Mutual Coupling of two Semiconductor Quantum Dots via an Optical Nanocavity Mode

TL;DR

This study demonstrates the coherent coupling of two spatially separated quantum dots via an optical nanocavity mode, revealing tunable interactions and potential advantages for quantum systems.

Contribution

It provides both experimental and theoretical insights into the mutual coupling of quantum dots mediated by a nanocavity, including the observation of a triple-peak signature of coherent coupling.

Findings

Observation of a triple-peak during double anticrossing indicating coherent coupling.

Ability to tune quantum dots into mutual resonance using bias voltage.

Theoretical modeling of the coupled quantum dot-cavity system.

Abstract

We present an experimental and theoretical study of a system consisting of two spatially separated self-assembled InGaAs quantum dots strongly coupled to a single optical nanocavity mode. Due to their different size and compositional profiles, the two quantum dots exhibit markedly different DC Stark shifts. This allows us to tune them into mutual resonance with each other and a photonic crystal nanocavity mode as a bias voltage is varied. Photoluminescence measurements show a characteristic triple peak during the double anticrossing, which is a clear signature of a coherently coupled system of three quantum states. We fit the entire set of emission spectra of the coupled system to theory and are able to investigate the coupling between the two quantum dots via the cavity mode, and the coupling between the two quantum dots when they are detuned from the cavity mode. We suggest that the resulting quantum V-system may be advantageous since dephasing due to incoherent losses from the cavity mode can be avoided.