POLARIZATION OF LIGHT

Light emitted by an excited atom is polarized, i.e. the oscillating electric field lies on the same plane along the direction of propagation. Polarization of light is a good indicator that light as a wave is transverse.

 A light source (e.g. a fluorescent lamp) consists of many excited atoms emitting light independently. The light therefore consists of many independent waves that are randomly polarized about the direction of propagation. Such light is said to be un-polarized.

The diagram above shows an un-polarized light directed out of the page. It is made up of waves with randomly directed electric fields. Each electric field can be resolved into two perpendicular components.