Brewster angle, θ B
When an unpolarized planar electromagnetic wavefront impinges on a flat dielectric surface, there is a unique angle (θ B), commonly referred to as Brewster angle, at which the reflected waves are all polarized into a single plane.
  1. Expression for Brewster angle:
    θ B = arctan ⁡ n 2 n 1 = arctan ⁡ ( ɛ 2 ɛ 1 ) 1/2
    where n 2 and n 1 are the refractive indices of the receiving surface and the initial medium, respectively, and ɛ 2 and ɛ 1 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 (n = 1.333), glass (n = 1.515), and diamond (n = 2.417), the Brewster angles are 53, 57, and 67.5 degrees, respectively.
PAC, 2007, 79, 293 (Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)) on page 310