Wave-particle duality and tunable steering of solitons in Kerr media

A frequently addressed problem in the study of spatial solitons is the dynamics of the beam at the interfaces between linear-nonlinear or nonlinear-nonlinear media (Aceves et al., 1989). In the highly nonlocal case, it has been shown that spatial solitons are robust enough to survive the transition and can either pass the interface without any changes or be totally internally reflected (Peccianti et al., 2006). The trajectory can also be controlled by the power of the soliton (Alberucci and Assanto 2010). Such features enable us in using solitons for all-optical computation. We study the dynamics of solitons launched in a medium with a modulated linear refractive index. Such modulations can give rise to interesting behavior in the propagation properties of the solitons. We observe that the optical soliton undergoes a transition from a wave-like to a particle-like behavior depending on the ratio between its width and the width of the defect, i.e. upon the power of the soliton.