Visible-to-telecom quantum frequency conversion of light from a single quantum emitter

TL;DR

This paper demonstrates efficient quantum frequency conversion of single photons emitted by a quantum dot from visible to telecom wavelengths, preserving quantum properties and advancing quantum communication technologies.

Contribution

It presents the first high-efficiency (>30%) QFC of single photons from a quantum dot to telecom wavelengths with preserved coherence and antibunching.

Findings

Achieved >30% conversion efficiency.

Preserved coherence time and photon antibunching.

Shows potential for quantum repeater integration.

Abstract

Quantum frequency conversion (QFC), a nonlinear optical process in which the frequency of a quantum light field is altered while conserving its non-classical correlations, was first demonstrated 20 years ago. Meanwhile, it is considered an essential tool for the implementation of quantum repeaters since it allows for interfacing quantum memories with telecom-wavelength photons as quantum information carriers. Here we demonstrate efficient (>30%) QFC of visible single photons (711 nm) emitted by a quantum dot (QD) to a telecom wavelength (1,313 nm). Analysis of the first and second-order coherence before and after wavelength conversion clearly proves that important properties, such as the coherence time and photon antibunching, are fully conserved during the frequency translation process. Our findings underline the great potential of single photon sources on demand in combination with QFC as a promising technique for quantum repeater schemes.