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The novel oligomeric thin film structures with photochromic properties were obtained. They based on carbazole-containing oligomer as a matrix and azo-dye 4-((4-nitrophenyl)diazenyl)phenol as a photosensitive additive. Spectral, photoconductive, photovoltaic and information properties of films were investigated. It was shown, that all investigated film composites exhibit photoconductive and photovoltaic properties under light irradiation correspond to the azo-dye absorption region. The features of the photoconductive and photovoltaic properties of the investigated compositions, as well as the possible mechanisms of the photovoltaic effect and charge carriers photogeneration, were discussed. It was shown that the prepared composites can be used as reversible recording media. [ABSTRACT FROM AUTHOR]

In this paper the nonlinear refractive index, n2, of an azo dye (Sudan III) doped nematic liquid crystal was measured at low laser power using closed aperture z-scan and moire deflectometry techniques. The positive sign indicates a self-focusing effect that accrued in the sample. The nonlinear refractive index n2 is in order of 10-6 cm2/W with z-scan method. This observation is found to be in good agreement with the moire deflectometry model. The optical response of the nematic liquid crystals was strongly enhanced by a small amount of dye impurities (Sudan III). Also the effect of external applied AC voltage on the nonlinear refractive is studied. [ABSTRACT FROM AUTHOR]

Photoinduced Anisotropy and All-Optical Poling are the result of two mechanisms, the angularly selective excitation of molecules (Angular Hole Burning) and the rotation of molecules during the excitation–relaxation cycle (Angular redistribution). In this paper we recall some previous results and we present two new experiments. The first one demonstrates the prime importance of reversible photoisomerization for angular redistribution: we compare dichroism and second harmonic generation, with photoisomerizable molecules and non photoisomerizable ones. The second experiment shows an example of the behavior of photoinduced anisotropy, in a liquid crystal azo-polymers: a 3D characterization of anisotropy is necessary. [ABSTRACT FROM AUTHOR]