General laws of reflection and refraction for metasurface with phase discontinuity

The general reflection and refraction laws at the metasurface with an abrupt phase shift are derived by two methods based on Fermat's principle and the boundary conditions of continuity, it is found that one or two critical angles for total internal reflection exist not only when a light beam impinges on the optical sparse material from the optical denser material, but also when a light beam spreads from the optical sparse material to the optical denser material. Anomalous reflection and refraction, such as, negative reflection and negative refraction may occur when a light beam passes through the metasurface, and the conditions of their occurrence are given. Finally, a kind of metasurface based on one-dimensional phase mask is designed to control the light propagation.