Near-field localization by two dimensional metallic nano-post arrays with ultrashort light pulses

Hongki Lee, Chulhong Kim, Donghyun Kim

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Locally amplified near-fields can be induced with nanostructures within a sub-diffraction-limited volume, which is useful for biomedical imaging and sensing applications. Employment of field localization in the biomedical applications where the pulsed light is used necessitates the spatial and temporal characteristics of fields near nanostructures. We considered the gold nano-post arrays of three different shapes to localize the near-fields which are circular, rhombic, and triangular. They were modeled to be located on an ITO film and a quartz substrate with periods changing from 300 to 900 nm by 200 nm. Their size changes from 50 to 250 nm which corresponds to the radius for the case of circular nanoposts and the distance between the center and the vertices for equilateral rhombic and triangular nanoposts. Numerical calculation of near-fields at the top of nanoposts was performed with finite difference time domain method when the Gaussian pulses at center wavelengths of 532, 633, and 850 nm were normally incident. Near-fields localization occurred mainly at vertices of the nanoposts, which makes the triangular nanoposts of primary interest with an observation of the strongest field intensity within a diffraction limited field-of-view. The observed fields on the triangular vertices were enhanced by 7.85, 51.54, and 7268 when the center wavelengths were 532, 633, and 850 nm respectively. Their temporal peaks were delayed by 2.05, 4.03, and 14.49 fs, which indicates the correlation between field enhancement and time delay associated with electron damping process. It was shown that with rhombic and triangular nanoposts fields can be localized below 10 nm on vertices and their signal-to-noise ratio increased with a larger period.

Original languageEnglish
Title of host publicationPlasmonics in Biology and Medicine XIII
EditorsKrishanu Ray, Tuan Vo-Dinh, Ho-Pui A. Ho, Joseph R. Lakowicz
ISBN (Electronic)9781628419580
Publication statusPublished - 2016
EventPlasmonics in Biology and Medicine XIII - San Francisco, United States
Duration: 2016 Feb 152016 Feb 16

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
ISSN (Print)1605-7422


OtherPlasmonics in Biology and Medicine XIII
Country/TerritoryUnited States
CitySan Francisco

Bibliographical note

Publisher Copyright:
© 2016 SPIE.

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Biomaterials
  • Radiology Nuclear Medicine and imaging


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