EM Wave Transmission through a Nano-hole in a Plasmonic Layer

We examine the role of the angle of incidence of an incoming EM wave in its transmission through a subwavelength nano-hole in a thin semiconductor plasmonic layer. Fully detailed calculations and results are exhibited for p- and s-polarizations of the incident wave for a variety of incident angles in the near, middle and far zones of the transmitted radiation. Our dyadic Green’s function formulation includes both (1) the electromagnetic field transmitted directly through the 2D plasmonic layer and (2) the radiation emanating from the nano-hole. Interference fringes due to this superposition are explicitly exhibited. Based on an integral equation formulation, this dyadic Green’s function approach does not involve any appeal to metallic boundary conditions. It incorporates the role of the 2D plasmon of the semiconductor layer, which is smeared due to its lateral wave number dependence. We find that the interference fringes, which are clustered near the nano-hole, flatten to a uniform level of transmission directly through the sheet alone at large distances from the nano-hole.