One-dimensional waveguides induced by photovoltaic dark spatial solitons of partially spatially incoherent light

In LiNbO₃:Fe photorefractive crystal, one-dimensional photovoltaic dark solitons with partially spatially incoherent light beam was observed; and with these solitons, one-dimensional waveguides in the crystal was gotten. Photovoltaic dark solitons resulted from bulk photovoltaic effect when diffraction was exactly balanced by photorefractive self-defocusing. The solitons formation depended on the direction of light beam propagation and the orientation of the beam intensity gradient, with respect to the principal axes of the crystal. In one-dimensional case, the incoherent photovoltaic solitons induced single planar waveguides, which could guide coherent light beam. This experiment proves that the possibility of controlling and switching high-power laser beams with low-power incoherent light sources.