Surface relief gratings and complex structures observed in elastomer azo-dye systems

In this paper a preliminary investigation of thin films of polymer (elastomer) and azo dye for holographic recording is presented. The analyses of recorded structures on the surface of dye elastomer thin film after irradiation with several spatial light configurations is reported. Measurements with atomic force microscope (AFM) evidence the presence of complex structures for profiles modulation in both directions, perpendicular and parallel to the grating wave vector. It is concluded that the formation of complex structures, during the holographic recording, could be attributed to the combination of an effect of spontaneous patterning resulting from light induced surface instability, and the usual massive material displacement effect observed during the surface relief gratings (SRG) formation in polymer-dye systems.