Dynamic beam deflection using photorefractive gratings in Bi12SiO20 crystals

Abstract : New configurations for spatial beam steering of a near-infrared laser beam are presented. They are based on the interaction of the beam from a semiconductor laser with a dynamic grating photoinduced in a photorefractive crystal such as Bi12SiO20 (BSO). The demonstrated large values of the deflection angles (120) result from a change in both the grating period and the orientation achieved by optical means. The Bragg condition over this large scan angle is maintained by either recording the grating with a variable wavelength (dye laser) or taking advantage of the spatial nonlinearities of the photorefractive effect. The respective advantages of these two techniques are discussed. Possible application to interconnection between optical fibers for broadband communication is considered.