polarization

polarizing filterA polarizing filter has its molecules all aligned in the same direction. Light waves with the same orientation as the filter are absorbed by the molecules' vibrations, thereby reducing the intensity of the light passing through the filter.

polarization, property of certain electromagnetic radiations in which the direction and magnitude of the vibrating electric field are related in a specified way.

Light waves are transverse: that is, the vibrating electric vector associated with each wave is perpendicular to the direction of propagation. A beam of unpolarized light consists of waves moving in the same direction with their electric vectors pointed in random orientations about the axis of propagation. Plane polarized light consists of waves in which the direction of vibration is the same for all waves. In circular polarization the electric vector rotates about the direction of propagation as the wave progresses. Light may be polarized by reflection or by passing it through filters, such as certain crystals, that transmit vibration in one plane but not in others.

The Editors of Encyclopaedia Britannica This article was most recently revised and updated by Erik Gregersen.