Near-wavelength diffraction gratings for surface plasmon polaritons

In this Letter, we study numerically diffraction gratings for surface plasmon polaritons. Investigated plasmonic gratings consist of a periodic set of dielectric ridges located on the metal surface. The grating period is comparable with the wavelength of the incident wave. The simulation results obtained within the rigorous coupled-wave analysis framework have shown that the SPP diffraction on a plasmonic grating with parasitic scattering suppression is remarkably close to the diffraction of a TE-polarized plane wave on a conventional grating. A compact and efficient reflecting plasmonic grating is considered as an example. The presented results can be used for the design of high-efficiency two-dimensional optical elements for steering surface plasmon propagation.