Observation of two-dimensional lattice interface solitons
  We report on the experimental observation of two-dimensional solitons at the interface between square and hexagonal waveguide arrays. In addition to the different symmetry of the lattices, the influence of a varying refractive index modulation depth is investigated. Such variation strongly affects the properties of surface solitons residing at different sides of the interface. 
A. Szameit, Y. V. Kartashov, F. Dreisow, M. Heinrich, V. A. Vysloukh,   T. Pertsch, S. Nolte, A. Tunnermann, F. Lederer, L. ...