Plasmon tunability in metallodielectric metamaterials

TL;DR

This paper investigates how the plasmonic properties of metallic nanoparticle-based metamaterials can be tuned by their composition and structure, revealing deviations from classical effective medium theories and predicting multiple plasmon modes.

Contribution

It provides a rigorous calculation of dielectric functions for various metallic nanoparticle arrangements, demonstrating the influence of filling fraction and structure on plasmon modes and challenging existing theories.

Findings

Plasmon modes depend on metal filling fraction and structure.

Deviations from Maxwell-Garnett theory occur at high metal fractions.

Multiple plasmon modes are predicted in these metamaterials.

Abstract

The dielectric properties of metamaterials consisting of periodically arranged metallic nanoparticles of spherical shape are calculated by rigorously solving Maxwell's equations. Effective dielectric functions are obtained by comparing the reflectivity of planar surfaces limiting these materials with Fresnel's formulas for equivalent homogeneous media, showing mixing and splitting of individual-particle modes due to inter-particle interaction. Detailed results for simple cubic and fcc crystals of aluminum spheres in vacuum, silver spheres in vacuum, and silver spheres in a silicon matrix are presented. The filling fraction of the metal f is shown to determine the position of the plasmon modes of these metamaterials. Significant deviations are observed with respect to Maxwell-Garnett effective medium theory for large f, and multiple plasmons are predicted to exist in contrast to Maxwell-Garnett theory.