Surface vortex solitons

We discover the existence of vortex solitons supported by the surface between two optical lattices imprinted in Kerr-type nonlinear media. Such solitons can feature strongly noncanonical profiles, and we found that their properties are dictated by the location of the vortex core relative to the surface. The refractive index modulation forming the lattices at both sides of the interface results in complete stability of the vortex solitons in wide domains of their existence, thus introducing the first known example of stable topological solitons supported by a surface.