Photorefractive lattice surface waves with diffusion nonlinearity

摘要

We introduce what we believe to be a new type of nonlinear surface wave, photorefractive lattice surface wave, which can form at the interface between uniform linear media and periodic optical lattice with nonlocal pho-torefractive diffusion nonlinearity. This type of surface wave originates not only from the gaps but also from the bands of the optical bandgap structures, which are different from surface lattice solitons and can be classified into three kinds, i.e., band lattice surface wave, gap lattice surface wave, and outside bandgap lattice surface wave. The diffusion nonlinearity ensures the concentration of light energy near the boundary of optical lattice and brings a downward shift of the optical bandgap structure.