The analysis of TM-mode and TE-mode optical responses of metallic nanostructures by new surface integral equations

摘要

Two sets of new surface integral equations, based on the Stratton-Chu formulation, are developed to analyze the interactions of an incident electromagnetic wave with a 2D metallic nanostructure for the transverse-magnetic (TM) mode and the transverse-electric (TE) mode, respectively. For the former, the surface integral equations are in terms of the surface components of the tangential magnetic field H{sub}z, the normal displacement field D{sub}n, and the tangential electric field E{sub}t. As to the latter, the equations are in terms of the surface components of the tangential electric field E{sub}z, the normal magnetic flux density B{sub}n, and the tangential magnetic field H{sub}t. The numerical results show that for TM mode a standing wave pattern is observed on the backside of a metallic nanoscatterer with a size of several hundreds nanometers, which is caused by two surface plasmon waves creeping along the boundary clockwise and counterclockwise. However there is only a shadow zone on the backside of the metallic scatterer for TE mode.