Terahertz Sensor With Resonance Enhancement Based on Square Split-Ring Resonators

Abstract

A novel design of a nearly perfect metamaterial absorber based on square split-ring resonators for terahertz sensing applications is proposed and analyzed. The design in this report is simulated and analyzed by using standard numerical simulation software. Magnetic and electric resonant field enhancement in the impedance matched absorber cavity enables stronger interaction with the dielectric analyte. The proposed structure is based on the simultaneous increase in the electromagnetic field and the surface current distribution at the resonance frequency. An absorptivity of 99% is achieved at 0.53 THz with a narrow resonance peak and a Q-factor of 44.17. At a fixed analyte thickness, the resonance frequency is sensitive to the refractive index of the surrounding medium. The influence of the thickness of the covering sample on the sensitivity and absorption coefficient of the absorber is comprehensively analyzed, and the reported design can be used as a refractive index sensor with a high sensitivity of 126.0 GHz/RIU and a figure of merit of 10.5 in the refractive index range from 1.0 to 2.0 at an analyte thickness of 15.0 µm. The results show that the sensor has high sensitivity to the analyte covering it. The sensor not only exhibits good sensitivity to thin analytes but also shows high sensitivity to analytes more than 10 µm thick in the terahertz low frequency band. Specifically, the sensitivity changes rapidly when the thickness of the sample changes in the range of 0-6 µm, but slowly in the range of 6-16 µm. In general, the response of the resonance frequency to changes in the refractive index of the sample becomes more sensitive as the thickness of the sample is increased from 0 to 16 µm . The reported terahertz sensor of a metamaterial absorber has potential applications in biomedical sensing and trace detection of substances.

High-Sensitivity Terahertz Biosensor Based on Plasmon-Induced Transparency Metamaterials

“…Cong et al [31] Metamaterial absorber 2015 139.2 GHz/RIU Cheng et al [16] Fano resonance 2020 160 GHz/RIU Xiong et al [32] Split-ring resonator 2021 126 GHz/RIU Fan et al [33] Chiral metasurface 2021 223 GHz/RIU Lang et al [29] EIT metamaterials 2023 270.4 GHz/RIU Proposed biosensor PIT metamaterials 2023 281.25 GHz/RIU…”

Terahertz toroidal dipole metamaterial sensors for detection of aflatoxin B1

“…These values of sensitivity and Q-factor are superior to those of most current metamaterial systems. [30][31][32][33][34] The toroidal dipole sensor is then experimentally fabricated for detection of aflatoxin B1 (AFB1). The results demonstrate that for an analyte of AFB1 solution the minimum measurable concentration can be as low as 0.001 µg•ml −1 .…”

Numerical analysis of a highly sensitive SOI MRR refractive index sensor with performance enhancement using graphene and gold

“…Additionally, the paper's architecture may be directly compared to a planar sensor but with increased sensitivity. Simple geometry was used in the modeling, and it may be arranged periodically to create massive metamaterial structures with several of these resonators for THz sensing with increased sensitivity [ [44] , [45] , [46] , [47] ]. However, since this further adds design complexity, a better sensing capacity for our suggested structure would help to address this problem and give acceptable sensing accuracy with a more simplistic model.…”