Question

Two identical imperfect polarizers are placed in the way of a natural beam of light. When the polarizers' planes are parallel, the system transmits η = 10.0 times more light than in the case of crossed planes. Find the degree of polarization of light produced

(a) by each polarizer separately;

(b) by the whole system when the planes of the polarizers are parallel.

Answer 1

Let us represent the natural light as a sum of two mutually perpendicular components, both with intensity I0 . Suppose that each polarizer transmits a fraction α1 of the light with oscillation plane parallel to the prinicipal direction of the polarizer and a fraction α2 with oscillation plane perpendicular to the principal direction of the polaizer. Then the intensity of light transmitted through the two polarizers is equal to

(a) Now the degree of polarization produced by either polarizer when used singly is

(b) When both polarizer are used with their principal directions parallel, the transmitted light, when analysed, has