Propagation length enhancement of surface plasmon polaritons in ultrafine Au nanodisk array, the role of kinky breather and periodic lump

Abstract

We deal with a non-radiative approach to investigate the propagation of Surface Plasmon Polaritons (SPPs) in an Au nanodisk array in touch with an analyte medium. We obtain a nonlinear equation with solutions as in the form of kinky breather and periodic lump. The nonlinear response depends on the dielectric constant and wavenumber variation in analyte zone. It is shown that the periodic feature can guarantee the enhanced propagation length of SPPs stationary modes. Analytical results also reveal the occurrence of Fano resonance while numerical results show that the propagation length can go beyond 56 μm. On the other hand, using Kretschmann-Raether approach, we reach the Fano resonance in consequence of the interaction of dark and bright plasmon modes which is in agreement with our model and interpretation. Our nonlinear model can give a sketch for SPPs propagation especially in bio-sensing application.