Synthesis and Optical Properties of Poly{(4-nitrophenyl)-[3-[N-[2-(methacryloyloxy)ethyl]- carbazolyl]]diazene}

Poly{(4-nitrophenyl)-3-[ N -[2-(methacryloyloxy)ethyl]carbazolyl]]diazene} was prepared and its photoinduced birefringence, diffraction grating, and photorefractive asymmetric two-beam gain coupling were studied. The monomer was obtained by performing azo coupling in a two-phase water−dichloromethane system in the presence of a phase transfer catalyst. Photoinduced birefringence of up to 0.09 was observed and diffraction efficiencies of up to 25% were obtained, with atomic force microscopy studies revealing that the grating profile exhibited a sinusoidal shape. Asymmetric two-beam coupling is observed, indicating photorefractive properties, but the energy transfer phenomena are more complex, involving also diffraction by the photoinduced gratings. The combination of these three optical properties photoinduced birefringence, surface gratings, and two-beam coupling is believed to be unique and may eventually produce an all-optical device built of a single polymer film.