Numerical study of TE-wave propagation in waveguides with graded plasmonic obstacles

We study transmission, reflection and absorption phenomena in a hollow waveguide of arbitrary cross section, with an inserted graded dielectric layer and TE-wave propagation. We compare the numerical results for the power transmission, reflection and absorption coefficients, obtained using the software COMSOL Multiphysics, with the corresponding results obtained using exact analytic formulae. The results of the present numerical study indicate an excellent agreement with the corresponding exact analytical results. The method proposed in this paper gives directly applicable results that do not require cascading and mode-matching. At the same time, our method has the advantage of being able to model smooth material transitions, that are more realistic in several applications.