Plasmon and periodicity assisted scattering and absorption of light by finite nanowire gratings

Two fundamental effects are known to influence the scattering of light by periodically structured metal scatterers. From the one hand, surface-plasmon resonances are observed for subwavelength noble-metal particles and wires in the mid-infrared and optical bands [1, 2]. Nanosize objects can exhibit resonance behavior at certain frequencies for which the object permittivity is negative. This results in powerful enhancement of scattered and absorbed light that is used in the design of optical antennas and biochemical sensors for advanced applications. In the leading terms, the plasmon resonance wavelength depends on the object shape but not on its dimensions.