Quantum Transduction of Telecommunications-band Single Photons from a Quantum Dot by Frequency Upconversion

TL;DR

This paper demonstrates the frequency upconversion of single photons emitted by a quantum dot from 1.3 μm to 710 nm, preserving their quantum properties, which is crucial for quantum communication and computation.

Contribution

It is the first to transduce a true single-photon source at telecom wavelength to visible light while maintaining quantum characteristics.

Findings

Achieved 21% total detection efficiency in frequency upconversion.

Maintained quantum nature with g^(2)(0) = 0.165, indicating single-photon purity.

Demonstrated potential for integrating quantum dots with optical fiber networks.

Abstract

The ability to transduce non-classical states of light from one wavelength to another is a requirement for integrating disparate quantum systems that take advantage of telecommunications-band photons for optical fiber transmission of quantum information and near-visible, stationary systems for manipulation and storage. In addition, transducing a single-photon source at 1.3 {\mu}m to visible wavelengths for detection would be integral to linear optical quantum computation due to the challenges of detection in the near-infrared. Recently, transduction at single-photon power levels has been accomplished through frequency upconversion, but it has yet to be demonstrated for a true single-photon source. Here, we transduce the triggered single-photon emission of a semiconductor quantum dot at 1.3 {\mu}m to 710 nm with a total detection (internal conversion) efficiency of 21% (75%). We demonstrate that the 710 nm signal maintains the quantum character of the 1.3 {\mu}m signal, yielding a photon anti-bunched second-order intensity correlation, g^(2)(t), that shows the optical field is composed of single photons with g^(2)(0) = 0.165 < 0.5.