We analyze localization of light at the interface separating square and hexagonal photonic lattices, as recently realized experimentally in two-dimensional laser-written waveguide arrays in silica glass with self-focusing nonlinearity [A. Szameit { \em et al.}, Opt. Lett. { \bf 33}, 663 (2008)]. We reveal the conditions for the existence of { \em linear} and { \em nonlinear} surface states substantially influenced by the lattice topology, and study the effect of the different symmetries and couplings on the stability of two-dimensional interface solitons.
Categories: nlin.PS