Behaviors of surface plasmon polaritons generated on the surface of silver nanowires with a square cross-section embedded in Kerr nonlinear medium

Behaviors of surface plasmon polaritons (SPPs) generated on the surface of silver nanowires with a square cross section by coaxial Gaussian beams in Kerr nonlinear mediums are studied numerically. SPP modes with enhanced propagation and confinement are realized at the vertices of the nanowire's cross-section due to the nonlinear effect of the Kerr mediums. Influences of the nonlinearity of the Kerr mediums, the lateral dimension of the nanowires and the polarization direction of the Gaussian beams on the SPP modes are studied specifically. Higher nonlinearity of the Kerr mediums may even result in amplification of the SPP modes within certain ranges. Larger lateral dimensions may cause greater localizing effect of the nanowire which may result in decreased propagation and increased confinement of the SPP modes. Variation of the polarization direction of the Gaussian beams affects only the intensity of the SPP modes and its lateral distribution, but not the overall propagation of the SPP modes. Nanowires with square cross sections of dimensions around 20–30 nm and Gaussian beams with polarization direction paralleled to the diagonal of the cross section of the nanowire are conducive to the propagation of the SPP modes.