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.
- 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).
- For a randomly polarized beam incident at Brewster angle, the electric fields of the reflected and refracted waves are perpendicular to each other
- For a wave incident from air on water (), glass (), and diamond (), the Brewster angles are , , and , respectively.
PAC, 2007, 79, 293 (Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)) on page 310