Plasmonic chirality of L-shaped nanostructure composed of two slices with different thickness

Opt Express. 2016 Feb 8;24(3):2307-17. doi: 10.1364/OE.24.002307.

Abstract

A concise method is proposed to fabricate L-shaped Ag nanostructures (LSANs) for generating chirality. Prepared by glancing angle deposition, the LSAN composed of two slices with different thickness is stacked on self-assembled monolayer polystyrene nanosphere arrays by controlling substrate azimuth and deposition time. The strong optical chirality of LSANs is achieved in visible and near-IR regions by measurement. For the circular dichroism spectrum of LSANs, the intensity is enlarged, and its peaks red-shift with increasing thickness difference. When LSANs are stacked on polystyrene spheres of different diameters, enlargement and red-shift are also observed in their circular dichroism spectra with increasing thickness difference. The numerical calculations of finite element method show that the two slices composing LSAN provide cross-electric dipoles and their thickness difference provides phase difference for generating optical chirality. This study not only provides a concise and scalable method for fabricating chiral plasmonic nanostructures but also contributes to understand the knowledge of the mechanism of circular dichroism.

Publication types

  • Research Support, Non-U.S. Gov't