Enhanced detection sensitivity of higher-order vibrational modes of gold nanodisks on top of a GaN nanorod array through localized surface plasmons

Szu Chi Yang, Pei Kuen Wei, Hui Hsin Hsiao, Pierre Adrien Mante, Yu Ru Huang, I. Ju Chen, Hung Chun Chang, Chi Kuang Sun

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

We report a method that enables the excitation of localized surface plasmons (LSPs) in a gold nanodisk array by placing each nanodisk on top of a GaN nanorod. When the rod length was much longer than the plasmon penetration depth inside the nanorod, the plasmonic field was found to be localized, and coupling between neighboring gold nanodisks was eliminated. The interaction between LSPs and acoustic vibrations in gold nanodisks was then investigated. Owing to the strong localization of the plasmonic field, weak, higher-order vibrational modes of gold nanodisk could be optically observed. Furthermore, such an LSP-based acoustic sensor could be operated at any angle of incident light. Our study not only provides an approach to excite LSPs in high-density metallic arrays, but also opens one of the possible solutions for the development of highly sensitive sub-terahertz hypersonic sensors with high angle tolerance of incident light.

Original languageEnglish
JournalApplied Physics Letters
Volume105
Issue number21
DOIs
Publication statusPublished - Nov 24 2014
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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