Decay dynamics of quantum dots influenced by the local density of optical states of two-dimensional photonic crystal membranes

TL;DR

This study investigates how the local density of optical states in two-dimensional photonic crystal membranes affects the decay dynamics of InAs quantum dots, revealing emission rate modifications near band edges and within the bandgap.

Contribution

It provides experimental evidence of decay rate control of quantum dots by photonic crystal bandgap tuning, aligning with theoretical local density of states predictions.

Findings

Quantum dots' emission slows near the bandgap edges.

Enhanced emission observed at the bandgap edges.

Strong inhibition of emission inside the bandgap.

Abstract

We have performed time-resolved spectroscopy on InAs quantum dot ensembles in photonic crystal membranes. The influence of the photonic crystal is investigated by varying the lattice constant systematically. We observe a strong slow down of the quantum dots' spontaneous emission rates as the two-dimensional bandgap is tuned through their emission frequencies. The measured band edges are in full agreement with theoretical predictions. We characterize the multi-exponential decay curves by their mean decay time and find enhancement of the spontaneous emission at the bandgap edges and strong inhibition inside the bandgap in good agreement with local density of states calculations.