Propagation and localization of a surface plasmon polariton on a finite grating

Abstract

The propagation of a surface plasmon polariton along a finite grating is studied numerically. It is shown that there is a forbidden band of frequencies. The transmittivity of the system exhibits oscillations that are attributed to finite size effects. We also investigate the properties of acceptor defects, which produce localized states. The excitation of these modes yields a peak of the transmittivity within the gap and an enhancement of the near field. Finally, we study the transmittivity and the near field for random gratings that are periodic on average. We observe that the gap width decreases. In addition, we show that the reflectivity of the finite grating increases when the length of the finite grating increases for a frequency out of the gap but close to the band edge. This behavior indicates the presence of Anderson localization.