## Brewster angle, $$\theta_{B}$$

https://doi.org/10.1351/goldbook.BT07336
When an unpolarized planar electromagnetic wavefront impinges on a flat dielectric surface, there is a unique @A00346@ ($$\theta_{B}$$), commonly referred to as Brewster @A00346@, at which the reflected waves are all polarized into a single plane.
Notes:
1. Expression for Brewster @A00346@: $\theta_{B} = arctan \frac{n_{2}}{n_{1}} = arctan \left (\frac{\varepsilon_{2}}{\varepsilon_{1}} \right)^{1/2}$ 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.
Source:
PAC, 2007, 79, 293. (Glossary of terms used in photochemistry, 3rd edition (IUPAC Recommendations 2006)) on page 310 [Terms] [Paper]