Circular dichroism enhancement in grapheme with planar metal nanostructures: A computational study

Abstract

Circular dichroism (CD) is widely used in bio-sensing, chemical analysis, and negative refraction. However, a concise method is required to enhance CD in planar chiral plasmonic nanostructures. In this work, graphene ribbons (GRs) are introduced in planar h-shaped-metal chiral nanostructures (PHCNs) to enhance CD. Calculated results show that the absorption spectra of PHCNs are differently enhanced because of the plasmonic coupling between PHCNs and GRs under different circularly polarized lights, thereby leading to CD enhancement. The loss distributions of PHCNs@GRs reveal that the loss is transferred from PHCNs to GRs. The current distributions of PHCNs@GRs are regarded as equivalent LC resonant circuits to explain the shift of the CD spectra by tuning the geometrical parameters of PHCNs@GRs. The results help design graphene-based chiral plasmonic nanostructures.