Formation of Enhanced Uniform Chiral Fields in Symmetric Dimer Nanostructures
Artikel i vetenskaplig tidskrift, 2015

Chiral fields with large optical chirality are very important in chiral molecules analysis, sensing and other measurements. Plasmonic nanostructures have been proposed to realize such super chiral fields for enhancing weak chiral signals. However, most of them cannot provide uniform chiral near-fields close to the structures, which makes these nanostructures not so efficient for applications. Plasmonic helical nanostructures and blocked squares have been proved to provide uniform chiral near-fields, but structure fabrication is a challenge. In this paper, we show that very simple plasmonic dimer structures can provide uniform chiral fields in the gaps with large enhancement of both near electric fields and chiral fields under linearly polarized light illumination with polarization off the dimer axis at dipole resonance. An analytical dipole model is utilized to explain this behavior theoretically. 30 times of volume averaged chiral field enhancement is gotten in the whole gap. Chiral fields with opposite handedness can be obtained simply by changing the polarization to the other side of the dimer axis. It is especially useful in Raman optical activity measurement and chiral sensing of small quantity of chiral molecule.

Photonic

Optical-Activity

Metamaterial

Lithography

Plasmonic Nanostructures

Molecules

Oligomers

Nanocrystals

Nanowires

Circular-Dichroism

Resonances

Författare

X. R. Tian

Shandong Normal University

Yurui Fang

Chalmers, Teknisk fysik, Bionanofotonik

M. T. Sun

Institute of Physics Chinese Academy of Sciences

Scientific Reports

2045-2322 (ISSN)

Vol. 5 Article no. 17534- 17534

Ämneskategorier

Annan teknik

DOI

10.1038/srep17534