Photoinduced birefringence in an azo-dye-doped polymer

Under varying intensities and polarization of the exciting light, the photoinduced birefringence of azo dye polymer film placed between a pair of orthogonal polarizers is studied by measuring the transmitted intensity. It is concluded that the saturation and stable values of the transmitted intensity are all proportional to the intensity of the exciting light. Both values are also related to the polarization direction of the exciting light, and when the angle 0 between the polarization directions of the probe intensity and the exciting light is lager than 10 degrees, the saturation and stable values of the transmitted light are all proportional to sin(2)2 theta. In addition, the differences in birefringences of the sample were measured accurately by using a compensator and 1.11 x 10(-3) (before excitated) and 3.57 x 10(-3) (after excitated) are obtained.