Ekpekpo, A., Iyayi, S. E., Aiyohihum, E.
In a thin dielectric, semiconductor or metal film in the regions or indentation there exist local "Plasmon" resonances of small radius 'tn << L, where L is the "horizontal" size of the roughness. Main characteristics of these resonances (frequencies and widths) are discussed as dependent on the roughness and on the degree of the film indentation when the dependence of the dielectric constant of the film on the electric field strength (e= eo(w) + aE2) in the region of the "Plasmon" resonance (i.e. at | eo(w)| << I) is taken into account, it leads to the appearance of new ("non-linear"} local resonances, The conditions of the appearance of such resonances, specially, the region of their localization, differ from analogous conditions for linear resonances.
