Article
Chemistry, Multidisciplinary
Kirill A. Kuznetsov, Daniil A. Safronenkov, Petr Kuznetsov, Galiya Kh Kitaeva
Summary: This study experimentally demonstrated the efficient generation of terahertz radiation by a dipole photoconductive antenna based on a thin island film of a topological insulator, with comparable performance to a semiconductor photoconductive antenna of greater thickness. Current-voltage characteristics of Bi1.9Sb0.1Te2Se were studied, and possible mechanisms for generating terahertz waves were analyzed by comparing the characteristics of terahertz radiation from electrically biased and unbiased topological insulators.
APPLIED SCIENCES-BASEL
(2021)
Article
Engineering, Electrical & Electronic
Yilin Feng, Lidan Cao, Yan Zhang
Summary: A device based on slot antennas has been designed to stimulate terahertz SPPs and control their wave front simultaneously, which can simplify the design and fabrication of integrated SPPs devices. Adjustment of geometric parameters allows for phase modulation and improved conversion efficiency of terahertz propagating waves into surface waves.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2021)
Article
Chemistry, Multidisciplinary
Zijie Gao, Yanpeng Shi, Meiping Li, Jinmei Song, Xiaoyu Liu, Xiaodong Wang, Fuhua Yang
Summary: Tunable extraordinary optical transmission (EOT) with graphene is achieved in the terahertz frequency regime using a novel metallic ring-rod nested structure, leading to the generation of double-enhanced transmission peaks primarily originating from the excitation of localized surface plasmon resonances (LSPRs). By regulating the Fermi energy (E-f) of the graphene, an adjustment from bimodal EOT to unimodal EOT is obtained, demonstrating promising application prospects in frequency-selective surfaces, communication, filtering, and radar.
Article
Optics
Ushaben Keshwala, Sanyog Rawat, Kanad Ray
Summary: The article presents the design and detailed analysis of a DNA-shaped antenna for terahertz and sub-terahertz applications, which achieves dual-band characteristics with enhanced bandwidth by changing the ground from full to partial.
Review
Chemistry, Multidisciplinary
Mikhail Tarasov, Aleksandra Gunbina, Artem Chekushkin, Vyacheslav Vdovin, Aleksei Kalaboukhov
Summary: Integrated quasi-optical cryogenic terahertz receivers consist of various components such as detectors, filters, interferometers, and metamaterials, which were fabricated and experimentally studied on the same platform. These components were designed using different numerical simulation methods, with filters utilizing periodic frequency-selective surfaces and detector arrays requiring a complete analysis of the finite structure. The spectral characteristics of the filters, interferometers, and antenna arrays were measured in the frequency range of 50-600 GHz.
APPLIED SCIENCES-BASEL
(2021)
Article
Optics
Benwen Chen, Shengxin Yang, Jian Chen, Jingbo Wu, Ke Chen, Weili Li, Yihui Tan, Zhaosong Wang, Hongsong Qiu, Kebin Fan, Caihong Zhang, Huabing Wang, Yijun Feng, Yunbin He, Biaobing Jin, Xinglong Wu, Jian Chen, Peiheng Wu
Summary: Thermally activated Janus metasurfaces with phase change materials can produce designed phase delays, enabling reconfigurable THz Janus metasurfaces. This allows for asymmetric focusing of THz waves and directional THz holography with free-space image projections, and the information can be manipulated via temperature and incident THz wave direction. This research offers a common strategy for the reconfigurability of Janus metasurfaces and has potential applications in THz optical information encryption, data storage, and smart windows.
LIGHT-SCIENCE & APPLICATIONS
(2023)
Article
Optics
Mingxiang Stephen Li, Rajour Tanyi Ako, Sharath Sriram, Christophe Fumeaux, Withawat Withayachumnankul
Summary: Uniform illumination is crucial for tera-hertz imaging, and converting a Gaussian beam to a flat top beam is necessary. This study presents a single metasurface lens that efficiently converts a quasi-Gaussian beam to a flat top beam in the near-field region. The design process is divided into three sections to minimize simulation time, and experimental validation confirms high-efficiency conversion at 275 GHz.
Article
Multidisciplinary Sciences
Mohamed Mamdouh M. Ali, Shoukry Shams, Mahmoud Elsaadany, Ghyslain Gagnon, Ke Wu
Summary: This paper introduces the use of graphene to implement a reconfigurable printed ridge gap waveguide structure in the terahertz frequency range for the first time. This guiding structure exhibits low loss and is suitable for both millimeter and terahertz wave applications.
SCIENTIFIC REPORTS
(2022)
Article
Chemistry, Multidisciplinary
Hui Li, Chenglong Zheng, Hang Xu, Jie Li, Chunyu Song, Jitao Li, Liang Wu, Fan Yang, Yating Zhang, Wei Shi, Jianquan Yao
Summary: This paper demonstrates an all-silicon metasurface that converts arbitrary incident polarization states to circular polarization states through mutual interference. The conversion intensities can be controlled using the behavior of polarization states defined on the Poincare sphere. The metasurface exhibits broadband circular dichroism and has potential applications in various fields.
Article
Engineering, Electrical & Electronic
Walter Fuscaldo, Alessandro Galli, David R. Jackson
Summary: The radiation pattern of 1-D unidirectional leaky-wave antennas (LWAs) is typically derived from the analysis of the space factor (SF) only. However, including the cosine-type element pattern term is necessary when the antenna aperture is characterized by a longitudinal radiating current. The inclusion of the element pattern significantly affects the beam properties, shifting the beam peak and narrowing the beamwidth.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2023)
Article
Optics
Guozhen Zhang, Qirui Fang, Ying Li, Jun Yang, Minggang Hu, Jian Li, Guangsheng Deng, Zhiping Yin, Hongbo Lu
Summary: This paper presents a novel sub-terahertz liquid crystal (LC) phase shifter based on digital coding metasurfaces. The proposed structure changes the state of the phase shifter by switching the voltage on every grating, allowing the deflection of LC molecules within a subregion. Four switchable coding states of the phase shifter are obtained experimentally. This work provides a novel idea for wavefront modulation of phase.
Article
Spectroscopy
Bin Li, Xiao Zhang, Rong Wang, Yu Mei, Jianjun Ma
Summary: A theoretical model combining integral equation and radiative transfer theory was used to fit the measured data on scattering behavior of THz waves interacting with plant leaves. The model demonstrated good agreement for water status evaluation with consideration of variation in leaf thickness and surface roughness. The study investigated the applicability of THz waves for water status monitoring under different conditions such as temperature, salinity, and polarization in reflection and transmission geometries.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2021)
Article
Chemistry, Analytical
Laurent Le Coq, Nicolas Mezieres, Paul Leroy, Benjamin Fuchs
Summary: This study focuses on the three-dimensional characterization of antenna far field patterns at terahertz frequencies, addressing the challenges of accurately measuring the phase of the electric field. Models and procedures to estimate errors caused by mechanical and electrical issues are proposed, with experimental validation demonstrating the effectiveness of the approach.
Article
Optics
Xie-Qiu Yu, Yu-Shan Zeng, Li-Wei Song, De-Yin Kong, Si-Bo Hao, Jia-Yan Gui, Xiao-Jun Yang, Yi Xu, Xiao-Jun Wu, Yu-Xin Leng, Ye Tian, Ru-Xin Li
Summary: Using terahertz surface waves, electron energy gain of up to 1.1 MeV and effective acceleration gradient of up to 210 MV m(-1) can be achieved, enabling potential phase-space control and application in compact microscopy, radiation sources, and cancer therapies.
Article
Optics
Hui-Jun Zhao, Fei Fan, Tian-Rui Zhang, Yun-Yun Ji, Sheng-Jiang Chang
Summary: To enhance and actively control terahertz anisotropy and chirality, a THz composite device consisting of a liquid crystal layer and an anisotropic metasurface has been designed and fabricated. By manipulating the spatial orientation of the liquid crystal optical axis, the device exhibits enhanced or offset anisotropy and tunable phase-shift range. The destruction of mirror symmetry in the LC-Si anisotropic medium enables active modulation and achieves high circular dichroism. This composite device demonstrates potential applications in THz polarization conversion and chiral transmission.
PHOTONICS RESEARCH
(2022)