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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 ( ) 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.
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Terahertz Beam Steering with Curved Metasurfaces
Considerable recent research interest has focused on the possibility of using metasurfaces for manipulation of terahertz wavefronts. For example, metasurfaces allow a beam to be targeted in any desired direction using strategically placed meta-elements. With rapid prototyping techniques, metasurfaces can be fabricated quickly and at a low cost. These techniques also permit the fabrication of metasurfaces on flexible substrates which can be bent easily. This opens the possibility of employing such devices as conformable arrays on non-flat surfaces. To explore this idea, we experimentally and numerically analyze the performance of a terahertz metasurface printed on paper, as a function of its radius of curvature. We observe that when the metasurface is bent, the direction of the refracted beam is minimally impacted and the performance of the metasurface remains very similar to when it is flat. This conclusion will simplify the design and modeling criteria for conformable metasurfaces.
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- PAR ID:
- 10420334
- Date Published:
- Journal Name:
- Journal of Infrared, Millimeter, and Terahertz Waves
- ISSN:
- 1866-6892
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1007/s10762-023-00918-1
