Excitation of confined modes on particle arrays

TL;DR

This paper combines theoretical and experimental approaches to study confined plasmonic modes in gold nanodisk arrays, demonstrating their potential for optical applications through observed long-range propagation and strong extinction features.

Contribution

It provides the first detailed experimental and theoretical analysis of confined modes in ordered gold nanodisk arrays embedded in silica.

Findings

Excellent agreement between theory and experiment in mode dispersion

Modes exhibit long propagation distances

Deep extinction features observed in reflectivity

Abstract

We describe both theoretically and experimentally the existence and excitation of confined modes in planar arrays of gold nanodisks. Ordered 2D lattices of monodispersive nanoparticles are manufactured, embedded in a silica matrix, and exposed to evanescent prism-coupling illumination, leading to dark features in the reflectivity, which signal the presence of confined modes guided along the arrays. We find remarkable agreement between theory and experiment in the frequency-momentum dispersion of the resonances. Direct excitation of these modes reveals long propagation distances and deep extinction features. This characterization of guided modes shows the great potential of metallic particle arrays for optical signal processing and distant sensing applications.