Study of Localized Surface Plasmon properties on metallic nano-rods towards optical antennas

Localized Surface Plasmon (LSP) characteristics of the metallic nano-rod, the promising candidate for the optical nanoantenna, are investigated. Geometrical parameters including size, number, and gap dimensions of the nano-rods clearly affect the optical field enhancement and evanescent electric field distribution. The hollow nano-rod exhibits higher field enhancement compared to that of other rod geometries and the maximum electric field is found at the so called, resonant wavelength. As the number of solid nano-rods increases, the optical field of the first order decreases. It is found that the coupling fields in the gaps between solid nano-rods can be optimized to obtain desirable radiation patterns.