Brewster angle, \(\theta_{\text{B}}\)
When an unpolarized planar electromagnetic wavefront impinges on a flat dielectric surface, there is a unique angle (θB), commonly referred to as Brewster angle, at which the reflected waves are all polarized into a single plane.
  1. Expression for Brewster @A00346@: \[\theta_{\text{B}} = arctan \frac{n_{2}}{n_{1}} = arctan \left (\frac{\varepsilon_{2}}{\varepsilon_{1}} \right)^{1/2}\] where \(n_{2}\) and \(n_{1}\) are the refractive indices of the receiving surface and the initial medium, respectively, and \(\varepsilon_{2}\) and \(\varepsilon_{1}\) are the relative static permittivities (formerly called dielectric constants).
  2. For a randomly polarized beam incident at Brewster @A00346@, 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 @D01671@ (\(n = 2.417\)), the Brewster angles are \(53\), \(57\), and \(67.5\ \text{degrees}\), respectively.
PAC, 2007, 79, 293. 'Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)' on page 310 (