Control of plasmon-polariton vortices on the surface of a metal layer.

Surface plasmon polaritons (SPPs) can be excited at the interface of a metal layer and a dielectric layer by various methods. If an inhomogeneity of permittivity with a curvilinear boundary is created in the metal layer by the external electric field, the incident SPPs and the reflected ones from this inhomogeneity interfere with one another. A nonrectangular vortex lattice appears when such SPP interference occurs, and the lattice configuration can be controlled by varying the external electric field. Based on control of the SPP vortex lattice and reading out of the vortex localization, the plasmon logic gates "AND," "OR," and "NOT" can be realized. These logic gates represent a functionally complete basis for logical operations in processors operating at optical frequencies.