Ordinary (unpolarized) light consists of transverse waves whose electric-field vibrations occur in all possible directions perpendicular to the direction of travel. Plane polarized light is light in which these vibrations have been restricted so that they take place in only one plane containing the direction of propagation.
In other words, the electric vector of a plane polarized beam oscillates along a single fixed direction (perpendicular to the direction of travel), rather than in every transverse direction. Such light can be produced by passing ordinary light through a polaroid (or by reflection at the polarizing angle), and its state can be detected using a second polaroid (analyser) which cuts off the light when its axis is crossed with the first. The fact that light can be polarized is direct evidence that light is a transverse wave.
Ordinary (unpolarized) light consists of transverse waves whose electric-field vibrations occur in all possible directions perpendicular to the direction of travel. Plane polarized light is light in which these vibrations have been restricted so that they take place in only one plane containing the direction of propagation.
In other words, the electric vector of a plane polarized beam oscillates along a single fixed direction (perpendicular to the direction of travel), rather than in every transverse direction. Such light can be produced by passing ordinary light through a polaroid (or by reflection at the polarizing angle), and its state can be detected using a second polaroid (analyser) which cuts off the light when its axis is crossed with the first. The fact that light can be polarized is direct evidence that light is a transverse wave.
