Although coherent light is usually required for the self-organization of regular spatial patterns from optical beams, we show that peculiar light matter interaction can break this evidence. In the traditional method to record laser-induced periodic surface structures, a light intensity distribution is produced at the surface of a polymer film by an interference between two coherent optical beams. We report on the self-organization followed by propagation of a surface relief pattern. It is induced in a polymer film by using a low-power and small-size coherent beam assisted by a high-power and large-size incoherent and unpolarized beam. We demonstrate that we can obtain large size and well organized patterns starting from a dissipative interaction. Our experiments open new directions to improve optical processing systems. We also discuss the relevance of our experiment to other systems such as social insects, for which a self-assembly or spatial pattern is organized within a collective group, starting from amplified fluctuations.
The holographic optical storage capacity with photopolymer is improved by creating a multigrating onto the surface of a azopolymer thin film with the use of a liquid droplet. We show by this method that three kinds of gratings can be created and controlled by different laser beam parameters as polarization or incident angle.
The orientation and attachment of neuronal cells were controlled by submicron-scale topographical patterns. The surface structure is realized with a laser beam and photo-responsive azobenzene polymer thin films. A surface relief grating (SRG) can be produced by self-organization of molecules under the action of light. The cells are attached onto the SRG and preferentially grown along the groove direction. The use of polymer thin films is good candidate for cellular engineering applications.