Enhancing the efficiency of quantum-dot-based single-photon source designs by suppressing background emission using concentric rings

TL;DR

This paper proposes a concentric ring design around nanowires and micropillars to significantly improve single-photon emission efficiency by suppressing background radiation through photonic bandgap effects.

Contribution

It introduces a novel concentric ring structure that enhances emission into the desired mode and demonstrates improved collection efficiency in practical single-photon sources.

Findings

Radiative emission fraction into fundamental mode increased to 0.999

Collection efficiency improved in tapered nanowire-based sources

Beneficial effects observed with optimized rings around micropillars

Abstract

In this paper, we theoretically demonstrate that a few-period circular Bragg reflector consisting of concentric rings placed around an infinite nanowire with an embedded quantum dot can increase the fraction of radiative emission into the fundamental $\mathrm{HE}_{11}$ mode ($\beta=\Gamma_{\rm HE_{11}}/\Gamma_{\rm Total}$) up to 0.999 due to enhanced suppression of the emission into radiation modes caused by a photonic bandgap effect. We then apply this strategy in the practically relevant case of the finite-sized single-photon source based on tapered nanowires and demonstrate that the collection efficiency can be improved. Additionally, we also show the beneficial effects of placing optimized rings around the micropillar single-photon source.