Subwavelength Hexahedral Plasmonic Scatterers: History, Symmetries, and Resonant Characteristics

Abstract

In this work, we investigate the resonant characteristics of hexahedral (cubical) inclusions at the plasmonic domain. After an introduction to the notion of superquadric surfaces, i.e., surfaces that model various versions of a rounded cube, we present the main resonant spectrum and the surface distributions for two particular cases of a smooth and a sharp cube in the plasmonic domain. We present a historical comparative overview of the main contributions available since the 1970s. A new categorization scheme of the resonances of a cube is introduced, based on symmetry considerations. The obtained results are compared against several recent works, exposing that the higher-order modes are extremely susceptible to both the choice of sharpness of the cube and the modeling mesh. This work can be readily used as a reference for both historical and contemporary studies of the plasmonic aspects of a cube.

Facet-Enhanced Dielectric Sensitivity in Plasmonic Metal Oxide Nanocubes

“…Consistent with previous studies of plasmonic nanocubes, FEM field intensity maps show that the three modes observed in the spectral line shape correspond to dipolar resonances associated with the corners, edges, and faces (Figure c) , with the surface charge distribution consistent with three of the six main bright resonances that have been calculated for nanocubes (Figure S3). − Mimicking the experimental measurements, the refractive index of the nanocube surroundings was systematically varied, the three optical extinction peaks were deconvoluted (Figure S4 and Table S3), and a linear fit was used to determine the theoretical RIS (Figure S5 and Table S4). For comparison, the same dielectric function was used to calculate the theoretical RIS of a nanosphere.…”