Removing a wedge from a metallic nanodisk reveals a fano resonance.

Fang, Zheyu; Cai, Junyi; Yan, Zhongbo; Nordlander, Peter; Halas, Naomi J; Zhu, Xing · Nano Lett · 2011

basic_science · Level V

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Abstract

A wide variety of complex, multicomponent plasmonic nanostructures have been shown to possess Fano resonances. Here we introduce a remarkably simple planar nanostructure, a single metallic nanodisk with a missing wedge-shaped slice, that also supports a Fano resonance. In this geometry, the Fano line shape arises from the coupling between a hybridized plasmon resonance of the disk and a narrower quadrupolar mode supported by the edge of the missing wedge slice. As a consequence, both disk size and wedge angle control the properties of the resonance. A semianalytical description of plasmon hybridization proves useful for analyzing the resulting line shape.