2D interaction of a Gaussian Beam with a dichroic surface for the modeling of quasi-optical systems

One solution to model quasi-optical system - systems generally constituted by elements of large dimension with respect to the wavelength - is to use asymptotics, such as Gaussian Beams (GB) based techniques [1]. In these systems, dichroic surfaces are used to split, filter or mix an input signal. However, these surfaces are generally made of periodic elements of size that does not exceed a fraction of wavelength. Therefore, they cannot be modeled by such methods. In this paper we propose a technique, based on a spectral representation, to treat the interaction of a GB with a dichroic surface, we suppose that the fields reflected and transmitted by the interface can be approximated by GBs.