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

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.

Interference of temporally shaped single photons

“…However, the temporal purity of the single photons generated by PDC is poor, which is important in quantum information processing. On the other hand, the timebin states [26][27][28][29], which encoding information directly in time domain, is verified through single-photon interference, have potentially important application in QC and QKD [30][31][32]. The generation of multi-bins with genuine single photons is complicated in set up and of low production efficiency, and therefore the single photons are produced from attenuated laser pulses.…”