Dichroism in a plasmonic lattice based on triskelion nanoelements

Abstract

Dichroism is the different optical response obtained for left or right circular polarised light and characteristically occurs in chiral systems. This work is focused on enhancing the dichroism observed in the plasmonic response of Au planar nanoelements (triskelion) showing helicity. Numerical simulations have been performed to study the electromagnetic response of these systems. First, a free-standing triskelion has been studied to obtain its natural response. Then, a triskelion on a silica substrate and two stacked free-standing triskelia have been considered so as to observe the response of 3-dimensional true chiral structures. Finally, a hexagonal array of the triskelion stack has been tested to analyse the hybridisation of localised and collective modes.