On-demand terahertz surface wave generation with microelectromechanical-system-based metasurface

Abstract

During the past decade, metasurfaces have shown great potential to complement standard optics, providing novel pathways to control the phase, amplitude, and polarization of electromagnetic waves utilizing arrays of subwavelength resonators. We present dynamic surface wave (SW) switching at terahertz frequencies utilizing a mechanically reconfigurable metasurface. Our metasurface is based on a microelectromechanical system (MEMS) consisting of an array of micro-cantilever structures, enabling dynamic tuning between a plane wave (PW) and a SW for normal incidence terahertz radiation. This is realized using line-by-line voltage control of the cantilever displacements to achieve full-span ( 2 π ) phase control. Full-wave electromagnetic simulations and terahertz time-domain spectroscopy agree with coupled mode theory, which was employed to design the metasurface device. A conversion efficiency of nearly 60% has been achieved upon switching between the PW and SW configurations. Moreover, a nearly 100 GHz working bandwidth is demonstrated. The MEMS-based control modality we demonstrate can be used for numerous applications, including but not limited to terahertz multifunctional metasurface devices for spatial light modulation, dynamic beam steering, focusing, and beam combining, which are crucial for future “beyond 5G” communication systems.

Tunable Bound States in the Continuum in a Reconfigurable Terahertz Metamaterial

“…Fortunately, a raft of possibilities to realize tunable MMs have been developed including electrical, magnetic, thermal, and optical stimuli. [40][41][42][43][44][45][46] This, in turn, provides pathways to create reconfigurable BIC MMs.…”

Dynamic radar jamming metasurface with amplitude and phase modulation

“…While the active coding metasurface can be dynamically controlled to gain multifunction in a single programmable platform. By controlling the active devices such as switching diodes [17], varactor diodes [18], and micro-electromechanical systems (MEMS) switch [19], the active coding metasurface has been proved to have the amplitude or phase modulation function. Guo and Li utilized an energy-selective-surface layer and a copper layer to realize dynamic phase modulation [20].…”

Broadband Terahertz Silicon Membrane Metasurface Absorber

“…The terahertz frequency regime, lying between microwave and mid-infrared frequencies, has captured the attention of scientists and engineers due to its rich scientific potential. − Technological advances related to THz waves are not only driven by high-efficiency sources, but also by a variety of high-quality functional devices, including waveplates, beam splitters, lenses, reflectors, and absorbers. − In recent years, metasurfaces have become a hotspot for effectively manipulating waves from microwave through visible frequencies. − The ultrathin nature of metasurfaces, relative ease of fabrication, and subwavelength resolution offer considerable potential for THz device miniaturization and system integration.…”