Elementary processes of light transformation for slit structures in real and perfect metals

Efficiencies of the elementary transformation processes, transmission, diffraction and surface-plasmon excitation, which occur at the interface with 1D nano-perforated metal, are analyzed. The cases of single slits and periodic arrays of slits as well as the cases of real and perfect metals are considered. The dependences of the found efficiencies on the slit width and on the optical metal permittivity show a number of pronounced peculiarities. The transition to the perfect-metal case with increasing the absolute value of the dielectric optical permittivity em is highly nontrivial. The results obtained are relevant to the description of the extraordinary light transmission through nano-holes in metals. They can serve as a reference point for the treatment of numerous problems of nano-optics of metals. # 2012 Elsevier B.V. All rights reserved.