Fabrication of elliptical nanorings with highly tunable and multiple plasmonic resonances

Yangjun Cai, Yang Li, Peter Nordlander, Paul S. Cremer

Research output: Contribution to journalArticlepeer-review

64 Scopus citations


Herein, a new and facile patterning method is demonstrated for the scalable fabrication of gold elliptical rings (ERs) in a controlled manner over large areas. In this method, well-ordered hexagonally arrayed polystyrene (PS) rings, fabricated by colloidal lithography, were used as masters to generate poly(dimethylsiloxane) (PDMS) stamps with circular apertures. The stamps were then stretched and utilized as molds for creating elliptical PS rings by a capillary filling process. Through subsequent reactive ion etching and chemical wet-etching, the elliptical PS rings could be readily transferred into an underlying gold film, leading to the formation of gold ERs. Since the aspect ratio (AR) of the elliptical PS rings could be controlled by varying the applied strain during the capillary filling process, gold ERs with different ARs could be fabricated in a scalable manner. The optical properties of the gold ERs were characterized by UV-vis/NIR and IR extinction measurements. The ERs exhibited only odd modes of polarization-dependent plasmonic resonances at normal incidence. The experiments and corresponding theoretical studies illustrated that all resonant modes could be tuned across a broad spectral range from the visible to the mid infrared (550-4700 nm) by simply varying the AR of the ERs. Moreover, the experimental data were confirmed by COMSOL simulations.

Original languageEnglish (US)
Pages (from-to)4881-4888
Number of pages8
JournalNano letters
Issue number9
StatePublished - Sep 12 2012

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics
  • Mechanical Engineering


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