Optical Magnetism and Plasmonic Fano Resonances in Metal Insulator-Metal Oligomers

Journal article, 2015

The possibility of achieving:,Optical magnetism at visible- frequencies using plasmonic nanostructures has recently been a,subject of great interest, The,concept is based on designing that support plasmon modes with electron oscillation patterns that imitate current loops, that is, magnetic dipoles. However, the magnetic resonanees are typically spectrally narrow, thereby limiting their applicability in, for example, metamaterial designs. We show that a significantly broader Magnetic response can be,realized in plasmonic pentamers,constructed from metal insulator-metal (MINI) sandwich particles, Each MIM unit acts as 2 magnetic meta atom and the optical magnetism is rendered quasi broadband through hybridization of the in-plane modes. We demonstrate that scattering spectra of individual MIM pentamets exhibit multiple Fano resonances and a broad subradiant spectral window- that signals the magnetic interaction and a hierarchy of coupling effects in these intricate thee-dimensional nanoparticle oligomers.