Tunable Indistinguishable Photons From Remote Quantum Dots

TL;DR

This paper demonstrates that embedding quantum dots in a quantum well structure allows for significantly increased electric field tuning, enabling the emission energies of remote quantum dots to be matched for two-photon interference.

Contribution

The study introduces a novel quantum well heterostructure to enhance electric field tuning of quantum dots, facilitating indistinguishable photon emission from remote sources.

Findings

Increased vertical electric field by over an order of magnitude.

Preservation of narrow linewidths and high quantum efficiencies.

Successful tuning of remote quantum dots for two-photon interference.

Abstract

Single semiconductor quantum dots have been widely studied within devices that can apply an electric field. In the most common system, the low energy offset between the InGaAs quantum dot and the surrounding GaAs material limits the magnitude of field that can be applied to tens of kVcm^-1, before carriers tunnel out of the dot. The Stark shift experienced by the emission line is typically 1 meV. We report that by embedding the quantum dots in a quantum well heterostructure the vertical field that can be applied is increased by over an order of magnitude whilst preserving the narrow linewidths, high internal quantum efficiencies and familiar emission spectra. Individual dots can then be continuously tuned to the same energy allowing for two-photon interference between remote, independent, quantum dots.