Nonlinear anisotropic scattering of laser beam in photosensitive thin AS/sub 2/S/sub 3/-Ag films

The photosensitivity of thin As/sub 2/S/sub 3/-Ag films has been known for a long time. However, the nonlinear optical effects developing in these films at large expositions is poorly investigated. The present work is about the inducing of periodical structures (PS) connected with the excitation of waveguide TE- and TM-modes in the film by a focused linearly-polarized Gaussian laser beam. The origin and development of scattering light bands (SLBs) is an external sign of the PS formation. SLBs represent an example of a spatio-temporal transformation of the laser beam in a nonlinear medium.