No 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.

Confining electromagnetic energy is crucial to enhance light-matter interactions, with important implications for science and technology. Here, the opportunities offered by trapping and confining light in open structures, based on the concept of embedded eigenstates within the radiation continuum enabled by zero-index metamaterials, are discussed. Building upon the physical insights offered by the analysis, a general platform is put forward that allows the realization of extremely high field enhancements in open structures under external illumination. Structures supporting embedded eigenstates represent a rare example of physical systems in which extreme-in principle unbounded-responses can be tamed. The proposed design recipe to realize bound states in the continuum also offers a simple model that allows testing of important questions that surround the concept of embedded eigenstates, such as their effect on the local density of photonic states. The findings help clarify which nano-optical and radio-wave applications may benefit from this unusual and singular response.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.