Alexei A. KAMSHILIN, Erik RAITA and Timo JAASKELAINEN

University of Joensuu, Department of Physics, Väisälä Laboratory, P.O. Box 111, SF-80101, Joensuu, Finland

(Received May 9, 1996; Accepted July 2, 1996)

A theoretical model considering total internal reflections of fanned beams from the side crystal surfaces and their coupling with the pump beam is proposed. The interaction of these beams results in the light intensity redistribution and in the generation of the photorefractive surface wave. An experimental observation of the light intensity self-concentration near the surface of a thin photorefractive Bi₁₂TiO₂₀ crystal is reported. It results in an acceleration of the photorefractive energy exchange process.

Key words : photorefrection, fanning effect, photorefractive surface wave, sillenite crystals, beam-coupling