A metasurface for polarization-controlled-phase directional coupling of surface plasmon polaritons

Abstract Surface plasmon polaritons (SPPs) are special electromagnetic modes propagating along the metal-dielectric interfaces, which have attracted widespread attention in various scientific communities due to well-confined surface waves and enhanced optical fields. Therefore, the effective directional excitation and control of SPPs are research hotspots in the field of nanophotonics and plasmonics, and the most extreme challenges. Herein, we demonstrate a metasurface for phase modulation and effective directional excitation of the SPPs. The dynamic control of phase is realized by appropriately arranging rectangular apertures in a gold film. By carving a periodic array of grooves on one side of the rectangle apertures, Bragg reflection increases the intensity of SPPs propagated to the other side, enabling directional and efficient excitation.