Analyzing lateral X(2)-distributions of poled nonlinear optical polymer films

Electric field poling of nonlinear optical (NLO) polymer films at very high electric fields can lead to chi((2))-distributions with poor spatial homogeneity, making such films unsuitable for optical devices. We report on further improvements of our scanning second harmonic microscopy using scanning near field optic techniques and on results on scanning optically poled films. Using a scanning Kelvin microprobe, a two-dimensional image of the charge and polarization distribution inside the polymer films can be obtained. Similarities between the charge image and the second harmonic image are observed and allow to analyze the cause of the chi((2))-fluctuations. By measuring poling currents through triple stack layers and simultaneously detecting the second harmonic response, the internal electric field inside the NLO-film can be determined. Amorphous SiC:H layers, which were obtained by plasma enhanced chemical vapor deposition (PECVD), are shown to be suitable for optical buffer layers and for dielectric interface coatings.