Plasmonic Antennas Hybridized with Dielectric Waveguides

TL;DR

This paper investigates hybrid plasmonic-dielectric waveguide antennas, demonstrating their spectral properties, directivity, and potential for integrated quantum optics and lab-on-chip applications through experimental and theoretical analysis.

Contribution

It introduces waveguide hybridized Yagi-Uda antennas with enhanced directionality, combining plasmonics and dielectric waveguides for integrated optical applications.

Findings

Demonstrated directional out-coupling of guided modes.

Achieved directional in-coupling of localized excitations.

Validated system suitability for quantum optics and fluorescence lab-on-chip.

Abstract

For the purpose of using plasmonics in an integrated scheme where single emitters can be probed efficiently, we experimentally and theoretically study the scattering properties of single nano-rod gold antennas as well as antenna arrays placed on one-dimensional dielectric silicon nitride waveguides. Using real space and Fourier microscopy correlated with waveguide transmission measurements, we quantify the spectral properties, absolute strength and directivity of scattering. The scattering processes can be well understood in the framework of the physics of dipolar objects placed on a planar layered environment with a waveguiding layer. We use the single plasmonic structures on top of the waveguide as dipolar building blocks for new types of antennas where the waveguide enhances the coupling between antenna elements. We report on waveguide hybridized Yagi-Uda antennas which show directionality in out-coupling of guided modes as well as directionality for in-coupling into the waveguide of localized excitations positioned at the feed element. These measurements together with simulations demonstrate that this system is ideal as a platform for plasmon quantum optics schemes as well as for fluorescence lab-on-chip applications.