Surface plasmons propagation along metallic rough diffraction gratings

In this work, the effect of roughness on surface plasmon propagation along metallic gratings is investigated. In the case of a shallow sinusoidal grating, modeling that takes into account the surface roughness shows the modification of the coupling properties of the plasmon modes. In the case of a deep sinusoidal rough grating, modeling of the SPR response is compared to the experimental one, showing a strengthening of the intra-coupling between forward and backward plasmon modes. This study demonstrates that the effect of the surface roughness on plasmon propagation must be considered especially in the case of deep gratings.