Comparison of plasmon surface waves on shallow and deep metallic 1D and 2D gratings.

The propagation of a plasmon surface wave in deep metallic lamellar gratings is shown to be characterized by absorption losses smaller than on a flat metallic-dielectric interface. This feature is due to the formation of a resonance of the electric field inside the groove. Similar to the plasmon surface wave in shallow gratings, this kind of plasmon can lead to total absorption of incident light and to a significant enhancement of the local field density in the vicinity of the grating surface, contrary to the other type of grating anomaly linked with a cavity resonance.