Transformation-optics description of plasmonic nanostructures containing blunt edges/corners : from symmetric to asymmetric edge rounding

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

33 Scopus Citations
View graph of relations



Original languageEnglish
Pages (from-to)6492-6506
Journal / PublicationACS Nano
Issue number7
Online published19 Jun 2012
Publication statusPublished - 24 Jul 2012
Externally publishedYes


The sharpness of corners/edges can have a large effect on the optical responses of metallic nanostructures. Here we deploy the theory of transformation optics to analytically investigate a variety of blunt plasmonic structures, including overlapping nanowire dimers and crescent-shaped nanocylinders. These systems are shown to support several discrete optical modes, whose energy and line width can be controlled by tuning the nanoparticle geometry. In particular, the necessary conditions are highlighted respectively for the broadband light absorption effect and the invisibility dips that appear in the radiative spectrum. More detailed discussions are provided especially with respect to the structures with asymmetric edge rounding. These structures can support additional subradiant modes, whose interference with the neighboring dipolar modes results in a rapid change of the scattering cross-section, similar to the phenomenon observed in plasmonic Fano resonances. Finite element numerical calculations are also performed to validate the analytical predictions. The physical insights into blunt nanostructures presented in this work may be of great interest for the design of broadband light-harvesting devices, invisible and noninvasive biosensors, and slowing-light devices.

Research Area(s)

  • blunt nanostructures, broadband light harvesting, Fano resonance, plasmonics, transformation optics