# Brewster angle

The Brewster angle, also known as the polarization angle, is an angle of incidence at which light with a specific polarization is perfectly transmitted through a transparent medium, such as glass or water, without any reflection. The angle is named after Sir David Brewster, a Scottish physicist who first described the phenomenon in the 19th century.

When a beam of light is incident on a boundary between two media, such as air and glass, a portion of the light is reflected back into the first medium, while the rest is transmitted into the second medium. The amount of reflection and transmission depends on the angle of incidence and the polarization of the light.

At the Brewster angle, the reflected light is completely polarized perpendicular to the plane of incidence, while the transmitted light is completely polarized parallel to the plane of incidence. This means that if the incident light is initially unpolarized, the transmitted light will be polarized in a direction perpendicular to the reflected light.

The Brewster angle is given by the equation:

θ_B = arctan(n_2/n_1)

where θ_B is the Brewster angle, n_1 is the refractive index of the first medium, and n_2 is the refractive index of the second medium.

The Brewster angle has many practical applications, such as in the design of anti-glare coatings for lenses and computer screens, and in the measurement of refractive indices of materials. Read more Learning Management System.