Actively controlling the amplitude and phase of terahertz (THz) wave is of great significance for THz broadband wireless communication and high-resolution THz imaging. In this paper, we present a THz amplitude and phase modulator based on electrically triggered vanadium dioxide (VO ₂ ) reconfigurable metasurface. The unit cell of the device consists of three concentric split-rings-rings (SRRs) on the sapphire substrate, i.e., one VO ₂ -split-ring (VSR) and two metal SRRs. The VSR is embedded between two metal SRRs. The resonance mode, resonance intensity and surface current distribution in the unit cell can be dynamically manipulated by electrically triggering the insulator-to-metal-transition (IMT) of the VO ₂ . The sample is fabricated using a surface micromachining process and characterized by a THz time-domain-spectroscopy (TDS) system. The experimental results show that, 90 degrees phase shift is achieved in a broad bandwidth of 70 GHz. Meanwhile, the amplitude modulation depth reaches 71% at 0.79 THz. The transmission and the phase shift are calculated by an equivalent circuit model, and simultaneously simulated using a full-wave circuit simulation software based on the Method of Moments (MoM). The calculation and simulation results agree with the experimental results. The device has potential applications in THz imaging, broadband wireless communications and array phase controlling.

中文翻译：

---

用于太赫兹波的幅度和相位调制的电触发 VO ₂可重构超表面

主动控制太赫兹（THz）波的幅度和相位对于太赫兹宽带无线通信和高分辨率太赫兹成像具有重要意义。在本文中，我们提出了一种基于电触发二氧化钒 (VO ₂ ) 可重构超表面的太赫兹幅度和相位调制器 。器件的晶胞由蓝宝石衬底上的三个同心开口环（SRR）组成，即一个VO ₂ 开口环（VSR）和两个金属SRR。VSR 嵌入在两个金属 SRR 之间。可以通过电触发 VO ₂的绝缘体到金属转变 (IMT) 来动态控制晶胞中的谐振模式、谐振强度和表面电流分布 . 该样品是使用表面微加工工艺制造的，并通过太赫兹时域光谱 (TDS) 系统进行表征。实验结果表明，在 70 GHz 的宽带宽内实现了 90 度相移。同时，幅度调制深度在 0.79 THz 时达到 71%。传输和相移通过等效电路模型计算，同时使用基于矩量法（MoM）的全波电路仿真软件进行仿真。计算和仿真结果与实验结果一致。该器件在太赫兹成像、宽带无线通信和阵列相位控制方面具有潜在应用。