Asymmetric transmittance of the surface plasmon-polariton +1 Bragg beams

We investigate theoretically the propagation of a surface plasmon polariton(SPP) propagating along the metal/air interface where metallic part consists of two metallic sections with a periodically modulated interface between them. We find that such a structure exhibits asymmetric transmittance for a SPP incident on it from opposite sides. This asymmetric transmission originates from diffraction which occurs at the in-plane grating between two metals which implies the suppression of the 0-order SPP Bragg beam and the diffraction efficiencies of the +1 and -1 Bragg beams can be controlled by varying the lattice constant of the grating and/or the angle of incidence. This property is predicted by using a theoretical thin phase screen approach and verified by computer simulation calculations.