High-sensitivity polarization-independent terahertz Taichi-like micro-ring sensors based on toroidal dipole resonance for concentration detection of Aβ protein
Liu Wencan,
Zhou Xinwei,
Zou Shucai,
Hu Zhengguang,
Shen Yun,
Cai Mengqiang,
Lin Dongdong,
Zhou Jia,
Deng Xiaohua,
Guo Tianjing,
Lei Jiangtao
Affiliations
Liu Wencan
Department of Physics, School of Physics and Materials Science, Nanchang University, Xuefu Avenue 999, Nanchang City330031, China
Zhou Xinwei
Department of Physics, School of Physics and Materials Science, Nanchang University, Xuefu Avenue 999, Nanchang City330031, China
Zou Shucai
Department of Physics, School of Physics and Materials Science, Nanchang University, Xuefu Avenue 999, Nanchang City330031, China
Hu Zhengguang
Department of Physics, School of Physics and Materials Science, Nanchang University, Xuefu Avenue 999, Nanchang City330031, China
Shen Yun
Department of Physics, School of Physics and Materials Science, Nanchang University, Xuefu Avenue 999, Nanchang City330031, China
Cai Mengqiang
Institute of Space Science and Technology, Nanchang University, Xuefu Avenue 999, Nanchang City330031, China
Lin Dongdong
Department of Physics and Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo, Zhejiang315211, China
Zhou Jia
Institute of Space Science and Technology, Nanchang University, Xuefu Avenue 999, Nanchang City330031, China
Deng Xiaohua
Department of Physics, School of Physics and Materials Science, Nanchang University, Xuefu Avenue 999, Nanchang City330031, China
Guo Tianjing
Institute of Space Science and Technology, Nanchang University, Xuefu Avenue 999, Nanchang City330031, China
Lei Jiangtao
Department of Physics, School of Physics and Materials Science, Nanchang University, Xuefu Avenue 999, Nanchang City330031, China
Terahertz (THz) metamaterial sensor is a newly-developing interdisciplinary technology, which combines the essential characteristics of THz spectroscopy and metamaterials, to obtain better sensitivity for trace detection of the different target analytes. Toroidal dipole resonances show great sensing potential due to their suppression of the radiative loss channel. Here, we found a high-quality planar toroidal dipole resonance in the breaking Chinese Taichi-like ring and then designed a novel polarization-independent terahertz toroidal sensor by combining four Taichi-like rings into a cycle unit. The sensor shows high-sensitivity sensing characteristics for the ultrathin analyte and refractive index. The optimized sensitivity of pure analytes under 4 μm coating thickness can numerically reach 258 GHz/RIU in the corresponding ∼1.345 THz frequency domain, which is much higher than that of previously reported sensors. We further fabricated experimentally the sensor and demonstrated its fascinating polarization-independent characteristics. Finally, it was successfully applied to the low-concentration detection (ranging from 0.0001 mg/mL to 10 mg/mL) of Aβ protein associated with Alzheimer’s disease. Our high-sensitivity polarization-independent THz toroidal dipole sensor would give access to rich applications in label-free biosensing.
