  The effect of lattice termination on the surface states in a two-dimensional
truncated photonic crystal slab is experimentally studied in a high index
contrast silicon-on-insulator system. A single-mode silicon strip waveguide
that is separated from the photonic crystal by a trench of variable width is
used to evanescently couple to surface states in the surrounding lattice. It is
demonstrated that the dispersion of the surface states depends strongly on the
specific termination of the lattice.
