NONPARALLEL TRANSITION DIPOLE-MOMENTS AND THE POLARIZATION DEPENDENCEOF ELECTROABSORPTION IN NONORIENTED CONJUGATED POLYMER-FILMS

We present a comprehensive analysis of the polarization dependence of the field-induced absorption in nonoriented conjugated polymer films. The results demonstrate that the polarization anisotropy of the field- induced absorption is directly related to the relative angle, Delta ph i(d), between the dominant one-photon and two-photon transition dipole moments responsible for the nonlinear effect. The polarization anisot ropy has a maximum value of 3: 1 for parallel transition dipole moment s, and a minimum value of 1:3 for perpendicular transition dipole mome nts. We demonstrate that the predicted field-induced absorption anisot ropy is consistent with Kleinmann symmetry for any relative orientatio n of the dominant transition dipole moments.