Near Field and Optical Diffraction of 3D Dielectric Corner by Transmission Line Modeling and Multipole Expansion of Green's Function

We propose a novel modeling of the dielectric cubic corner, that is suitable for inclusion in a standard electromagnetic (EM) simulator. The model starts from a consideration of the equivalent current densities on the cube facets. It proceeds by employing a classical multipole expansion of the Green's function at the corner and introduces the novel principle of Simultaneous Transverse Resonance Diffraction (STRD) in order to determine the singularity of the EM field. The novel STRD approach considers the analogy between the EM field in proximity of the 90 deg. dielectric corner and resonant transmission lines. We combined the analytical and the numerical approaches in order to obtain an efficient numerical procedure. The theory is validated by standard finite element method (FEM) simulation, yielding information about the accuracy of the near field around the dielectric corner.