Heralded generation of single photons entangled in multiple temporal modes with controllable waveforms

TL;DR

This paper proposes a heralded, tunable source of single photons entangled across multiple temporal modes with controllable waveforms, suitable for long-distance quantum communication.

Contribution

It introduces a method to generate and control multi-time-bin entangled single photons using atomic ensembles and Raman scattering, with a scheme to measure phase coherence.

Findings

Successful generation of entangled photons in multiple time bins.

Controlled waveforms of photon time bins via read pulse parameters.

Potential application in long-distance quantum communication.

Abstract

Time-bin entangled single-photons are highly demanded for long distance quantum communication. We propose a heralded source of tunable narrowband single photons entangled in well-separated multiple temporal modes (time bins) with controllable amplitudes. The detection of a single Stokes photon generated in a cold atomic ensemble via Raman scattering of a weak write pulse heralds the preparation of one spin excitation stored within the atomic medium. A train of read laser pulses deterministically converts the atomic excitation into a single anti-Stokes photon delocalized in multi-time-bins. The waveforms of bins are well-controlled by the read pulse parameters. A scheme to measure the phase coherence across all time bins is suggested.