Quantum dot micropillar cavities with quality factors exceeding 250,000

TL;DR

This study demonstrates quantum dot micropillar cavities with record-high quality factors exceeding 250,000, achieved through specific measurement techniques, enabling enhanced light-matter interactions.

Contribution

It reveals the dependency of measured quality factors on the measurement scheme and reports record-high Q-factors in quantum dot micropillar cavities.

Findings

Photoreflectance yields higher Q-factors than photoluminescence.

Q-factors up to 184,000 observed in photoluminescence.

Q-factors exceeding 250,000 observed in reflectance spectra.

Abstract

We report on the spectroscopic investigation of quantum dot - micropillar cavities with unprecedented quality factors. We observe a pronounced dependency of the quality factor on the measurement scheme, and find that significantly larger quality factors can be extracted in photoreflectance compared to photoluminescence measurements. While the photoluminescence spectra of the microcavity resonances feature a Lorentzian lineshape and Q-factors up to 184,000, the reflectance spectra have a Fano-shaped asymmetry and feature significantly higher Q-factors in excess of 250,000 resulting from a full saturation of the embedded emitters. The very high quality factors in our cavities promote strong light-matter coupling with visibilities exceeding 0.5 for a single QD coupled to the cavity mode.