Hybridized plasmon resonant modes in molecular metallodielectric quad-triangles nanoantenna

In this study, we examined the plasmon response for both metallic and metallodielectric nanoantennas composed of four gold (Au) triangles in a quadrumer orientation. Tailoring an artificial metallic quadtriangles nanoantenna, it is shown that the structure is able to support pronounced plasmon and Fano resonances in the visible spectrum. Using plasmon transmutation effect, we showed that the plasmonic response of the proposed cluster can be enhanced with the placement of carbon nanoparticles in the offset gaps between the proximal triangles. It is verified that this structural modification gives rise to formation of new collective magnetic antibonding (dark) plasmon modes. Excitation of these subradiant dark modes leads to formation of narrower and deeper Fano resonances in the spectral response of the metallodielectric nanoantenna. To investigate the practical applications of the metallodielectric structure, we immersed the nano-assembly in various liquids with different refractive indices to define its sensitivity to the environmental perturbation as a plasmonic biological sensor. (C) 2015 Elsevier B.V. All rights reserved.