Open AccessStrong circular dichroism enhancement by plasmonic coupling between graphene and h-shaped chiral nanostructure
Author(s) -
Yongkai Wang,
Jun Dong,
Zhongyu Wang,
Shangqi Zhou,
Qijing Wang,
Qingyan Han,
Wei Gao,
Kaili Ren,
Jianxia Qi
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.033869
Subject(s) - circular dichroism , circular polarization , plasmon , graphene , absorption (acoustics) , materials science , absorbance , polarization (electrochemistry) , nanostructure , optics , optoelectronics , chirality (physics) , metamaterial , physics , molecular physics , nanotechnology , symmetry breaking , chiral symmetry breaking , chemistry , crystallography , quantum mechanics , nambu–jona lasinio model , microstrip
Circular dichroism (CD) is useful in polarization conversion, negative refraction chemical analysis, and bio-sensing. To achieve strong CD signals, researchers constantly break the symmetry of nanostructures. However, how to further enhance the CD based on a new mechanism has become a new challenge in this field. In this work, a hybrid plasmonic chiral system composed of an array of graphene ribbons (GRs) over h-shaped sliver chiral nanostructures (HSCNs) is theoretically investigated. Results demonstrate that the plasmonic coupling between HSCNs and GRs results in different enhanced absorptions for different circularly polarized lights. The absorbance of right circularly polarized light is enhanced to perfect absorption; the absorption of left circularly polarized light is enhanced weakly. It leads to the CD effect of HSCNs@GRs approaching 88%. The loss distributions of HSCNs and HSCNs@GRs reveal that the absorption is enhanced and transferred from HSCNs to GRs. Moreover, the current distributions of HSCNs@GRs are simplified to equivalent LC resonant circuits, which can qualitatively explain the change of CD signals by tuning geometrical parameters of HSCNs@GRs. The findings of this work provide a new method of enhancing chirality and benefit the design of graphene-based chiral optoelectronic devices.