title: Defect solitons in two-dimensional optical lattices.
abstract: We report on the existence and stability of solitons in a defect embedded in a square optical lattice based on a photorefractive crystal with focusing saturable nonlinearity. These solitons exist in different bandgaps due to the change of defect intensity. For a positive defect, the solitons only exist in the semi-infinite gap and can be stable in the low power region but not 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. With increasing the defect depth, these solitons are stable within a moderate power region in the first gap while unstable in the entire semi-infinite gap.
authors.affiliation: Department of Physics, South China University of Technology, Guangzhou, 510640, China. Chenwuhe@scut.edu.cn
authors.forename: W H
authors.initials: WH
authors.lastname: Chen
authors.forename: X
authors.initials: X
authors.lastname: Zhu
authors.forename: T W
authors.initials: TW
authors.lastname: Wu
authors.forename: R H
authors.initials: RH
authors.lastname: Li
mesh_terms: D003198:Computer Simulation; D008027:Light; D008420:Manufactured Materials; D008962:Models, Theoretical; D012542:Scattering, Radiation