Article
Materials Science, Multidisciplinary
Xin Yan, Chengcheng Huang, Zijing Zhang, Fu Qiu, Wenjia Liu, Ruochen Xu, Ziqun Wang, Zhenhua LI, Xiaofei Hu, Chao Wang, Yonggang Zhang, Haiyun Yao, Lanju Liang, Jianquan Yao
Summary: This paper presents a terahertz metamaterial structure with multiple physical features including EIT-like resonance, Fano resonance, and terahertz wave absorption. The device consists of a metal structure and a GaAs layer, with the conductivity of GaAs adjustable by optical pump. By adjusting the conductivity of GaAs, the resonance can be modulated with a maximum modulation depth of 96.5%. The device exhibits excellent performance in refractive index sensing, with a maximum sensitivity of 513 GHz/RIU and a maximum FOM value of 39.5. It has wide applications in terahertz sensors, slow-light devices, and terahertz modulators.
OPTICAL MATERIALS EXPRESS
(2023)
Article
Optics
Guanchao Wang, Li Li, Chenxiang Liu, Shuai Li, Wenpeng Guo, Yueying Jia, Zhenghao Li, Hao Tian
Summary: This paper proposes a hybrid coupling scheme of a magnetic toroidal and electric dipole metasurface with suppressed radiation loss, which can produce tunable plasmon-induced transparency (PIT) with enhanced slow-light effect in the terahertz regime. The terahertz metasurface is constructed by nesting a dual-split ring resonator (DSRR) inside a ring resonator (RR) to exploit the destructive coherence of hybrid electromagnetic mode coupling at the PIT resonance. The polarization-dependent excitation achieves active tunability of PIT-induced group slowing down by rotating the polarization angle, experimentally achieving a maximum group delay of 3.5 ps. Furthermore, a modified terahertz metasurface with a four-split ring resonator (FSRR) nested in an RR is prepared on photoconductive silicon, demonstrating the pump-controllable group delay effect at the PIT resonance. The large group delay from 2.2 to 0.9 ps is dynamically tunable by adjusting the pump power. The experimental results are in good accord with the theoretical simulations.
PHOTONICS RESEARCH
(2023)
Article
Chemistry, Multidisciplinary
Liang Gao, Chao Feng, Yongfu Li, Xiaohan Chen, Qingpu Wang, Xian Zhao
Summary: This paper investigates a metal-graphene metamaterial device that exhibits a tunable, electromagnetically induced transparency (EIT) spectral response at terahertz frequencies. The device structure, composed of a strip and a ring resonator, induces the EIT effect by serving as the bright and dark mode, respectively. By utilizing the variable conductivity of graphene to dampen the dark resonator, the device can dynamically shift its response frequency over 100 GHz, satisfying the requirement for convenient post-fabrication tunability. The proposed device also exhibits slow-light behavior with a maximum group delay of 1.2 ps. Moreover, the sensing performance is studied, showing a sensitivity of up to 100 GHz/(RIU) and a figure of merit (FOM) value exceeding 4 RIU-1. Therefore, the graphene-based metamaterial provides a new miniaturized platform to facilitate the development of terahertz modulators, sensors, and slow-light applications.
Article
Physics, Condensed Matter
Hanqing Dong, Chengjing Gao, Li Zeng, Dan Zhang, Haifeng Zhang
Summary: This study proposes an electromagnetically induced transparency (EIT) metamaterial based on the bright-dark-quasi-dark theory, which achieves the transition from EIT to electromagnetically induced absorption (EIA) by adjusting the coupling distance. By adding nested split-ring resonators (SRRs), substantial absorption enhancement is achieved, and the structure also exhibits polarization-insensitive characteristics. The influences of different structural parameters on absorption performance are further discussed.
PHYSICA B-CONDENSED MATTER
(2022)
Article
Engineering, Electrical & Electronic
Mingming Chen, Zhongyin Xiao, Fei Lv, Zhentao Cui, Qidi Xu
Summary: A simple and multi-layer metamaterial made of graphene is proposed to achieve excellent manipulation of the EIT-like effect. By adjusting the Fermi level of graphene, tunable EIT-like effect can be obtained. In addition, wideband EIT-like effect with high transmission can be achieved by adjusting the geometrical parameters of the metamaterial.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2022)
Article
Engineering, Electrical & Electronic
Tingting Lang, Zhenyu Yu, Jinhui Zhang, Zhi Hong, Jianjun Liu, Ping Wang
Summary: This study designs and theoretically analyzes a new type of sensor based on electromagnetically induced transparency metamaterials. The proposed metamaterial sensor consists of a polyimide substrate at the bottom and a periodic aluminum structure on the top. CST STUDIO SUITE is used to determine the transmission spectrum of the metamaterials in the terahertz band. The simulation results show that the sensitivity of the metamaterial sensor reaches 270.4 GHz/RIU. The metamaterial sensor is then fabricated to detect bovine serum albumin with a sensitivity of 15.390 GHz/(mg/mL) and a limit of detection (LOD) of 8.97 μg/mL in the concentration range of 0-10 mg/mL. The proposed sensor has the advantages of incident-angle insensitivity, polarization insensitivity, and small size, making it suitable for various research fields including physics, biology, and chemical sensing.
SENSORS AND ACTUATORS A-PHYSICAL
(2023)
Article
Nanoscience & Nanotechnology
Yuze Hu, Mingyu Tong, Siyang Hu, Weibao He, Xiang'ai Cheng, Tian Jiang
Summary: The study presents a dual-optically tunable metaphotonic device for ultrafast terahertz switching. It achieves picosecond ultrafast photoswitching with 100% modulation depth at either 0.55 THz or 0.86 THz, controlled by continuous wave light and femtosecond laser pulse. The technology enables frequency-selective, temporally tunable, and multidimensionally-driven features, making it valuable for advanced multiplexing of information and wireless communication.
Article
Physics, Condensed Matter
Renxia Ning, Dandan Guan, Yazhou Wang, Ningye He
Summary: A multiband tunable electromagnetic-induced transparency (EIT) effect can be obtained in the graphene metamaterials, with different resonance modes in the structure. The study is of great importance for U-band communication technology and switches.
EUROPEAN PHYSICAL JOURNAL B
(2023)
Article
Physics, Applied
Subhajit Karmakar, Ravi Varshney, Dibakar Roy Chowdhury
Summary: This study proposes enhancing effective responses in sub-skin depth metasurfaces through magneto-transport concept, and demonstrates dynamic magnetic modulation of structurally asymmetric metasurfaces in the terahertz domain. The introduction of magnetically reconfigurable ability in Fano resonant THz metamaterials improves their performances in the sub-skin depth regime.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2022)
Article
Optics
Tingling Lin, Yi Huang, Shuncong Zhong, Yujie Zhong, Zhenghao Zhang, Qiuming Zeng, Yingjie Yu, Zhike Peng
Summary: THz metamaterial sensing is an emerging technology in biomedical sciences with unique characteristics. This study reports an innovative method of manipulating the electric field to enhance liquid sensing at THz frequencies, which holds bright promises for real-time monitoring of trace biomolecules.
OPTICS AND LASERS IN ENGINEERING
(2022)
Article
Optics
Yuze Hu, Mingyu Tong, Zhongjie Xu, Xiangai Cheng, Tian Jiang
Summary: This study introduces a novel spatiotemporal metadevice for terahertz wave manipulation with ultra-high spatial and ultrafast temporal control, exhibiting bistability and erasable logic operations. By leveraging both spatial and temporal degrees of freedom, it lays the foundation for enhancing optical computing, data storage, and ultrahigh-speed information processing capabilities.
LASER & PHOTONICS REVIEWS
(2021)
Article
Optics
Rong LI, Zhenbi LI, Yuanyuan Jiang
Summary: This study presents a terahertz (THz) sensor based on a metasurface integrated with Au nanoparticles (AuNPs) to improve the sensitivity of whey protein detection and enhance the sensing index of group delay. It demonstrates that AuNPs can enhance the sensing performance of the biosensor. The internal mechanism is explained by modified perturbation theory and the coupled harmonic oscillator model. This study provides a method of enhancing the sensitivity of THz biosensors.
Article
Optics
Zhenqing Zhang, Fusheng Deng, Feng Wu, Chengjie Zhu
Summary: Researchers have developed a time-dependent theoretical approach to study the interaction between ultrashort terahertz pulses and metamaterials beyond the steady-state approximation. By using photoconductive silicon, they have shown that the system dispersion can be changed from abnormal to normal through classical interference effect. Consequently, terahertz pulses can propagate through the material with subluminal/superluminal group velocity. It has been demonstrated that predicting the propagation characteristics of terahertz pulses using steady-state solutions is inaccurate, and high-order dispersion terms play a significant role in pulse shape deformation and position-dependent group velocity modification. This theoretical approach is essential for describing the propagation properties of terahertz pulses in metamaterials and helps understand the nature of quantum interference in electromagnetically induced transparency metamaterials.
LASER PHYSICS LETTERS
(2022)
Article
Optics
Jin Leng, Jun Peng, An Jin, Duo Cao, Dejun Liu, Xiaoyong He, Fangting Lin, Feng Liu
Summary: The study found that changes in asymmetry significantly impact the Q factor and depth of amplitude modulation of Fano resonance, the carrier concentration of silicon plays a significant role in the intensity of excited Fano resonance, and a uniform graphene layer can effectively modulate Fano resonance.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Chemistry, Physical
Jin Zhang, Zhenfei Li, Linda Shao, Fajun Xiao, Weiren Zhu
Summary: The study demonstrates the active modulation of EIT analog by integrating graphene into a microwave metamaterial for the first time, showing that the EIT peak can be dynamically controlled under a relatively low bias voltage applied on graphene. The continuous tuning of the EIT resonance strength is achieved by variably dampening the dark resonator using graphene.
Article
Materials Science, Multidisciplinary
Xi Feng, Xieyu Chen, Yongchang Lu, Qingwei Wang, Li Niu, Quan Xu, Xueqian Zhang, Jiaguang Han, Weili Zhang
Summary: This paper proposes and experimentally demonstrates a new method for directly emitting focused THz vortex beams with desired orbital angular momentums. The method utilizes patterned ITO film to generate nonlinear THz emission, achieving effective integration of THz emission and vortex-beam generation.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Optics
Xiaolin Zhuang, Wei Zhang, Kemeng Wang, Yangfan Gu, Youwen An, Xueqian Zhang, Jianqiang Gu, Dan Luo, Jiaguang Han, Weili Zhang
Summary: A C-shape-split-ring-based phase discontinuity metasurface with a liquid crystal elastomer substrate is introduced for infrared modulation of terahertz wavefront. By manipulating the deflection of the substrate, controllable and broadband wavefront steering is achieved, with a maximum output angle change of 22 degrees at 0.68 THz. The liquid crystal elastomer metasurface also demonstrates the performance of a beam steerer, frequency modulator, and tunable beam splitter, which are highly desired in terahertz wireless communication and imaging systems.
LIGHT-SCIENCE & APPLICATIONS
(2023)
Article
Optics
Fan Huang, Quan Xu, Wanying Liu, Tong Wu, Jianqiang Gu, Jiaguang Han, Weili Zhang
Summary: A method for generating superposed optical vortices in the terahertz frequency range with orthogonal circular polarization incidences is proposed and demonstrated. This method provides opportunities for developing ultracompact terahertz functional devices.
PHOTONICS RESEARCH
(2023)
Article
Chemistry, Multidisciplinary
Qingwei Wang, Xueqian Zhang, Quan Xu, Xi Feng, Yongchang Lu, Li Niu, Xieyu Chen, Eric Plum, Jianqiang Gu, Quanlong Yang, Ming Fang, Zhixiang Huang, Shuang Zhang, Jiaguang Han, Weili Zhang
Summary: Coupling between different meta-atoms within the unit-cell can be used to control nonlinear THz generation, where achiral coupling provides control over THz field amplitude and chiral coupling makes THz generation sensitive to pump polarization. Multiplexed pump-handedness-selective nonlinear metasurfaces can be realized, allowing for the generation of THz beams with different orbital angular momentum. This approach enables the development of various integrated nonlinear THz devices.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Yi Xu, Jianqiang Gu, Yufei Gao, Quanlong Yang, Wanying Liu, Zhibo Yao, Quan Xu, Jiaguang Han, Weili Zhang
Summary: This study presents a novel meta-atom scheme using a silicon-silica-silicon sandwich-shaped structure, which enlarges the propagation phase and improves the dispersion engineering capability at low losses. An achromatic metalens is constructed using these meta-atoms, which exhibits remarkable achromatic focusing performance in the THz domain. This research not only demonstrates an outstanding terahertz achromatic metalens but also provides innovative ideas for constructing achromatic metasurfaces in various applications, beyond the THz domain.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Physics, Applied
Jiajun Ma, Chunmei Ouyang, Yuting Yang, Hongyi Li, Li Niu, Xinyue Qian, Yi Liu, Bin Yang, Quan Xu, Yanfeng Li, Liyuan Liu, Zhen Tian, Jianqiang Gu, Jiaguang Han, Weili Zhang
Summary: Topological photonics has advanced from theoretical concept to practical applications, with valley topological photonic crystals being a key candidate for future functional devices. However, the design and arrangement limitations have hindered the exploration of multichannel valley topological beam splitters. In this study, we investigate and demonstrate the robustness of different domain walls in valley topological photonic crystals and present a highly integrated multichannel valley topological beam splitter. Compared to traditional beam splitters, it is more robust, compact, and offers higher integration and more output ports. This brings new opportunities for engineering the flow of light and designing miniaturized integrated photonic devices.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Physical
Guanxuan Guo, Xueqian Zhang, Li Niu, Tong Wu, Xieyu Chen, Quan Xu, Jiaguang Han, Weili Zhang
Summary: We propose a programmable graphene metasurface based on the quantum effect analogue, electromagnetically induced transparency, which enables continuous amplitude and phase tuning of cross-polarized transmission in the terahertz (THz) regime. This programmable scheme allows flexible control over the diffraction angles and focal lengths of the transmitted THz beams, providing new inspirations for THz programmable metasurface devices.
Article
Chemistry, Physical
Jiaqi Zhang, Yuyue Yan, Hongwei Zhao, Xudong Niu, Liyuan Liu, Chunmei Ouyang, Weili Zhang
Summary: The GHz and THz complex dielectric spectra of a polyethylene glycol dimethyl ether (2000 g/mol) aqueous solution were investigated. The reorientation relaxation of water in this type of macro-amphiphilic molecule solution can be well described by three Debye models: under-coordinated water, bulk-like water, and slow hydrating water. The reorientation relaxation timescales of bulk-like water and slow hydration water both increase with concentration. By calculating the experimental Kirkwood factors of bulk-like and slow hydrating water, the changes in their dipole moments were estimated. The estimated water molecule numbers of three water components around monomers also support the sorting of water components.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Optics
Xiaohan Jiang, Quan Xu, Yuanhao Lang, Wanying Liu, Xieyu Chen, Yuehong Xu, Hang Ren, Xibin Wang, Su Xu, Xueqian Zhang, Chunmei Ouyang, Zhen Tian, Jianqiang Gu, Jiaguang Han, Weili Zhang
Summary: Geometric phase metasurfaces, a branch of meta-optics, have gained significant attention in recent years. The concept has been extended to near-field regime for the control of surface plasmons (SPs) by rotating dipole sources. However, there are still puzzles and shortcomings, such as the explanation for the reported geometric phases equal to the rotation angle and twice the rotation angle of the dipole sources for SP controls, and the limited control strategies for a single wavelength. In this study, a rigorous derivation of SP excitation by circularly polarized illumination is performed, clarifying the rotation dependence and coordinate correlation of geometric phase control of SPs. Furthermore, a holographic approach is proposed to implement multiplexed geometric phase control, demonstrating the ability to couple and steer incident circular polarizations of different wavelengths and spin directions to specific SP focusing beams. This work paves the way for integrated and multiplexed SP devices.
LASER & PHOTONICS REVIEWS
(2023)
Article
Chemistry, Multidisciplinary
Patinharekandy Prabhathan, Kandammathe Valiyaveedu Sreekanth, Jinghua Teng, Ranjan Singh
Summary: This study proposes a novel approach to chalcogenide phase change material (PCM)-incorporated steganographic nano-optical coatings (SNOC) for optical steganography. The SNOC design combines a broad-band and a narrow-band absorber made up of PCMs to achieve tunable optical Fano resonance in the visible wavelength, which is a scalable platform for accessing the full-color range. The study demonstrates the dynamic tuning of the Fano resonance line width by switching the structural phase of PCM, providing high-purity colors. For steganography applications, the SNOC cavity layer is divided into an ultralow loss PCM and a high index dielectric material with identical optical thickness, enabling the fabrication of electrically tunable color pixels on a microheater device.
Article
Multidisciplinary Sciences
Wenhao Wang, Yogesh Kumar Srivastava, Thomas CaiWei Tan, Zhiming Wang, Ranjan Singh
Summary: Non-radiative bound states in the continuum (BICs) can create resonant cavities with confined electromagnetic energy and high-quality (Q) factors. By folding all guided modes into the light cone through periodic perturbation, BZF-BICs with ultrahigh Q factors can be achieved in a large, tunable momentum space. Unlike conventional BICs, BZF-BICs show perturbation-dependent dramatic enhancement of the Q factor throughout the momentum space and are robust against structural disorders.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Applied
Nikhil Navaratna, Yi Ji Tan, Abhishek Kumar, Manoj Gupta, Ranjan Singh
Summary: On-chip terahertz (THz) biosensors have potential for real-time, label-free, and noninvasive detection of proteins, DNA, and cancerous tissue. However, high absorption of THz waves by water necessitates evanescent field-based biosensing. A topological waveguide cavity system with topologically protected propagating interfacial modes is shown to enhance on-chip THz biosensing by accurately detecting minute frequency shifts over extended periods, facilitating real-time sensing and monitoring of biological matter.
APPLIED PHYSICS LETTERS
(2023)
Article
Multidisciplinary Sciences
Kandammathe Valiyaveedu Sreekanth, Jayakumar Perumal, U. S. Dinish, Patinharekandy Prabhathan, Yuanda Liu, Ranjan Singh, Malini Olivo, Jinghua Teng
Summary: The researchers present a scalable Tamm plasmon cavity using phase change material with large resonance tunability and demonstrated tunable SERS by matching the plasmonic resonance with the molecule absorption for sensitivity enhanced biosensing.
NATURE COMMUNICATIONS
(2023)
Article
Multidisciplinary Sciences
Ridong Jia, Sonu Kumar, Thomas Caiwei Tan, Abhishek Kumar, Yi Ji Tan, Manoj Gupta, Pascal Szriftgiser, Arokiaswami Alphones, Guillaume Ducournau, Ranjan Singh
Summary: This research presents a 100-Gbps topological wireless communication link using integrated photonic devices, addressing the challenge of momentum mismatch and achieving high gain and wide bandwidth. The valley-conserved silicon topological waveguide antenna enables active beam steering and represents a major milestone in the field of hybrid electronic-photonic-based topological wireless communications.
Article
Materials Science, Multidisciplinary
Min Zhang, Shoujun Zhang, Qingwei Wang, Yihan Xu, Liwen Jiang, Yuyue Yan, Jiao Li, Zhen Tian, Weili Zhang
Summary: An ultrathin, flexible terahertz metamaterial based on biogel has been developed to detect the transmission of terahertz waves through biomolecules in aqueous solutions. The metamaterial can detect glucose in water, human serum, and human sweat with high sensitivity and can be used for long-term management of diabetes as a wearable device.
ADVANCED MATERIALS TECHNOLOGIES
(2023)