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Updated: Sep 1, 2025

A Photonic System for Generating Unconditional Polarization-Entangled Photons Based on Multiple Quantum Interference
Published on: September 5, 2019
Two-colour high-purity Einstein-Podolsky-Rosen photonic state
Tulio Brito Brasil1, Valeriy Novikov2,3, Hugo Kerdoncuff4
1Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark. tulio.brasil@nbi.ku.dk.
Abstract:
We report a high-purity Einstein-Podolsky-Rosen (EPR) state between light modes with the wavelengths separated by more than 200 nm. We demonstrate highly efficient EPR-steering between the modes with the product of conditional variances [Formula: see text]. The modes display - 7.7 ± 0.5 dB of two-mode squeezing and an overall state purity of 0.63 ± 0.16. EPR-steering is observed over five octaves of sideband frequencies from RF down to audio-band. The demonstrated combination of high state purity, strong quantum correlations, and extended frequency range enables new matter-light quantum protocols.
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