An optical nanoantenna made of plasmonic chain resonators

We propose a novel structure that behaves like an optical antenna and converts evanescent waves into propagating waves. The system comprises metallic subwavelength cylinders distributed in a dual-period array. It is illuminated by an evanescent wave generated by total internal reflection in a close interface. For particular wavelengths, the system exhibits resonances and the inhomogeneous wave is converted into propagating waves that radiate to the far field. This effect can be controlled by varying the geometrical parameters of the structure, such as the period and the inclination angle. Therefore, the transmitted intensity can be sent to a predesigned direction. This structure could be used in highly sensitive detection devices, among other applications.