Nonlinear surface polaritons in anisotropic Kerr-type metamaterials

We study p-polarized nonlinear surface polaritons (NLSPs) localized at the interface between an anisotropic Kerr-type metamaterial and a conventional, linear isotropic material. We generalize the conservation law governing the electric field components of a p-polarized wave travelling in conventional media to the anisotropic Kerr-type metamaterials. Based on the law, the exact dispersion relation for the NLSPs has been derived that can reproduce all the earlier results on the p-polarized surface polaritons under corresponding conditions. The effects of the electric field at the interface and nonlinearity on the properties of the NLSPs have been discussed for five distinct frequency intervals. The result suggests that the group velocities of the NLSPs can be switched between positive and negative values by changing the electric field at the interface, nonlinearity and frequency, which might be used in group-velocity engineering. We also discuss the propagating directions of the phase, energy and group velocities.