Light is a form of energy. It has many properties. In some cases, light behaves like a flux of particles, and in some cases like waves. Thatswhy wave-particle dual nature assigned to light. Rectilinear propagation of light, reflection and refraction hints at particle nature whereas interference, diffraction etc. leads to wave nature. If we assume wave nature, there can be two types-longitudinal and transverse. Polarization phenomenon of light establish transverse nature of light. Polarized light can be produced by reflection, refraction (pile of plates), scattering, selection absorption and double refraction. Calcite and quarts are doubly refracting materials. Both refracted rays seems to be polarized. Nicol prism, a device fabricated from calcite crystal is used as polarizer and analyzer. Half wave plates and quarter wave plates are effectively used to produce plane polarized light, elliptically polarized light and circularly polarized light. some materials rotate the plane of polarization of light. They are called optically active materials. Quartz, sugar crystals, tartaric acid, sugar solution are examples. Polarimeter is a device used to determine the angle(amount) of polarization.