Surface Plasmon Polariton Mediated Coupling of Cavity Modes in Nanostructured Slit Arrays Analyzed by Electron Energy Loss Spectroscopy in a Transmission Electron Microscope

Surface plasmon polaritons supported by the walls of rectangular slits in a thin Au film hybridize with resonant cavity modes in the slits. The coupling of the hybridized surface plasmon polariton cavity modes in slit arrays with respect to varying the slit size, inter-slit distance and number of slits was analyzed by electron energy loss spectroscopy in a transmission electron microscope. Strong next-neighbor coupling as well as mode splitting dependent on the inter-slit distance was observed.