Defect solitons in two dimensional optical lattices with line defect

The existence, stability and propagation properties of defect solitons in two-dimensional optical lattices with a line defect are investigated analytically and numerically. When line defects with various defect intensities are introduced into two-dimensional optical lattices, defect solitons can exist in different bandgaps. Some unique characteristics show that the line defect embedded into two-dimensional optical lattices can profoundly influence the shape, stability and propagation of solitons. For a positive defect, the solitons only exist in the semi-infinite gap and cannot be stable in the high power region. For a negative defect, the solitons can exist not only in the semi-infinite gap, but also in the first gap;the solitons are stable in the moderate power region in the first gap.