Fano resonances in three-dimensional dual cut-wire pairs

This paper presents an experimental demonstration of pronounced Fano resonances in a remarkably simple, three-dimensional (3D) plasmonic system, composed of two groups of paired cut-wires with different sizes. Theoretical calculations using the Finite Element Method, which are in good agreement with the experiment, are provided to describe the Fano behaviour. The dependence of the Fano line shapes on the separation and offset between the two cut-wire pair units is quantitatively analyzed. The generation of Fano resonances in such nanostructures presents clear advantages over current 3D structures, because of their easier fabrication, and because the optical spectra can be easily and predictably tuned.