Nonlinear refraction in photo-induced anisotropic states of azo-dye containing materials

The optical anisotropic states in the azo-dye Disperse Red 13 doped poly(methyl methacrylate) polymeric film are induced by polarized light and the nonlinear refractive index in these states are studied by the Z-scan technique. It is found that the n₂ of the sample can be controlled by changing both the polarization direction and the intensity of the 514 nm light. Photo-induced isomerization and reorientation of azo chromophores in polymer matrices are used to explain the results.