No abstract

Light induced waveguides produced by lateral illumination of a photorefractive crystal show a complex dynamic evolution upon removal of the sustaining applied electric field. Using this effect, deflection and modulation of the guided light is realized by taking advantage of the screening and counter-screening of the space charge distribution. The spot separation upon deflection can exceed 10 times the original waveguide width. Numerical simulations of the refractive index evolution and beam propagation show a good agreement with the observations.

Photoinduced waveguides are generated by lateral illumination of photorefractive strontium barium niobate. The light-induced waveguides show a complex dynamic relaxation upon removal of the sustaining voltage, which can be exploited for deflecting or modulating the guided wave. The deflection distance easily exceeds 100 µm in a 1 cm long crystal. The observed dynamics agrees with the predictions of numerical calculations of the beam propagation under the appropriate relaxation of the refractive index distribution. We also present a novel method to confine in the second transverse direction the otherwise intrinsically one-dimensional photoinduced waveguides. Dynamic channel waveguides in the bulk of the material are demonstrated in this way.