Photoinduced surface deformations on azobenzene polymer films

• Published in: Journal of applied physics 1999-10, Vol.86 (8), p.4498-4508
• Main Authors: Bian, Shaoping, Williams, John M., Kim, Dong Yu, Li, Lian, Balasubramanian, Srinivasan, Kumar, Jayant, Tripathy, Sukant
• Format: Article
• Language: English
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.371393

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.