Localization characteristics of two-dimensional quasicrystals consisting of metal nanoparticles

TL;DR

This study explores the localization and radiation properties of plasmonic modes in a 2D quasicrystalline array of metal nanoparticles using eigen-decomposition, revealing highly localized anti-phase ring modes with high fidelity.

Contribution

It introduces a trajectory map method to analyze complex plasmonic modes and identifies unique localized modes in quasicrystals, advancing understanding of their optical behavior.

Findings

Some modes are leaky with radiation loss.

Highly localized anti-phase ring mode has the highest fidelity.

Different localized modes exhibit varied radial decay behaviors.

Abstract

Using the eigen-decomposition method, we investigated the plasmonic modes in a two-dimensional quasicrystalline array of metal nanoparticles. Various properties of the plasmonic modes, such as their symmetry, radiation loss and spatial localization are studied. Some collective plasmonic modes are found to be leaky with out-of-plane radiation loss, but some modes can have very high fidelity. To facilitate the analysis on the complex behavior of the collective plasmonic modes, we considered a trajectory map in a three dimension parameter space defined by the frequency of the mode, the participation ratio of the mode that gives the spatial distribution, and the eigenvalue that is related to the inverse lifetime of the mode. With the help of the trajectory map method, we found that there are modes that are localized in some special ways and the plasmonic mode with highest spatial localization and highly fidelity is found to be a type of anti-phase ring mode. In general, different localized modes have very different radial decay behaviors. There is no special relationship between the fidelity of the modes and their spatial localization.