Intra-particle coupling and plasmon tuning of multilayer Au/dielectric/Au nanocrescents adhered to a dielectric cylinder

Kaiyu Wu, Xiu Lan Cheng, Luke P. Lee

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

A 3D numerical study on surface plasmon resonance is presented for a multilayer Au/dielectric/Au nanocrescent structure adhered to a dielectric cylinder. Investigations are carried out on the structures coupling modes, local field enhancement (LFE) and plasmon tuning capability. The cavity coupling via the cylinder is found to be dominant in tuning the plasmon wavelength. This provides the possibility of tailoring the devices plasmon band by adjusting the cylinders size and material. By using a cylinder with higher permittivity, the plasmon peak significantly shifts to the near- or mid-infrared regime without increasing the size of the crescents, thus increase of radiation loss can be fully avoided. Extra crescent layers can also be added to the structure to induce intra-particle couplings among Au crescents and enlarge the areas of the hot-spots, without shifting the plasmon band. The LFE of the multiple-layer structure is shown to be dramatically increased through the intra-particle coupling among the Au crescents, compared with a single layer Au nanocrescent structure. Further increase of LFE can be achieved by substituting semiconductors for the dielectrics in the structure due to the charge transport at metalsemiconductor interfaces.
Original languageEnglish
JournalNanotechnology
Volume23
Issue number5
Pages (from-to)055201
Number of pages10
ISSN0957-4484
DOIs
Publication statusPublished - 2012
Externally publishedYes

Keywords

  • Cylinders (shapes)
  • Dielectric devices
  • Dielectric materials
  • Gold
  • Multilayers
  • Surface plasmon resonance
  • Plasmons
  • Coupling mode
  • Dielectric cylinder
  • Hotspots
  • Local field enhancement
  • Metal semiconductor interface
  • Midinfrared
  • Multiple-layer structures
  • Numerical studies
  • Plasmon band
  • Plasmon peaks
  • Plasmon wavelength
  • Radiation loss
  • Single layer
  • Tuning capability

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