Gaussian beams for quasi-optical-systems: Modeling dichroic surfaces near a zero of transmission or reflection

Gaussian-beam based methods are well-known for modeling quasi-optical systems constituted by mirrors, lenses, and horn antennas. In this article, a solution is proposed to include dichroic surfaces while maintaining the Gaussian-beam formulation. Special attention is devoted to the case where the dichroic surface response presents a zero near the angle of incidence. Numerical experiments are led on a dielectric slab to show the efficiency of the method.