Document Type

Journal Article

Department/Unit

Department of Physics

Title

Two chiroptical modes of silver nanospirals

Language

English

Abstract

© 2016 IOP Publishing Ltd. 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.

Keywords

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

Publication Date

2016

Source Publication Title

Nanotechnology

Volume

27

Issue

11

Start Page

1

End Page

7

Publisher

IOP Publishing

DOI

10.1088/0957-4484/27/11/115703

ISSN (print)

09574484

ISSN (electronic)

13616528

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