Electro-optic characterization of two novel organic materials in thin polymeric films

The linear electro-optic coefficients (Pockels coefficients) of two novel organic chromophores, doped in thin films of poly(methyl methacrylate) (PMMA), are determined through a simple experimental method based on a waveguide sample geometry. A DC electric field is applied onto each polymeric film inducing birefringence. This varies the polarization state of a laser beam passing through the film. Measuring these variations, the electro-optic coefficients can be determined for different values of the applied electric field. The microscopic molecular parameters, dipole moment μ and first order hyperpolarizability β are calculated. The results indicate that the existence of ionic bonds at the edge of the molecule of a chromophore increases its dipole moment, while the presence of strong acceptors enhances its first order hyperpolarizability.