Reconfigurable multifrequency and wide-angle directional beaming of light from a subwavelength metal slit with graphene metasurfaces

Abstract

Directional beaming of light from a subwavelength slit surrounded with phase-gradient metasurfaces can be realized with very high efficiencies, but the available optical proposals suffer from narrow bandwidth after the fabrication process and cannot be reconfigured dynamically with switchable frequencies. Here we demonstrate reconfigurable multifrequency directional beaming by placing a graphene ribbon array at two sides of a subwavelength metallic slit. Each graphene ribbon works with the metallic film to fulfill the magnetic response, and the resultant reflection phase can cover full 0–2π range by changing the chemical potential of graphene. The on-axis and off-axis directional beams can be formed by properly arranging the chemical potentials of graphene ribbons to serve as meta-couplers between surface waves and propagating waves. Thanks to the negligible interaction between vertically stacked graphene sheets, the beaming frequencies and angles can be broadened by use of double layers of the graphene ribbon array.

Polarization-multiplexing graphene-based coding metasurface for flexible terahertz wavefront control

“…In comparison, graphene has recently garnered significant attention due to its wide range of tunable conductivities, fast response speed, and polarization independence [29,30]. It has been extensively used to fabricate various tunable terahertz meta-devices, including reconfigurable specialized beam generators, tunable meta-lenses, controllable metacouplers, and so on [31][32][33][34][35][36][37][38][39]. Whereas, most existing graphene-based coding metasurfaces can only respond to a single polarization mode of the incident wave, which is considerably unfavorable for high integration and large capacity of terahertz communication [40][41][42][43].…”

High-Quality Graphene-Based Tunable Absorber Based on Double-Side Coupled-Cavity Effect

“…Monolayer graphene, a semimetallic two-dimensional material of hexagonally arranged carbon atoms, has attracted significant attention due to its extraordinary mechanical, thermal, electronic, and optical properties. Similar to three-dimensional noble metal nanoparticles, monolayer graphene can also support surface plasmon-polaritons (SPPs), and it exhibits more remarkable properties such as flexible electrical tunability, strong light confinement, and relatively low ohmic losses [1][2][3][4]. Due to these unique characteristics, graphene-based absorbers, optical modulators, logic processors, power splitters, optical filters, and biochemical sensors have been realized [5][6][7][8][9][10][11][12][13].…”