Abstract
This paper describes the irradiation of AgCl-Ag films, which are prepared by thermal vacuum deposition on glass substrates by nonfocused linearly polarized Gaussian beam of He-Ne laser. The quasiperiodic structures (QPS) are formed under the beam action, these QPS produce anisotropic scattering in both sides from the irradiated spot. The developing of scattering was registered in the direction of light passing through the sample. We showed that instability and turbulence at the QPS formation by Gaussian laser beam have thresholds of exposition. The thresholds are connected with the necessity of QPS development up to the stage, when the interaction between QPS and microgratings, forming QPS and their competition in subsequent growth in developing.