Observation of surface dark solitons in nonlocal nonlinear media.

We investigated surface dark solitons (SDSs) at the interface between a self-defocusing nonlocal nonlinear medium and a linear medium, both theoretically and experimentally. We demonstrate that fundamental and higher-order SDSs can exist when the linear refractive index of the self-defocusing medium is much greater than that of the linear medium. The fundamental and second-order solitons are observed at the interface between air and a weakly absorbing liquid.