Ultrathin metasurface with topological transition for manipulating spoof surface plasmon polaritons

TL;DR

This paper introduces an ultrathin metasurface with a topological transition that can manipulate spoof surface plasmon polaritons at low frequencies, enabling advanced wave control phenomena with low loss and integration potential.

Contribution

The work presents the first experimental demonstration of a topological transition metasurface for spoof SPPs at microwave and terahertz frequencies, expanding control capabilities beyond optical frequencies.

Findings

Demonstrated frequency-dependent spatial localization

Achieved non-diffraction propagation of spoof SPPs

Observed negative refraction and dispersion-dependent spin-momentum locking

Abstract

Metasurfaces, with intrinsically planar nature and subwavelength thickness, provide us unconventional methodologies to not only mold the flow of propagating waves but also manipulate near-field waves. Plasmonic metasurfaces with topological transition for controlling surface plasmon polaritons (SPPs) recently have been experimentally demonstrated, which, however, are limited to optical frequencies. In this work, we proposed and experimentally characterized an ultrathin metasurface with the topological transition for manipulating spoof SPPs at low frequency. We demonstrated rich interesting phenomena based on this metasurface, including frequency-dependent spatial localization, non-diffraction propagation, negative refraction, and dispersion-dependent spin-momentum locking of spoof SPPs. Comparing with traditional three-dimensional metamaterials, our metasurface exhibits low propagation loss and compatibility with the photonic integrated circuit, which may find plenty of applications in spatial multiplexers, focusing and imaging devices, planar hyperlens, and dispersion-dependent directional couplers, in microwave and terahertz frequencies.