The phenomenon in which electromagnetic waves, such as light waves, vibrate in a preferred plane or planes; or the process of confining the vibrations to certain planes. In unpolarized light the vibrations are equally distributed in all directions perpendicular to the direction of propagation of the wave. If all the vibrations are confined to one plane, the light is said to be plane-polarized (or linearly polarized). If the light in one plane is out of phase with the light in the plane at right angles to it (i.e. if the peaks and troughs of the waves are not in step), then the light is said to be circularly polarized. If all these phenomena occur together, the light is said to be elliptically polarized. Plane polarization is usually caused by scattering, and circular polarization by strong magnetic fields. Circularly and elliptically polarized light can also be produced by a wave plate. See also stokes parameters.
Subjects: Astronomy and Astrophysics.