Defect solitons in saturable nonlinearity media with parity-time symmetric optical lattices

We reported the existence and stability of defect solitons in saturable nonlinearity media with parity time (PT) symmetric optical lattices. Families of fundamental and dipole solitons are found in the semi-infinite gap and the first gap. The power of solitons increases with the increasing of the propagation constant and saturation parameter. The existence areas of fundamental and dipole solitons shrink with the growth of saturation parameter. The instability of dipole solitons for positive and no detect induced by the imaginary part of PT symmetric potentials can be suppressed by the saturation nonlinearity, but for negative detect it cannot be suppressed by the saturation nonlinearity. (C) 2013 Elsevier B.V. All rights reserved.