Effects of reorientation of molecules in a nonlinear-optical photoconducting polymer on formation of an antiguide structure

When the poled nonlinear-optical photoconducting polymer is irradiated by the pump light, the generated space charges screen the poling electric field and induce reorientation of the nonlinear-optical molecules. It results in reduction of refractive indices and of a nonlinear-optical coefficient of the polymer. Due to the former reduction, the antiguide structure is so made as to confine the leaky lightwaves. We confirmed the reduction by observing the second-harmonic generation from the pump-irradiated polymer and compared the self enhancement of the Cerenkov-radiation type second-harmonic power generated from a thin-film waveguide. (C) 1998 American Institute of Physics. [S0021-8979(98)05020-8].