Formation of the patterns of hexagonal symmetry in thin photosensitive films

In this study we analyzed the hexagonal symmetry pattern formation connected with build-up process of the spontaneous gratings (SGs) in AgCl-Ag films irradiated by P-polarized laser beam under conditions of competition between TE-and TM-waveguide modes. The experiments were performed with thin AgCl-Ag films prepared by means of successive deposition in vacuum of the AgCl layer. The films were irradiated with a focused P-polarized beam from He-Ne laser. We judge about an origin and development of SGs using patterns of small-angle scattering (or small-angle diffraction (SAD)). The hexagons arise under condition of a strong competition of the TM0- and TE0-modes with β_TE0≠β_TM0 during formation of SGs. The SAD effect plays an important role in this process.