Statistical measurements of quantum emitters coupled to Anderson-localized modes in disordered photonic-crystal waveguides

TL;DR

This study explores how disorder-induced Anderson-localized modes in photonic-crystal waveguides can enhance or inhibit quantum dot emission, revealing potential for quantum optics and energy applications.

Contribution

It provides the first statistical analysis of quantum emitter coupling to Anderson-localized modes, demonstrating significant Purcell factor enhancements without cavity control.

Findings

Average Purcell factor of 2 observed in disordered cavities

Maximum Purcell factor of 23.8 achieved by tuning quantum dots

Evidence of both inhibited and enhanced emission rates

Abstract

Optical nanostructures have proven to be meritorious for tailoring the emission properties of quantum emitters. However, unavoidable fabrication imperfections may represent a nuisance. Quite remarkably, disorder offers new opportunities since light can be efficiently confined by random multiple scattering leading to Anderson localization. Here we investigate the effect of such disorder-induced cavities on the emission dynamics of single quantum dots embedded in disordered photonic-crystal waveguides. We present time-resolved measurements of both the total emission from Anderson-localized cavities and from single emitters that are coupled to the cavities. We observe both strongly inhibited and enhanced decay rates relative to the rate of spontaneous emission in a homogeneous medium. From a statistical analysis, we report an average Purcell factor of 2 in without any control on the quantum dot - cavity detuning. By spectrally tuning individual quantum dots into resonance with Anderson-localized modes, a maximum Purcell factor of 23.8 is recorded, which lies at the onset of the strong coupling regime. The presented data quantify the potential of naturally occurring Anderson-localized cavities for controlling and enhancing the light-matter interaction strength, which is of relevance not only for cavity quantum-electrodynamics experiments but potentially also for efficient energy harvesting and controllable random lasing.