Self-focusing and self-bending of surface plasmons in longitudinally modulated metasurfaces

Abstract We propose an effective method to manipulate the flow of surface plasmons propagating in a longitudinally modulated metasurface formed by periodic silver ridge gratings. We show that band structures with elliptical, flat and hyperbolic dispersion profiles can be achieved in surface ridge grating metasurface with different ridge height and width, therefore, the propagation behaviors of the surface plasmons in the metasurface can be actively molded in longitudinally modulated ridge grating metasurface. Both self-focusing and self-bending propagation of surface plasmons are demonstrated. Such longitudinally modulated metasurfaces provide a good platform to steer or mold the flow of surface plasmons, which may have many potential applications in nanoplasmonics such as on-chip directional routing of surface plasmons, subwavelength beam steering and on-chip signal processing.