Deep UV light induced, fast reconfigurable and fixed waveguides in Mg doped LiTaO(3)

Dynamic waveguides are induced beneath the surface of magnesium doped near-stoichiometric lithium tantalate by deep UV light at lambda = 257 nm using the interband photorefractive effect. The waveguides can be reconfigured in 10 ms at UV intensities of 100 mW/cm(2). We show the importance of the background illumination for the build-up of dynamic optical waveguides. We also present a new fixing process of the light-induced waveguide structures when the background light is absent. These quasi-fixed structures with dark decay times of several days are due to charges trapped in deep traps.