A study on transmitted intensity of disturbance for air-spaced Glan-type   polarizing prisms
  We study theoretically and experimentally the transmission intensity of polarized light through the air-spaced Glan-type polarizing prsims. It is found that the variation of the transmitted intensity with the rotation angle deviates from Malus Law, exhibiting a cyclic fluctuation with the rotation angle. The occurrence of the disturbance is explained by the use of an argument based on the interference effect produced from the air-gap in the prisms. The theoretcal results are well agreed with the experimental ones. By selecting the proper cut angle of prism and reducing the thickness of air-gap in prism, the disturbance may be minimized. 
Ji-Yang Fan, Hong-Xia Li, Fu-Quan Wu