Photo-induced non-linear susceptibility patterns in electro-optic polymers

We present microscopic scale photo-induced non-linear susceptibility patterns in organic materials. This patterns are observed by reflection second harmonic generation microscopy and atomic force microscopy. The characteristics of the non-linear susceptibility tensor are engineered during the active film preparation. Several techniques have been used to pattern the non-linear response: re-alignment through a chrome mask of previously electrically poled samples, Lloyd-mirror interferometric configuration to imprint any desired susceptibility periodicity in the sample and all optical poling using mutually coherent beams from a frequency-doubled picosecond Nd:Yag laser. Images of different scanned patterns are shown, direct evidence of periodic structures, two-dimensional patterns and applications to 2D photonic crystals are discussed.