Optics of absorbing planar structures

The considerations of waveguiding are analyzed in isotropic absorbing film systems. In this case all propagation constants become complex numbers and dispersion relation for guided modes differs from the mode equation of the lossless waveguide. The existence of absorption causes measurable shifts of the propagation constants of the free guide modes and ones in the presence of prism coupler. It is shown how the coupling strength is modulated by the absorption of asymmetric slab waveguide.