Fig. 1. (a) Experimental setup for observing RWs; the blue square is used to observe the spectrum of the lattice. BS, beam splitter; AM, amplitude mask; HVPS, high-voltage power supply. (b) Probe light at the front plate of SBN crystal. (c) The induced lattice beams in SBN crystal. (d) The Brillouin zone of the lattice.

Fig. 2. The output patterns of the probe beam in the lattice in (a) linear and (b) nonlinear situations in the experiment. U = 800 V.

Fig. 3. The experimental results of the PDF for AI in an optical lattice (blue circles) and in a homogeneous medium (red triangles) under a nonlinear condition, and in an optical lattice under a linear condition (black squares). U = 800 V.

Fig. 4. The spectra of the probe beam in (a), (c) an optical lattice and (b), (d) a homogeneous medium under linear and nonlinear conditions, respectively. U = 800 V.

Fig. 5. The propagation of probe beam in (a) an optical lattice and (b) a homogeneous medium in numerical simulation. κ = 2.

Fig. 6. The PDF of AI in optical lattice (blue circles), in homogeneous medium (red triangles) under a nonlinear condition, and in optical lattice under a linear condition (black squares) in numerical simulation. κ = 2.