Interference of laser beam in thin film on plane-parallel dielectric substrate at Rayleigh scattering

Thin films on plane-parallel dielectric substrates represent waveguide or quasi-waveguide samples. The nonlinear formation effect in a periodic structure (PS) connected with the excitation of waveguide modes in the film due to initial Rayleigh scattering is known. In the present paper, it is shown that the role of Rayleigh scattering of light in the sample is much broader-the formation of periodic structures far outside the acting laser beam due to nonlinear effects of photoinduced change accumulation in the film is revealed. AgCl-Ag films (h_AgCl ≈ 100 nm, h_Ag ≈ 10 nm) evaporated in vacuum on plane-parallel glass substrates with thickness H = 1.35 mm were used in the experiment.