Anomalous absorption of electromagnetic waves in a layered structure with complex permittivities

It is shown theoretically that the absorptivity of bulk TE and TM electroma gnetic waves by a thin layer with large complex dielectric permittivity has a strong (as much as 100%) maximum at an optimal layer thickness that is u sually much smaller than the wavelength and the wave penetration depth (ski n-depth) in the layer. The analysis is carried out in the frictional contac t approximation, in which the layer can be replaced by a contact of the sur rounding media with special boundary conditions that are analogous to the c onditions at a contact with linear mechanical friction. The effects of a no n-zero real part of the layer permittivity, and non-zero dissipation in the surrounding media on the anomalous absorption are investigated theoretical ly in detail. Simple analytical equations for the absorptivity maximum, opt imal layer thickness and optimal incidence angles are derived and analysed. Differences in the anomalous absorption of TE and TM waves in layered stru ctures with complex permittivities are described and explained from the phy sical point of view. (C) 1999 Published by Elsevier Science B.V. All rights reserved.