Numerical Analysis of Thin Transparent Film Influence on Reflecting and Absorbing Properties of Metallic Mirror

The problem of plane electromagnetic wave interaction with a planar structure comprising a metallic mirror coated by a thin transparent dielectric film is analysed by the method of single expression (MSE). The normal incidence of wave on the structure from the side of the dielectric film is considered. Oscillating behaviours of the reflectance and the absorptance of the structure depending on the wavelength-scale dielectric layer are obtained. At the maximums of the reflectance the minimums of the absorptance and vice versa are observed. At some thickness of the dielectric layer the reflectance of the structure is higher than the reflectance of the uncoated metallic mirror. The corresponding distributions of electric field amplitude along the structure at maximal and minimal reflectance are presented. The structure comprising a metallic mirror coated by a thin transparent film can be used as a resonant absorber or highly reflecting mirror with minimal absorption