Heralded single-photon source utilizing highly nondegenerate, spectrally factorable spontaneous parametric downconversion

TL;DR

This paper demonstrates a heralded single-photon source using nondegenerate SPDC in PPKTP, achieving high purity and efficiency, suitable for quantum communication and time-multiplexed quantum photonic applications.

Contribution

It introduces a spectrally factorable, highly nondegenerate SPDC source with high purity and efficiency, advancing quantum photon source technology.

Findings

Achieved 90% purity of heralded single photons.

Demonstrated >90% heralding efficiency.

Produced photons suitable for telecom fiber transmission.

Abstract

We report on the generation of an indistinguishable heralded single-photon state, using highly nondegenerate spontaneous parametric downconversion (SPDC). Spectrally factorable photon pairs can be generated by incorporating a broadband pump pulse and a group-velocity matching (GVM) condition in a periodically-poled potassium titanyl phosphate (PPKTP) crystal. The heralding photon is in the near IR, close to the peak detection efficiency of off-the-shelf Si single-photon detectors; meanwhile, the heralded photon is in the telecom L-band where fiber losses are at a minimum. We observe spectral factorability of the SPDC source and consequently high purity (90%) of the produced heralded single photons by several different techniques. Because this source can also realize a high heralding efficiency (> 90%), it would be suitable for time-multiplexing techniques, enabling a pseudo-deterministic single-photon source, a critical resource for optical quantum information and communication technology.