Design of Tunable Terahertz Metamaterial Sensor with Single- and Dual-Resonance Characteristic

Abstract

We present two types of refractive index sensors by using tunable terahertz (THz) metamaterial (TTM) based on two concentric split-ring resonators (SRRs) with different splits. By modifying the distance between SRRs and substrate, TTM shows tunable single- and dual-resonance characteristic. The maximum tuning range of resonance is 0.432 THz from 0.958 THz to 1.390 THz. To demonstrate a great flexibility of TTM in real application, TTM device is exposed on the surrounding ambient with different refractive index (n). The sensitivity of TTM can be enhanced by increasing SRR height, which is increased from 0.18 THz/RIU to 1.12 THz/RIU under the condition of n = 1.1. These results provide a strategy to improve the sensing performance of the metamaterial-based sensing device by properly arranging the geometric position of meta-atoms. The proposed TTM device can be used for tunable filters, frequency-selective detectors, and tunable high-efficiency sensors in the THz frequency range.

Actively MEMS-Based Tunable Metamaterials for Advanced and Emerging Applications

“…With the increased external temperature from 77 K to 400 K, the resonant frequency can be continuously red-shifted 80 GHz for the advanced manipulation of THz waves. Meanwhile, ETAs are widely reported to modify the vertical gap between different metamaterial layers, as shown in Figure 2c,d [60,61]. In such designs, strong coupling resonances are induced between vertical layers.…”

“…Figure 2. ETA-based vertical tuning methods of metamaterials: (a) schematic of thermally tunable split-ring resonators (SRR) based on the pre-stressed metamaterial [58]; (b) optical microscopy image of the eSRR based on metamaterial microarray[59]; (c,d) schematic of MEMS-based tunable THz metamaterial and unit cell by using ETA vertical tuning platforms[60,61]; (e) scanning electron microscope (SEM) images of eSRR-WCM array and unit cell[62].…”

Reconfigurable terahertz metamaterials: From fundamental principles to advanced 6G applications

“…Furthermore, given several control states, one could also demonstrate digital signal operation components, which functioned as logic gates ( Manjappa et al., 2018b ). Apart from the active tuning process leveraging a similar design as MEMS actuators, there were also many other works utilizing material properties for dynamic control of THz waves ( Yang and Lin, 2021 ). However, the tuning of materials usually provides only a single dimension of controlling the resonance, which lacks the ability to manipulate dual resonances independently.…”

A highly stable and sensitive ethanol sensor based on Ru-decorated 1D WO3 nanowires

“…The electrical properties of metal oxide semiconductors (MOS) are related to the ambient atmosphere, and they have the features of low cost, robustness, and easy synthesis. 1–3 Thus, they play a significant role in gas sensing applications to detect toxic, inflammable and explosive gases, 4–6 and are more favored by scientific researchers compared to sensors based on metamaterials 7–10 or nanophotonics. 11–13 MOS-based sensors have been reported over the past several decades, including sensors based on CuO, 14 SnO 2 , 15 In 2 O 3 , 16 Co 3 O 4 , 17 Fe 2 O 3 , 18 ZnO, 19 and NiO, 20 for applications such as monitoring air quality and ensuring industrial safety.…”