Enhanced optical transmission in a plasmonic nanostructure perforated with compound holes and nanorods

We propose a novel enhanced optical transmission plasmonic nanostructure composed of a metallic film perforated with a compound rectangular hole and nanorod array. The optical characteristics are investigated by the three-dimensional finite-difference time-domain (FDTD) method. An extraordinary enhanced transmission (transmittance over 96%) in the optical regime is obtained as a result of the excitation and hybridization of localized surface plasmon resonances (LSPRs), surface plasmon polaritons (SPPs), as well as the gap plasmon modes supported by the holes. The enhanced optical transmission can be effectively tailored by changing the geometrical parameters such as the length and width of inner cubic Ag nanorods, the gap of rectangular holes, the period of compound hole array, as well as the height of Ag film due to their effects on oscillating charges on metal surfaces. The structure could facilitate numerous important applications in highly integrated plasmonic filters and optoelectronic circuits.