Engineering Physics

14.15 Polarization by reflection

In 1809, Malus, a French scientist discovered that when ordinary light in incident on the surface of a transparent medium like glass or water, then light can be partially or completely polarized on reflection. The extent of polarization of reflected light varies with the angle of incidence. In 1811, Sir David Brewster noticed the extent of variation polarization of reflected light by varying the angle of incidence on the surfaces of different transparent materials. He observed that for a particular angle of incidence [θ_i = θ_p, θ_p = angle of polarization] the reflected light is completely plane polarized as shown in Fig. 14.23. This angle of incidence is known as Brewster’s angle or angle of polarization. The angle ...