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Tunable terahertz focused vector vortex beam generation enabled by cascaded metasurfaces

Science China Physics, Mechanics & Astronomy 2025年第7期68卷 1-12页

作者： Li, Hui Nan, Tong Xu, Wenhui Li, Jie Zheng, Chenglong Tan, Qi Song, Chunyu Xu, Hang Zhang, Yan Yao, Jianquan Key Laboratory of Optoelectronics Information Technology Ministry of Education School of Precision Instruments and Opto-Electronics Engineering Tianjin University Tianjin China Beijing Key Laboratory for Metamaterials and Devices Key Laboratory of Terahertz Optoelectronics Ministry of Education Beijing Advanced Innovation Center for Imaging Technology Department of Physics Capital Normal University Beijing China Sichuan Meteorological Optoelectronic Sensor Technology and Application Engineering Research Center Chengdu University of Information Technology Chengdu China Key Laboratory of Material Physics Ministry of Education School of Physics and Microelectronics Zhengzhou University Zhengzhou China

Focused vector vortex beams (VVBs) offer significant potential for applications in nonlinear effects, quantum optics, and communications due to their symmetric intensity patterns, phase singularities, and structured polarization profiles. Nevertheless, the emerging frontier of dynamically tunable VVBs in the THz regime faces critical limitations in conventional static metasurface implementations, hindering their full potential for advanced photonic applications. In this work, we propose and demonstrate a design strategy, which employs dielectric cascaded metasurfaces to generate VVBs with tunable characteristics through mechanical twisting. To achieve this, Layer I is constructed from birefringent silicon pillars with rectangular configurations, enabling independent encoding of orthogonal circularly polarized channels via spin-decoupled phasing techniques, while Layer II is composed of cylindrical silicon pillars with polarization-maintaining properties to control the focal length. The generation and modulation of VVBs are achieved by mechanically adjusting the relative angles between these two layers, allowing for dynamic tuning of the beam’s properties. Experimentally, we further present the accurate generation of first- and second-order focused VVBs with a high focusing efficiency (> 12.9%), consistent with theoretical predictions. Moreover, the system exhibited continuous focal length tuning across 26λ−10.4λ by rotating the layers from 90° to 240°, achieving a 42.8% modulation depth, while maintaining radial symmetry, as confirmed by an absolute percentage error analysis (< 9.8%). The demonstrated mechanical tuning mechanism provides a practical pathway toward adaptive THz photonic devices, bridging critical gaps in real-world applications ranging from polarization-encoded communications to depth-resolved biomedical imaging.

关键词： all-silicon metasurface vector vortex beam spin-orbit interactions cascaded meta-device

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Liquid crystal between two distributed Bragg reflectors enables multispectral small-pitch spatial light modulator

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Light(Science & Applications) 2022年第8期11卷 1643-1645页

作者： Junghyun Park Kanghee Won Young Kim Advanced Sensor Lab Device Research CenterSamsung Advanced Institute of TechnologySuwonRepublic of Korea

The ability of controlling the phase of light at the subwavelength scale can be a game-changer due to its extraordinally wide angle-range in the wavefront shaping. By combining two conventional material and configurat... 详细信息

关键词： crystal enable light

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Magneto-optical conductivity and circular dichroism in d-wave altermagnets

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Physical Review B 2025年第6期111卷 064428-064428页

作者： Wang Chen Xiaoying Zhou Wen-Kai Lou Kai Chang State Key Laboratory of Semiconductor Physics and Chip Technologies Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 China College of Materials Science and Opto-electronic Technology University of Chinese Academy of Sciences Beijing 100049 China Hunan Provincial Key Laboratory of Intelligent Sensors and Advanced Sensor Materials School of Physics and Electronics Science Hunan University of Science and Technology Xiangtan 411201 China Center for Quantum Matter School of Physics Zhejiang University Hangzhou 310027 China

We theoretically investigate the Landau levels (LLs) and magneto-optical conductivity of a d-wave altermagnet under a perpendicular magnetic field. Our findings indicate that the LLs, in the absence of a Zeeman field and spin-orbit coupling (SOC), are spin-degenerate and exhibit a linear dependence on both the magnetic field and the level index. Within the framework of linear response theory, the analytical optical transition matrix elements yield isotropic selection rules and anisotropic longitudinal magneto-optical conductivity peaks, regardless of whether SOC is considered. Specifically, in the absence of SOC, only the intraband transition can occur, with the selection rule given by Δn=±1. The spin-resolved longitudinal magneto-optical conductivities without a Zeeman field alternately coincide (Reσxx↑=Reσyy↓ and Reσxx↓=Reσyy↑), resulting in identical spin-resolved Hall magneto-optical conductivities (Imσxy↑=Imσxy↓). In the presence of SOC, both intraband and interband transitions occur, with selection rules of Δn=±1 and ±3. Notably, the magnitude of the magneto-optical conductivities associated with the transition process of Δn=±1 is three orders of magnitude larger than that associated with Δn=±3. This distinctive magneto-optical absorption spectrum clearly reflects the structure of the LLs and leads to strong circular dichroism in the altermagnets. Our results elucidate the magneto-optical properties of altermagnets and can be utilized to determine band parameters at zero magnetic field.

关键词： Dichroism

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Dipole-induced transparency in a cavity-waveguide system with attractive cavity modes

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Physical Review A 2025年第3期111卷 033710-033710页

作者： Zhao-Hui Peng Chun-Xia Jia Yu-Qing Zhang Ying Yang Xiang-Yun Fu Wangjun Lu Le-Man Kuang Hunan Provincial Key Laboratory of Intelligent Sensors and Advanced Sensor Materials and Department of Physics Hunan University of Science and Technology Xiangtan 411201 China Department of Maths and Physics Hunan Institute of Engineering Xiangtan 411104 China Key Laboratory of Low-Dimension Quantum Structures and Quantum Control of Ministry of Education Synergetic Innovation Center for Quantum Effects and Applications and Department of Physics Hunan Normal University Changsha 410081 China Synergetic Innovation Academy for Quantum Science and Technology Zhengzhou University of Light Industry Zhengzhou 450002 China

Dipole-induced transparency (DIT) is one of the most well-known transparency effects in quantum optics and has wide applications in scalable quantum information processing and quantum computation. However, most of the existing literatures only focuses on the DIT effect with coherent dipole-cavity coupling, thus its universality in other types of coupling is still to be clarified. Here, we propose a feasible scheme to realize dissipative dipole-cavity coupling with the assistance of a highly dissipative microcavity, and explicitly exhibit cavity-mode attraction. We then investigate the DIT effect in a cavity-waveguide system with attractive cavity modes and find that it can still be achievable even though the probe light is resonant with two attractive cavity modes. Furthermore, we reveal its underlying transparency mechanism with eigenfrequencies and the effective susceptibility of the dipole-cavity system, and show that its transparency lies in the destructive interference of two attractive cavity modes with splitting damping rates instead of splitting resonance frequencies in coherent coupling. Moreover, we find that the attractive and repulsive phenomena of the effective susceptibility, which also plays an important role in the DIT effect, exist in the dipole-cavity system. Our findings may not only be of importance for gaining a more comprehensive understanding on the DIT effect, but also have potential applications in quantum networks.

关键词： Quantum optics

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Generalized Metasurface Design for Polarization Reconstruction in a Single Snapshot

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Journal of Lightwave technology 2025年

作者： Xu, Wenhui Li, Hui Liu, Yufei Li, Jie Tan, Qi Xu, Hang Zhang, Yan Yao, Jianquan Tianjin University Key Laboratory of Opto-Electronics Information Technology Ministry of Education School of Precision Instruments and Opto-Electronics Engineering Tianjin300072 China Capital Normal University Beijing Key Laboratory for Metamaterials and Devices Key Laboratory of Terahertz Optoelectronics Ministry of Education Beijing Advanced Innovation Center for Imaging Technology Department of Physics Beijing100048 China Chengdu University of Information Technology Sichuan Meteorological Optoelectronic Sensor Technology and Application Engineering Research Center Chengdu610225 China

Metasurfaces enable the design of compact devices that can detect polarization with high precision. This capability is highly significant in applications where space and weight are constraints, such as in portable sensors, optical systems, or communications. Nevertheless, traditional metasurface-based polarization measurement techniques may not work efficiently at terahertz (THz) frequencies due to the different behavior of THz waves compared to visible light. In this work, we propose and experimentally demonstrate a design strategy for THz polarization recognition that utilizes all-dielectric metasurface. This approach necessitated only the extraction of the electric field distribution at the focal plane in the transmission mode. The focal spot located at the center of the focal plane carries orbital angular momentum (OAM), which assisted in determining the azimuthal angle of the incident polarization state. Furthermore, off-axis focal spot positioned in four quadrants provided additional information regarding ellipticity and enable characterization of both axis ratio and the handedness of the polarization ellipse. The pivotal information delineated by the Stokes parameter S3, the axial ratio (AR), and ellipticity (χ) can effectively identify arbitrary polarization states that encompass the entire surface of Poincaré sphere. The consistency between the experimental and simulated results confirms the effectiveness of the designed metasurface in accurately reconstructing THz polarization states. The ability of the designed metasurface to manipulate and detect polarization states with high precision can improve performance in imaging, sensing, and communication systems. © 1983-2012 IEEE.

关键词： Spin polarization

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Real-Time Bird Counting and Environmental Control System for Enhanced Swiftlet Farmhouse Management

SSRN

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SSRN 2025年

作者： Markom, Arni Munira Rahman, Nuraishah Najiha Abdul Hamdan, Fakhirul Aziff Yusof, Yusrina Haris, Hazlihan Zaini, Muhammad Aizat Zaim Roslizar, Ahmad Muzammil Latiff, Anas Abdul Muhammad, Ahmad Razif Markom, Marni Azira School of Electrical Engineering College of Engineering Universiti Teknologi MARA Selangor Shah Alam40450 Malaysia Sabah Kota Kinabalu88400 Malaysia Hang Tuah Jaya Durian Tunggal Melaka76100 Malaysia Universiti Kebangsaan Malaysia UKM Selangor Bangi43600 Malaysia Faculty of Electronic Engineering & Technology Universiti Malaysia Perlis Kampus Pauh Putra Perlis Arau02600 Malaysia Center of Excellence for Advanced Sensor Technology Universiti Malaysia Perlis Kampus Pauh Putra Perlis Arau02600 Malaysia

This study presents the development of an IoT-based system for environmental monitoring and control, as well as bird counting, specifically designed for swiftlet farming in Menumbok, Sabah. The system integrates DHT11 and ultrasonic sensors to optimize habitat conditions and track swiftlet activity. Swiftlet farms face critical challenges in maintaining optimal environmental parameters and accurately monitoring bird populations, both essential for swiftlet health and productivity. The primary objective of this project is to establish a comprehensive system that not only monitors environmental factors but also allows farmers to actively control them, improving overall farm management. A key feature of this system is the ability to pump water from a barrel to a basin on the floor to regulate humidity levels, thereby enhancing the microenvironment for swiftlets. Two main methodologies were employed: (1) the installation of DHT11 sensors for continuous temperature and humidity measurement, ensuring optimal conditions for swiftlet habitation, and (2) the use of ultrasonic sensors at key entry points to accurately count swiftlets entering and exiting the farmhouse, providing precise data on their activity patterns. Key findings from the study include: (1) an average of approximately 600 swiftlets entered the farmhouse during peak evening hours (6 PM to 8 PM), while around 570 exited in the morning (5 AM to 7 AM), indicating stable population dynamics;(2) environmental data indicated temperature ranges from 31.9°C to 34.6°C, with humidity levels averaging 79%, which, while slightly below the optimal range, can be adjusted using the control system;and (3) variations in swiftlet activity were recorded, particularly increased movement during nighttime, suggesting external environmental influences on their behavior. In conclusion, this research demonstrates the effectiveness of integrating IoT technology for both environmental control and bird monitoring in swiftlet farming, o

关键词： Environmental monitoring

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Manipulating Piezoelectric and Electro-Strain Properties of BiFeO3-BaTiO3-Based Ceramics Through Chemical Doping-Controlled Domain-Size Engineering

SSRN

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SSRN 2025年

作者： Lin, Jiamin Liu, Bing Liu, Mengxiang Yang, Shan Zhou, Linming Hong, Zijian Zhu, Xiaoli Wu, Yongjun Li, Juan Huang, Yuhui School of Materials Science and Engineering State Key Laboratory of Silicon and Advanced Semiconductor Materials Cyrus Tang Center for Sensor Materials and Applications Institute of Fundamental and Transdisciplinary Research Zhejiang University Hangzhou310027 China Nanhu Brain-computer Interface Institute Zhejiang Hangzhou311100 China College of Electronic Information and Engineering Hangzhou Dianzi University Zhejiang Hangzhou310018 China Zhejiang Key Laboratory of Advanced Solid State Energy Storage Technology and Applications Taizhou Institute of Zhejiang University Zhejiang Taizhou318000 China School of Engineering Hangzhou City University Zhejiang Hangzhou310015 China College of Materials and Science Engineering Zhejiang University of Technology Zhejiang Hangzhou310006 China

Ferroelectric domains are crucial for the performance of piezoelectric ceramics, as the size and switching dynamics affect polarization response directly, manipulating both ferroelectric and piezoelectric properties. In this study, we achieved BiFeO3-BaTiO3 ceramics with domain sizes from macroscopic to nanoscale by incorporating a small amount of antiferroelectric phase. Contrary to the long-standing belief that smaller ferroelectric domains own lower polarization switching barriers and yield higher piezoelectricity, we found that in chemical doping-controlled domain size engineering, the smaller the domain size, the more difficult it is for polarization switching. Ceramics with the largest domain exhibited superior positive piezoelectric performance due to the sufficient polarization switching and reduced domain wall pinning, achieving a piezoelectric coefficient (d33) of 460 pC/N at 350°C. Middle-sized domains achieved optimal electro-strain performance determined by the trade-off between the domain walls pinning and the increased local tetragonal or orthorhombic symmetries, with a strain (0.29%) and an excellent piezoelectric strain coefficient (d33*) of 726.4 pm/V at 160°C. This work provides novel insights into how domain-size engineering affects domain switching and local distortion, offering guidance for performance optimization of piezoelectric ceramics. © 2025, The Authors. All rights reserved.

关键词： Piezoelectricity

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Passive diffusion of transdermal glucose: Noninvasive glucose sensing using a fluorescent glucose binding protein

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Journal of Diabetes Science and technology 2014年第2期8卷 291-298页

作者： Kanjananimmanont, Sunsanee Ge, Xudong Mupparapu, KarunaSri Rao, Govind Potts, Russell Tolosa, Leah Center for Advanced Sensor Technology University of Maryland Baltimore County Baltimore MD 21250 1000 Hilltop Circle United States

The motivation for this study was to determine if a statistically significant correlation exists between blood glucose (BG) and transdermal glucose (TG) collected by passive diffusion. A positive outcome will indicate that noninvasive passive TG diffusion is a painless alternative to collecting blood through a break on the skin. Sampling involves placing a small volume of buffer solution on the surface of membrane or skin for 5 minutes. The sample is then assayed with fluorescent GBP. In vitro testing was done on regenerated cellulose and a porcine skin model to determine diffusion of standard glucose solutions. In vivo testing was done on a healthy subject and a subject with type 2 diabetes. Glucose diffused readily through the regenerated cellulose membrane with good correlation between surface and internal glucose concentrations (R² = .997). But the porcine skin model required a surface prewash to achieve the same good correlation R² = .943). Based on this, an optimum prewash step was determined for the in vivo studies. The resulting correlation coefficients between TG and BG after a 15-minute prewash in a healthy subject and type 2 subject were .87 and .93, respectively. Removal of the extraneous glucose in the skin by prewashing was an important step in achieving good correlation between TG and BG. The results suggest that passive collection of TG is a noninvasive alternative to current practice of breaking the skin. Further studies are under way to determine the lag time between TG and BG and for the sampling protocol to be more amenable to point-of-care application. © 2014 Diabetes technology Society.

关键词： Fluorescent glucose binding protein Noninvasive glucose sensing

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Mobile Robot Based Simultaneous Localization and Mapping in UniMAP's Unknown Environment

Mobile Robot Based Simultaneous Localization and Mapping in ...

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2018 International Conference on Computational Approach in Smart Systems Design and Applications, ICASSDA 2018

作者： Syaqur, Wan Abdul Ali Yeon, Ahmad Shakaff Abdullah, Abu Hassan Kamarudin, Kamarulzaman Visvanathan, Retnam Ismail, Abdul Halim Mamduh, Syed Muhammad Zakaria, Ammar Universiti Malaysia Perlis Center of Excellence for Advanced Sensor Technology School of Mechatronic Engineering M-Arau Malaysia

ISBN: (纸本)9781538683699

Mapping is one of the most important aspect in robot navigation. This project emphasizes on the mapping using Simultaneous Localization and Mapping (SLAM) using GMapping approach. Turtlebot equipped with Hokuyo Laser Range Finder (LRF) URG-04LX-UG01 is used for the mapping. The SLAM operations were done in there different locations in UniMAP, which are either indoor or mixed of indoor-outdoor environment. The results show that the indoor maps obtained are more accurate than the outdoor map. This is due to the laser scanner unable to produce accurate scan measurement in outdoor environment and therefore result in scan matching problems. © 2018 IEEE.

关键词： Mapping

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Human 3D Reconstruction and Identification Using Kinect sensor

Human 3D Reconstruction and Identification Using Kinect Sens...

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2018 International Conference on Computational Approach in Smart Systems Design and Applications, ICASSDA 2018

作者： Lip, Chai Joon Yeon, Ahmad Shakaff Ali Kamarudin, Latifah Munirah Kamarudin, Kamarulzaman Visvanathan, Retnam Zaidi, Ahmad Firdaus Ahmad Mamduh, Syed Muhammad Zakaria, Ammar Nooriman, Wan Mohd Universiti Malaysia Perlis School of Mechatronic Engineering Center of Excellence for Advanced Sensor Technology M-Arau Malaysia

ISBN: (纸本)9781538683699

3D model of human body has been widely used in many applications including medical, health and security, since it is able to provide information on human body shape. This paper proposes a method to identify human based on the 3D model of the body and the depth data form the Kinect. The system firstly utilizes the coordinate points from the 3D model to calculate the selected anthropometry features of human body. Then, the features are compared with real time Kinect's depth acquisition to perform pose recognition and human identification. Eight candidates were involved in the reliability test of the system with each of them performed 6 trials, making a total of 48 trials. The overall reliability of the system in identifying the correct candidate was found to be 79.167%. © 2018 IEEE.

关键词： Image reconstruction

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