Laser Beam Self-Channeling in a Photorefractive Waveguide Caused by Fanning Effect

We report an experimental observation of the light beam self-channeling inside the photorefractive Bi12TiO20 waveguide-like sample. The phenomenon occurs when the strong fanning effect takes place. Total internal reflections of fanned beams from the waveguide surfaces and their coupling with the pump beam result in the light intensity redistribution inside the photorefractive waveguide. The self-induced channel of the increased light intensity speeds up the photorefractive energy exchange process.