On-demand terahertz surface wave generation with microelectromechanical-system-based metasurface
On-demand terahertz surface wave generation with microelectromechanical-system-based metasurface
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DOI：
10.1364/optica.444999
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发表时间：
2022-01-20
期刊：
影响因子：
10.4
通讯作者：
Zhang, Xin
中科院分区：
文献类型：
--
作者：
Chen, Chunxu;Kaj, Kelson;Zhang, Xin
在过去的十年中，超颖表面已经显示出巨大的潜力，以补充标准的光学，提供新的途径来控制相位，振幅和偏振的电磁波利用阵列的亚波长谐振器。我们提出了动态表面波（SW）开关在太赫兹频率利用机械可重构的超表面。我们的超表面是基于微机电系统（MEMS）组成的微悬臂梁结构的阵列，使平面波（PW）和SW之间的动态调谐垂直入射太赫兹辐射。这是通过对悬臂位移进行逐线电压控制来实现的，以实现全跨度（2 π）相位控制。全波电磁模拟和太赫兹时域光谱符合耦合模理论，这是用来设计超颖表面器件。在PW和SW配置之间切换时，已经实现了近60%的转换效率。此外，近100 GHz的工作带宽被证明。我们展示的基于MEMS的控制模式可用于多种应用，包括但不限于用于空间光调制、动态光束转向、聚焦和光束组合的太赫兹多功能超表面器件，这些对于未来的“超越5G”通信系统至关重要。(C)2021 Optica出版集团根据Optica开放获取出版协议的条款
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 pi) 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. (C) 2021 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement