The phenomenon of polarization by reflection is used in the construction of pile of plates. It consists of a number of glass plates placed one over the other as shown in Figure in a tube of suitable size. The plates are inclined at an angle of 32.50 to the axis of the tube. A beam of monochromatic light is allowed to fall on the pile of plates along the axis of the tube. So, the angle of incidence will be 57.50 which is the polarizing angle for glass.
Fig: Pile of plates
The vibrations perpendicular to the plane of incidence are reflected at each surface and those parallel to it are transmitted. The larger the number of surfaces, the greater is the intensity of the reflected plane polarized light. The pile of plates is used as a polarizer and an analyzer.