Photoinduced surface deformations on azobenzene polymer films

Abstract

Laser-induced surface deformation and surface relief grating formation at different intensity levels on azobenzene-functionalized polymer films were investigated. The surface deformation profile induced by a Gaussian laser beam at low intensities reveals strong polarization dependence and establishes that an optical-field component in the direction of the optical-field gradient is essential for this deformation process. A theoretical analysis based on the optical-field gradient force model is presented to account for the deformation behavior at low intensities. In the higher-intensity regime, however, a different mechanism is found to dominate the surface deformation process. Simultaneous formation of two different types of topographic gratings is observed in a two-beam interference experiment. The phase relationship between these surface relief gratings and the interference intensity pattern was deduced based on the results from the single-beam experiments. The erasing behaviors of the two distinct surface relief gratings were experimentally investigated to highlight the two mechanisms involved in these grating recordings.

Statistical Analysis in Homopolymeric Surfaces

“…19a shows the AFM diffraction grating image where alternating irradiated and non-irradiated regions can be observed. Similar surface relief grating formation has been observed in azopolymeric films, in which a driving force that depends on the gradient of the electric field and the local plasticization assisted by the transcis-trans photoisomerization is the mechanisms responsible for the molecular movimentation (Bian et al, 1999;Kumar et al, 1998). However, in the present work, the surface relief grating observed is due to a polymeric chain photo-oxidation, which causes changes in the PPV photo-luminescence, as mentioned before.…”

Light-induced mass transport in amorphous chalcogenides/gold nanoparticles composites

“…2. Amorphous Se (a-Se) and As 20 Se 80 were selected as the film forming compositions. The presence of significant mass-transport in As 20 Se 80 films [15] served as a criterion for its choice; while a-Se film was of interest due to the fact that it is the only ChG composition with the opposite direction of motion of the material (away from light) [16].…”

Optical and Physical Applications of Photocontrollable Materials: Azobenzene-Containing and Liquid Crystalline Polymers

“…The pitch of the fringe included in the structure varied from about 10 μm to a submicron. In addition to the continuous structures, a polarization dependent pit structure has been inscribed using a focused Gaussian beam [119]. The diameter of the pits can vary from a few microns to a few tens of microns.…”