The competition between strong localization and radiative damping is studied for surface-plasmon polaritons propagating along a finite, randomly rough metallic surface that is periodic on average, by means of both numerical simulations and perturbation-theoretic calculations. Our results show that localization is the predominant contribution to the exponential decay of the transmission. In addition, it is found that the localization length is larger for a frequency in an allowed band of the surface-plasmon polariton dispersion relation for the underlying periodic structure than it is for a frequency in the vicinity of a gap. No significant leakage inhibition is observed near the band edge.

• Received 30 May 1996

DOI:https://doi.org/10.1103/PhysRevB.56.1103