Nonparallel transition dipole moments and the polarization dependence of electroabsorption in nonoriented conjugated polymers films

Summary form only given. 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, /spl Delta//spl phi/d, between the dominant one-photon and two-photon transition dipole moments responsible for the nonlinear effect. The polarization anisotropy has a maximum value of 3:1 for parallel transition dipole moments, and a minimum value of 1:3 for perpendicular transition dipole moments. We demonstrate that the predicted field-induced absorption anisotropy is consistent with Kleinrnann symmetry for any relative orientation of the dominant transition dipole moments.