Scattering of surface plasmon polaritons on rough metal surfaces is investigated by using scanning near-field optical microscopy. Different scattering regimes, i.e. single, double and multiple scattering, are observed and related to the spatial Fourier spectra of the corresponding near-field optical images. For the regime of strong multiple scattering, the near-field optical images exhibit spatially localized (within 150-250 nm) intensity enhancement by 10-50 times. This feature is attributed to strong localization of surface polaritons due to interference effects in multiple scattering caused by surface roughness. Similar bright light spots are observed with light scattering by silver colloid clusters deposited on glass substrates. Differences and similarities in these scattering phenomena are discussed.
|Journal||Annalen der Physik|
|Publication status||Published - 1999|