title: Observation of surface gap solitons in semi-infinite waveguide arrays.
abstract: We report on the observation of surface gap solitons found to exist at the interface between uniform and periodic dielectric media with defocusing nonlinearity. We demonstrate strong self-trapping at the edge of a LiNbO3 waveguide array and the formation of staggered surface solitons with propagation constant inside the first photonic band gap. We study the crossover between linear repulsion and nonlinear attraction at the surface, revealing the mechanism of nonlinearity-mediated stabilization of the surface gap modes.
authors.affiliation: Nonlinear Physics Centre, Centre for Ultrahigh-Bandwidth Devices for Optical Systems (CUDOS), Research School of Physical Sciences and Engineering, Australian National University, Canberra, Australia.
authors.forename: Christian R
authors.initials: CR
authors.lastname: Rosberg
authors.forename: Dragomir N
authors.initials: DN
authors.lastname: Neshev
authors.forename: Wieslaw
authors.initials: W
authors.lastname: Krolikowski
authors.forename: Arnan
authors.initials: A
authors.lastname: Mitchell
authors.forename: Rodrigo A
authors.initials: RA
authors.lastname: Vicencio
authors.forename: Mario I
authors.initials: MI
authors.lastname: Molina
authors.forename: Yuri S
authors.initials: YS
authors.lastname: Kivshar