title: Giant optical activity from the radiative electromagnetic interactions in plasmonic nanoantennas.
abstract: We fabricate the linear chains of twisted gold nanorods by a facile chiral molecular templating method. In such a chiral plasmonic system, particle-particle separation distances are in the order of the light wavelength and are much larger than the sizes of individual particles. As a result, the inter-particle interactions in this chiral system are mediated mainly by a relatively weak far-field plasmonic coupling, rather than a strong near-field coupling. However, such a chiral system of twisted gold nanorods show a huge surface plasmon based circular dichroism response, with the highest anisotropy factor around 0.027. This is in contrast to the previous studies in which near-field plasmonic coupling is an indispensable prerequisite to obtain strong optical activity from a chiral plasmonic nanostructure. Our study demonstrates here an alternative strategy for achieving huge chiroptical response of a chiral plasmonic nanostructure based on far-field, radiative electromagnetic interactions of metallic nanoparticles. Theoretical simulations show a satisfactory agreement with the experimental results. This study may provide more flexible ways to design chiral plasmon nanostructures with strong CD responses for various applications.
authors.affiliation: School of Physics, Key Laboratory of Cluster Science of Ministry of Education, Beijing Institute of Technology, Beijing, 100081, P R China.
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.forename: Rongyao
authors.initials: R
authors.lastname: Wang
authors.forename: Yinglu
authors.initials: Y
authors.lastname: Ji
authors.forename: Dawei
authors.initials: D
authors.lastname: Zhai
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Wu
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
authors.forename: Keqiu
authors.initials: K
authors.lastname: Chen
authors.forename: Hongxing
authors.initials: H
authors.lastname: Xu