Extraordinary Optical Transmission in Metallic Nanostructures with a Plasmonic Nanohole Array of Two Connected Slot Antennas

A novel subwavelength transparent metal structure consisting of a periodic connected slot antennas nanohole array in a gold film is proposed in this work. The transmission characteristics of the structure are investigated by the three-dimensional finite-difference time-domain (3D FDTD) method. A broad transmission band with bandwidth more than 300 nm and maximum transmission intensity more than 90 % is achieved via the localized surface plasmons at the edges of nanoholes, the surface plasmon polaritons (SPPs) on the surface of the gold film, and Fabry–Férot resonances of surface plasmons in the nanoholes. The transmission properties can be tailored by changing the geometrical parameters and dielectric materials filled in the holes. These results indicate that our structure has potential applications in optical devices such as plasmonic filters, sensors, and so on.