Generation Engineering of Heralded Narrowband Colour Entangled States

TL;DR

This paper proposes a scheme for generating heralded, narrowband, frequency-bin entangled single-photon states compatible with atomic transitions, optimizing entanglement and generation probability with minimal absorption for quantum communication.

Contribution

It introduces a novel method to engineer indistinguishability in four-wave mixing for efficient, narrowband entangled photon generation adaptable to various physical systems.

Findings

Entanglement can be optimized alongside generation probability.

The scheme maintains negligible absorption.

Versatile implementation in different physical systems.

Abstract

Efficient heralded generation of entanglement together with its manipulation is of great importance for quantum communications. In addition, states generated with bandwidths naturally compatible with atomic transitions allow a more efficient mapping of light into matter which is an essential requirement for long distance quantum communications. Here we propose a scheme where the indistinguishability between two spontaneous four-wave mixing processes is engineered to herald generation of single-photon frequency-bin entangled states, i.e., single-photons shared by two distinct frequency modes. We show that entanglement can be optimised together with the generation probability, while maintaining absorption negligible. Besides, the scheme illustrated for cold rubidium atoms is versatile and can be implemented in several other physical systems.