Efficient Spatial Redistribution of Quantum Dot Spontaneous Emission from 2D Photonic Crystals

TL;DR

This study demonstrates how 2D photonic crystals can significantly enhance the external quantum efficiency of quantum dots while reducing their spontaneous emission rate, enabling more efficient single-photon sources.

Contribution

It provides a quantitative analysis of how 2D photonic bandgaps modify spontaneous emission and improve quantum dot efficiency, advancing photonic device design.

Findings

Quantum dots in 2D photonic crystals show 5-10x efficiency enhancement.

Spontaneous emission rate is reduced by a similar factor.

Results are explained by modal redistribution of emission.

Abstract

We investigate the modification of the spontaneous emission dynamics and external quantum efficiency for self-assembled InGaAs quantum dots coupled to extended and localised photonic states in GaAs 2D-photonic crystals. The 2D-photonic bandgap is shown to give rise to a 5-10 times enhancement of the external quantum efficiency whilst the spontaneous emission rate is simultaneously reduced by a comparable factor. Our findings are quantitatively explained by a modal redistribution of spontaneous emission due to the modified local density of photonic states. The results suggest that quantum dots embedded within 2D-photonic crystals are suitable for practical single photon sources with high external efficiency.