Photoneutralization of charges in GaAs quantum dot based entangled photon emitters

TL;DR

This study demonstrates that photoneutralization using a tunable gate laser can suppress blinking in GaAs quantum dot entangled photon emitters, significantly improving their quantum efficiency for scalable quantum network applications.

Contribution

It introduces a method to actively control charge capture and suppress blinking in GaAs quantum dots, enhancing their emission stability and efficiency.

Findings

Blinking caused by Coulomb blockade can be suppressed.

Quantum efficiency increased by 30%.

Emission stability improved for quantum network use.

Abstract

Semiconductor-based emitters of pairwise photonic entanglement are a promising constituent of photonic quantum technologies. They are known for the ability to generate discrete photonic states on-demand with low multiphoton emission, near-unity entanglement fidelity, and high single photon indistinguishability. However, quantum dots typically suffer from luminescence blinking, lowering the efficiency of the source and hampering their scalable application in quantum networks. In this paper, we investigate and adjust the intermittence of the neutral exciton emission in a GaAs/AlGaAs quantum dot under two-photon resonant excitation of the neutral biexciton. We investigate the spectral and quantum optical response of the quantum dot emission to an additional wavelength tunable gate laser, revealing blinking caused by the intrinsic Coulomb blockade due to charge capture processes. Our finding demonstrates that the emission quenching can be actively suppressed by controlling the balance of free electrons and holes in the vicinity of the quantum dot and thereby significantly increasing the quantum efficiency by 30%.