Defect solitons in nonlinear optical lattices with parity-time symmetric Bessel potentials

Abstract

A theory is presented to investigate the existence and stability of defect solitons in nonlinear optical lattices with parity-time symmetric Bessel potentials. It is found that fundamental and dipole solitons can exist in the self-focusing nonlinear media when their propagation constants are higher than a certain critical value, while they exist in self-defocusing media when the their propagation constants are lower than this critical value. For fundamental solitons, instability growth rate of random noises remains zero and thus the solitons can propagate stably whatever the defect and nonlinearity are. For dipole solitons, only those with low power are stable. The effect of defect on the stable region of dipole solitons is also discussed.