When an unpolarized planar electromagnetic wavefront impinges on a flat dielectric surface, there is a unique angle (), commonly referred to as Brewster angle , at which the reflected waves are all polarized into a single plane. Notes: 1. Expression for Brewster angle : where and are the refractive indices of the receiving surface and the initial medium, respectively, and and are the relative static permittivities (formerly called dielectric constants). 2. For a randomly polarized beam incident at Brewster angle, the electric fields of the reflected and refracted waves are perpendicular to each other 3. For a wave incident from air on water ( ), glass ( ), and diamond ( ), the Brewster angles are , , and , respectively.