Non-classical photon streams using rephased amplified spontaneous emission

TL;DR

This paper develops a quantum mechanical model of rephased photon echoes that exhibit nonclassical correlations, potentially advancing quantum repeater technology by harnessing amplified spontaneous emission noise as a resource.

Contribution

It introduces a fully quantum treatment of rephased photon echoes, revealing their nonclassical properties and proposing a wideband DLCZ protocol variant.

Findings

Rephased photon echoes show nonclassical correlations.

Amplified spontaneous emission noise can be harnessed as a quantum resource.

A new wideband quantum repeater protocol is proposed.

Abstract

We present a fully quantum mechanical treatment of optically rephased photon echoes. These echoes exhibit noise due to amplified spontaneous emission, however this noise can be seen as a consequence of the entanglement between the atoms and the output light. With a rephasing pulse one can get an "echo" of the amplified spontaneous emission, leading to light with nonclassical correlations at points separated in time, which is of interest in the context of building wide bandwidth quantum repeaters. We also suggest a wideband version of DLCZ protocol based on the same ideas.