Analytical Ray Tracing for Flat Lenses

An effective technique for the analysis of metasurfaces (MTSs) imposing boundary conditions that exhibit an axially symmetric variation is proposed in this work. It is shown that when the MTS exhibits a radial variability, the ray paths can be found in a very simple form and our technique provides a fast, yet accurate method to evaluate the trajectories of the rays propagating along both isotropic and anisotropic MTSs, either covered or uncovered by a metal plate. This allows for the efficient design of beam-forming devices.