Abstract

The stability and evolution properties of solitary wave solutions of nonlinear propagation equations are fascinating topics of nonlinear optical dynamics. Two-dimensional (stripe) beams, including solitary wave solutions, are unstable in bulk nonlinear media. The reason is that in bulk media these beams constitute a low-dimensional (1 + 1) subclass of higher-dimensional (2+1) allowable solutions and break up due to transverse instabilities along the “hidden” homogeneous coordinate. We present a spectrum of experimental and theoretical data demonstrating all stages of breakup and subsequent complex spatial evolution of stripe beams for both a focusing and defocusing anisotropic photorefractive nonlinear response. The presented results include transverse modulation instability of a bright solitary stripe (Fig. 1) and snake instability of a dark stripe beam with subsequent formation of vortices or wave front defects[1]. The breakup of wide beams results in the generation of hundreds of spatially turbulent (2+1) filaments[2].

© 1996 IEEE