The existence and stability of defect solitons supported by parity-time (PT) symmetric superlattices with nonlocal nonlinearity are investigated. Unlike local PT symmetric system, the nonlocal system considered reveals unusual properties. In the semi-infinite gap, in-phase solitons can exist stably for positive defects or zero defects, but can not exist for negative defects with the strong nonlocality. In the first gap, out-phase solitons are stable for positive defects or zero defects, whereas in-phase solitons are stable for negative defects. The dependence of soliton stabilities on modulation depth of the PT potentials is studied. It is interesting that solitons can exist stably for positive and zero defects when the PT potential is above the phase transition point.

http://arxiv.org/abs/1110.4344
Optics (physics.optics)