Subgroup decomposition of plasmonic resonances in hybrid oligomers: Modeling the resonance lineshape

Mohsen Rahmani, Dangyuan Lei, Vincenzo Giannini, Boris Lukiyanchuk, Mojtaba Ranjbar, Thomas Yun Fook Liew, Minghui Hong, Stefan A. Maier

Research output: Journal article publicationJournal articleAcademic researchpeer-review

135 Citations (Scopus)

Abstract

Plasmonic resonances with a Fano lineshape observed in metallic nanoclusters often arise from the destructive interference between a dark, subradiant mode and a bright, super-radiant one. A flexible control over the Fano profile characterized by its linewidth and spectral contrast is crucial for many potential applications such as slowing light and biosensing. In this work, we show how one can easily but significantly tailor the overall spectral profile in plasmonic nanocluster systems, for example, quadrumers and pentamers, by selectively altering the particle shape without a need to change the particle size, interparticle distance, or the number of elements of the oligomers. This is achieved through decomposing the whole spectrum into two separate contributions from subgroups, which are efficiently excited at their spectral peak positions. We further show that different strengths of interference between the two subgroups must be considered for a full understanding of the resulting spectral lineshape. In some cases, each subgroup is separately active in distinct frequency windows with only small overlap, leading to a simple convolution of the subspectra. Variation in particle shape of either subgroup results in the tuning of the overall spectral lineshape, which opens a novel pathway for shaping the plasmonic response in small nanoclusters.
Original languageEnglish
Pages (from-to)2101-2106
Number of pages6
JournalNano Letters
Volume12
Issue number4
DOIs
Publication statusPublished - 11 Apr 2012
Externally publishedYes

Keywords

  • Fano resonances
  • plasmonic oligomers
  • subgroup decomposition
  • Subwavelength nanostructures
  • surface plasmons

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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