Lossless and stable propagation of surface plasmon polaritons in quasi-PT potential

We propose a scheme to study the propagation properties of surface plasmon polaritons (SPPs) in a dielectric/metal/dielectric waveguide with a refraction index of the dielectric modulated as quasi-PT -symmetric potentials. By treating the propagation loss of SPPs as the absorption background, we prove that a total gain–loss balance system which allows SPPs losslessly and stably propagating can be achieved. In addition, the propagation robustness of single peak and dipole peak transverse structured SPPs in quasi-PT -symmetric potentials under noise perturbations is discussed. The results may have certain significance for expanding applications of non-Hermitian optics in micro-/nano-optical information processing.