Brewster’s angle

Definition

Brewster's angle is the angle of incidence at which light with a particular polarization is perfectly transmitted through a transparent dielectric surface without any reflection. It occurs when the refracted and reflected light rays are perpendicular to each other.

5 Must Know Facts For Your Next Test

1. At Brewster's angle, the reflected light is completely polarized parallel to the incident surface.
2. The formula for Brewster's angle is $\theta_B = \tan^{-1} \left( \frac{n_2}{n_1} \right)$, where $n_1$ and $n_2$ are the refractive indices of the two media.
3. Brewster's angle depends on the wavelength of the light because different wavelengths have different refractive indices.
4. When unpolarized light hits a surface at Brewster's angle, only light polarized perpendicular to the plane of incidence will be refracted.
5. Brewster's angle is also known as the polarization angle.

Review Questions

Related terms

Polarization:

The orientation of oscillations in the plane perpendicular to a wave’s direction of travel.

Refractive Index:

A measure of how much a ray of light bends when it enters that material.

Snell's Law:

$n_1 \sin(\theta_1) = n_2 \sin(\theta_2)$; it describes how waves change direction when they pass from one medium into another.