Radial breathing modes coupling in plasmonic molecules

Abstract

Metallic hexamer, very much the plasmonic analog of benzene molecule, provides an ideal platform to mimic modes coupling and hybridization in molecular systems. To demonstrate this, we present a detailed study on radial breathing mode (RBM) coupling in a plasmonic dual-hexamers. We excite RBMs of hexamers by symmetrically matching the polarization state of the illumination with the distribution of electric dipole moments of the dual-hexamer. It is found that the RBM coupling exhibits a nonexponential decay when the inter-hexamer separation is increased, owing to the dark mode nature of RBM. When the outer hexamer is subjected to the in-plane twisting, resonant wavelengths of two coupled RBMs..