Oriented conjugated polymer thin films for all optical switching applications

Obtaining of thin ordered films from several pi electron conjugated systems, such as poly(3-alkyl thiophenes) (PAT), polyaniline (PANI), polyparaphenylene (PPV) and from a sexithiophene oligomer (6-T) is described and discussed. Three thin film fabrication techniques: spinning, drawing and vacuum evaporation are used and compared. The spinning technique gives good optical quality thin film with an "in plane" order. The polymer chains align preferably parallel to the substrate plane. The drawing technique leads also to a partial orientation of thin films with polymer chains preferably oriented either in the drawing direction or perpendicular to it, depending on concentration and the drawing speed. The degree of order is studied by the linear dichroism technique and the optical birefringence. In the case of sufficiently good optical quality the thin film refractive indices, their anisotropy and dispersion were determined by the m-lines techniques. The nonlinear optical properties of thin films were measured by the optical third-harmonic generation.