Coupling and Decoupling of Surface Plasmon Polaritons with a Double Period Metallic Grating

Herein, a numerical and experimental study of the interaction of a directional beam of light with metallic surfaces with two periodic components is presented. The periods of these two components are chosen in such a way that, through one of them, light is coupled into surface plasmon polaritons (SPPs) and, through the other one, the SPPs are decoupled as a propagating beam in another direction. This interaction can produce a propagating beam of light that involves in its trajectory the passage through an SPP state, providing thus a means of studying the effects of SPP coupling on the state of coherence of the emerging field. These coupling/decoupling effects are studied numerically, and experimental evidence of the generation of such SPP decoupled beams is presented. The effect of this double scattering process on the temporal properties of short light pulses, reflected by a double period metallic grating, is also studied.