Transmission properties of one-dimensional metallic and left-handed material gratings

We provide rigorous numerical calculations (using the rigorous coupled-wave analysis) of transmission spectra of various metallic and metamaterial one-dimensional gratings and identify plasmonic resonances responsible for enhanced transmission. We argue that the most important mechanism which influences the resonant transmission is the coupling of incident electromagnetic wave with two types of plasmonic wave: lengthwise plasmon, which propagates along the grating, and crosswise plasmon excited in air gaps.