Generalized approach to plasmonic phase modulation in topological bi-gratings

Abstract

We study the role of optical momenta in surface plasmon excitation by topological bi-gratings. We analyze plasmonic structures composed of rectangular apertures rotating in 2D space with given rates, which couple to specific plasmon trajectories. We experimentally demonstrate the control of plasmonic propagation through premeditated design of the gratings, which interact with linear, spin, and orbital angular momentum of light. We show that these trajectories can be selected purely through momenta modulation with numerous degrees of freedom for a given structure geometry. Moreover, it is shown that the symmetry of the final plasmonic distribution is defined by selecting specific rotation rates, and that it can be different from the original grating symmetry.