Boosting and Localizing Near-Field in Plasmonic Mirror-Image Nanoepsilon

Jia Yu Lin, Po-Tsung Lee*

*Corresponding author for this work

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

A novel plasmonic mirror-image nanoepsilon (MINE) structure is studied to achieve significantly enhanced and localized near-field. It is well-known that the nanorod dimer is able to gain a high local field at the center of the structure by adjusting its rod width, rod length, and gap distance. When adopting an auxiliary nanoring structure electron reservoirs surrounding the nanorod-dimer to form the MINE structure, the local field can be further enhanced owing to a large amount of charges into sharp dimer structure which can confine the accumulation of charges to apexes. Thus, better synergistic interaction of gap effect and lightning-rod effect can be achieved for high field enhancement around nanoscale gap. The symmetric mode in the MINE structure enables strong near-field with a concentrated distribution around the gap. The influences of rod-tip angle and gap distance on the optical properties of plasmonic MINE structures are numerically investigated. With reducing the rod-tip angle and gap distance, considerable enhancements on the field intensities at the rod tips and the gap center can be attributed to the improved lightning-rod and gap effects. The near-field intensities at the rod tip and gap center are dramatically enlarged ~1.94 × 104 and ~1.41 × 104 times with the rod-tip angle of 41° and gap distance of 10 nm, and the near-field is localized within an extremely small range. These features are very beneficial for various plasmonic applications.

Original languageEnglish
Pages (from-to)81-89
Number of pages9
JournalPlasmonics
Volume13
Issue number1
DOIs
StatePublished - 1 Feb 2018

Keywords

  • Gap effects
  • Hybrid nanostructures
  • Lightning-rod
  • Localized surface plasmon resonance
  • Nanoring
  • Nanorod dimer
  • Near-field enhancement

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