Two chiroptical modes of silver nanospirals

Fan Bai, Junhong Deng, Mengsu Yang, Junxue FU, Tsz Fai Jack NG, Jeffery HUANG

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

As an emerging three-dimensional chiral metamaterial, plasmonic nanospirals (NSs) possess inherent chiroptical activity that has attracted increasing attention for developing potential photonic applications. However, the study of chiroptical activity of plasmonic NSs is still in its infancy, especially for NSs made of silver, which is a typical plasmonic material with high plasmonic quality. Herein, we present a systematic study of circular dichroism (CD) of silver NSs (AgNSs) that are fabricated and engineered in helical lengths by glancing-angle deposition (GLAD) and dispersed in ethanol. The CD spectrum is composed of a bisignated mode of two peaks, one in the UV regime and the other in the visible. The UV mode has a resonance wavelength saturating at ∼375 nm and a linewidth decoupled from the helical elongation, while the visible mode tends to have a redshift and its linewidth broadens linearly with the elongation of AgNS. Helical elongation generally amplifies the chiroptical activity of both modes. Finite-element simulation shows good agreement with the experimental CD results, and accounts for the wavelength-related chiroptical distinction in terms of the resonance wavelength. This work contributes to understanding the bisignated chiroptical responses of plasmonic nanospirals, and introduces a simple method to tailor the visible chiroptical activity that is strongly desired to explore a wide range of chirality-related bio-applications.

Original languageEnglish
Article number115703
JournalNanotechnology
Volume27
Issue number11
DOIs
Publication statusPublished - 15 Feb 2016

Scopus Subject Areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering

User-Defined Keywords

  • chiroplasmon
  • chiroptical activity
  • circular dichroism
  • glancing-angle deposition
  • silver nanospirals

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