Self-trapping of one-dimensional and two-dimensional optical beams and induced waveguides in photorefractive KNbO_3

We demonstrate self-trapping of one-dimensional and two-dimensional optical beams in a photorefractive ${\mathrm{KNbO}}_3$ crystal. We study the waveguides induced by the self-trapped beams for prospective applications of tunable nonlinear frequency conversion in soliton-induced waveguides.