Experimental generation of single photons via active multiplexing

TL;DR

This paper demonstrates an experimental scheme to generate on-demand single photons by actively multiplexing multiple heralded sources, achieving higher output rates while maintaining photon quality, advancing quantum information processing capabilities.

Contribution

The paper introduces a practical active multiplexing scheme using four SPDC sources, an ultrafast router, and feed-forward control to enhance single-photon generation efficiency.

Findings

Fourfold increase in photon output rate.

Maintained photon indistinguishability confirmed by Hong-Ou-Mandel interference.

Numerical simulations suggest multiplexing outperforms photon-number-resolving detectors.

Abstract

An on-demand single-photon source is a fundamental building block in quantum science and technology. We experimentally demonstrate the proof of concept for a scheme to generate on-demand single photons via actively multiplexing several heralded photons probabilistically produced from pulsed spontaneous parametric down-conversions (SPDCs). By utilizing a four-photon-pair source, an active feed-forward technique, and an ultrafast single-photon router, we show a fourfold enhancement of the output photon rate. Simultaneously, we maintain the quality of the output single-photon states, confirmed by correlation measurements. We also experimentally verify, via Hong-Ou-Mandel interference, that the router does not affect the indistinguishability of the single photons. Furthermore, we give numerical simulations, which indicate that photons based on multiplexing of four SPDC sources can outperform the heralding based on highly advanced photon-number-resolving detectors. Our results show a route for on-demand single-photon generation and the practical realization of scalable linear optical quantum information processing.