Stable solitons in the 1D and 2D generalized nonlinear Schrödinger equations with the periodic effective mass and PT-symmetric potentials

We explore the influence of effective-mass modulation on beam dynamics in the one- and two-dimensional generalized linear and nonlinear Schrödinger equations with parity-time (PT) symmetric periodic potentials. In the linear regime, we successively give the first and second PT threshold curves of optical lattices under the modulation of different effective masses, and analyze the associated band structure and diffraction dynamics of beams. In the Kerr-nonlinear regime, a family of novel optical solitons can exist in the semi-infinite gap. As the effective-mass parameter grows, the existing range of these solitons gradually increases whereas their stable domain gradually diminishes. Two-dimensional (2D) stability analysis reveals that the larger effective-mass parameter, gain-and-loss amplitude, and propagation constant may more easily lead to instable solitons. The 1D and 2D transverse power flows are also examined. Our results may open a new design window for the nonlinear optics in the effective mass and PT-symmetric lattices and other related fields.