High-brightness single photon source from a quantum dot in a directional-emission nanocavity

TL;DR

This paper presents a quantum dot-based single photon source with enhanced brightness and collection efficiency using a directional-emission photonic crystal cavity, achieving significant improvements in emission rate and collection compared to standard designs.

Contribution

The study introduces a novel cavity design that significantly enhances emission rate and collection efficiency of single photons from quantum dots.

Findings

Lifetime reduced to 45ps on resonance

Collection efficiency improved by a factor of 6

Emission antibunching with g(2)=0.05

Abstract

We analyze a single photon source consisting of an InAs quantum dot coupled to a directional-emission photonic crystal (PC) cavity implemented in GaAs. On resonance, the dot's lifetime is reduced by more than 10 times, to 45ps. Compared to the standard three-hole defect cavity, the perturbed PC cavity design improves the collection efficiency into an objective lens (NA=0.75) by factor 6, and improves the coupling efficiency of the collected light into a single mode fiber by factor 1.9. The emission frequency is determined by the cavity mode, which is antibunched to g(2)=0.05. The cavity design also enables efficient coupling to a higher-order cavity mode for local optical excitation of cavity-coupled quantum dots.