Plasmonic behavior of gold nanorod heterodimers with free-electron feed

The plasmon coupling between metal nanostructures can lead to huge local electric field enhancement and new plasmon modes. Here, we study the effect of the close proximity of two gold nanorod particles on the modification of localized surface plasmon (LSP) modes of the individual on gold nanorod in spectral and spatial domain using cathodoluminescence (CL) spectroscopy and imaging in a high resolution scanning electron microscope (SEM). Significantly enhanced resonant emission is observed from the nanorod dimers when the electron beam is injected around the junction between the rods, where the local density of electromagnetic states is raised.