Antenna-cavity hybrids: matching polar opposites for Purcell enhancements at any linewidth

TL;DR

This paper introduces a hybrid cavity-antenna system that surpasses individual components in emission enhancement, offering tunable bandwidth and high efficiency for quantum light-matter interactions.

Contribution

It presents a fully analytical model for hybrid systems, revealing mechanisms behind boosted emission and demonstrating their advantages over standalone cavities or antennas.

Findings

Hybrid systems achieve stronger emission enhancement than individual cavity or antenna.

The model accurately predicts enhancement spectra matching finite-element simulations.

Hybrid systems can maintain high outcoupling efficiency while boosting emission.

Abstract

Strong interaction between light and a single quantum emitter is essential to a great number of applications, including single photon sources. Microcavities and plasmonic antennas have been used frequently to enhance these interactions through the Purcell effect. Both can provide large emission enhancements: the cavity typically through long photon lifetimes (high $Q$), and the antenna mostly through strong field enhancement (low mode volume $V$). In this work, we demonstrate that a hybrid system, which combines a cavity and a dipolar antenna, can achieve stronger emission enhancements than the cavity or antenna alone. We show that such systems can be used as a versatile platform to tune the bandwidth of enhancement to any desired value, while simultaneously boosting emission enhancement. Our fully consistent analytical model allows to identify the underlying mechanisms of boosted emission enhancement in hybrid systems, which include radiation damping and constructive interference between multiple-scattering paths. Additionally, we find excellent agreement between strongly boosted enhancement spectra from our analytical model and from finite-element simulations on a realistic cavity-antenna system. Finally, we demonstrate that hybrid systems can simultaneously boost emission enhancement and maintain a near-unity outcoupling efficiency into a single cavity decay channel, such as a waveguide.