2,500 spatial states

Observed EPR correlations exceeding previous methods by over two orders of magnitude

Showed cameras can significantly enhance quantum optics measurements

Abstract

The light produced by parametric down-conversion shows strong spatial entanglement that leads to violations of EPR criteria for separability. Historically, such studies have been performed by scanning a single-element, single-photon detector across a detection plane. Here we show that modern electron-multiplying charge-coupled device cameras can measure correlations in both position and momentum across a multi-pixel field of view. This capability allows us to observe entanglement of around 2,500 spatial states and demonstrate Einstein-Podolsky-Rosen type correlations by more than two orders of magnitude. More generally, our work shows that cameras can lead to important new capabilities in quantum optics and quantum information science.