Article
Nanoscience & Nanotechnology
Isaac O. Oguntoye, Siddharth Padmanabha, Max Hinkle, Thalia Koutsougeras, Adam J. Ollanik, Matthew D. Escarra
Summary: Efficient and dynamic light manipulation at small scale can be achieved through active optical metasurfaces, which offer compact design and low power consumption. In this study, a dynamically tunable metasurface based on vanadium dioxide is demonstrated, allowing independent control of amplitude and phase without mechanical parts. The nanofabrication of vanadium dioxide enables computationally predicted continuously tuned amplitude and phase modulation. Experimental results show stable intermediate states and repeated modulation without degradation, indicating the potential for reprogrammable optical functionality.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Engineering, Electrical & Electronic
Antonino Cala Lesina, Dominic Goodwill, Eric Bernier, Lora Ramunno, Pierre Berini
Summary: This study introduces a novel plasmonic pixel design for beam steering in LIDAR, with simulations predicting the control of reflection coefficient phase. The research also discusses the optical response mechanism, the impact of connectors, and strategies to maximize reflection coefficient magnitude and achieve dual-band operation.
IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS
(2021)
Article
Optics
Maryam Hesari-Shermeh, Bijan Abbasi-Arand, Mohammad Yazdi
Summary: The analysis and synthesis of metasurfaces at various wavelengths is crucial, with a focus on the impact of substrates. A new method based on independent studies of electromagnetic behavior and interactions of constituting nanoparticles is proposed for substrated metasurfaces. The method utilizes image theory to calculate interaction constant tensors, presenting a general and useful approach for design and analysis of substrated metasurfaces.
Article
Engineering, Electrical & Electronic
Jordan Dugan, Joao Guilherme Nizer Rahmeier, Tom J. Smy, Shulabh Gupta
Summary: A zero-thickness model is developed to simulate nonuniform spatially dispersive metasurfaces and is validated numerically. The extended generalized sheet transition conditions (GSTCs) are used to model nonuniform metasurfaces by approximating them as locally linear space-invariant (LSI). A semianalytical Floquet method is derived to predict scattered fields from periodically varying metasurfaces. The results show excellent agreement between the proposed methods and the simulation software HFSS, highlighting the importance of considering spatial dispersion in modeling scattered fields.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Engineering, Electrical & Electronic
Yvo L. C. de Jong
Summary: This article presents a uniform ray description for electromagnetic wave scattering by locally periodic metasurfaces of polygonal shape. The model is derived by evaluating the critical-point contributions of a physical optics scattering integral and is valid for metasurfaces with periodic bulk scattering coefficients. The scattered field is expressed in terms of reflected, transmitted, and diffracted rays that do not necessarily obey conventional geometrical constraints.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Computer Science, Information Systems
Vitaly Kirillov, Dmitry Kozlov, Pawel Rulikowski, Senad Bulja
Summary: This paper presents a new beamforming network that adaptively distributes an input RF signal among a given number of antenna elements. The distribution of power and phase is achieved through a novel coupler design and active elements such as varactor diodes. A feeder network for a 16-element antenna array operating at 2.5 GHz is designed, simulated, and fabricated to demonstrate the proposed concept. The results show unprecedented reconfigurability in dividing the input signal among the antenna elements with arbitrary magnitudes and phases.
Article
Physics, Applied
Yugan Tang, Ya Zhang, Boyang Xie, Hua Cheng, Jianguo Tian, Shuqi Chen
Summary: This study demonstrates the possibility of controlling transmitted and reflected acoustic wavefronts in a decoupled manner using a passive structure. A transmission reflection-integrated (TRI) metasurface is designed to simultaneously realize multiple independent functions in the transmitted and reflected regions. Simulated, calculated, and experimental data confirm the efficient wavefront control and excellent functional-integration performance of the TRI metasurface. This research proposes a new approach to enhance the spatial utilization and functionality of acoustic devices.
PHYSICAL REVIEW APPLIED
(2022)
Article
Electrochemistry
Dieter Britz, Joerg Strutwolf, Ole Osterby
Summary: This paper simulates rectangular electrodes embedded in an insulating plane and estimates the steady diffusion limited currents for different relative lengths and widths. The behavior and steady state currents of square electrode arrays are also studied. The results show that the steady state currents of small arrays are lower than the theoretical values as the electrode separations increase.
ELECTROCHIMICA ACTA
(2022)
Article
Instruments & Instrumentation
Guangsheng Deng, Haisheng Mo, Zhifei Kou, Jun Yang, Ying Li, Zhiping Yin, Hongbo Lu
Summary: In this study, a novel interdigitated electrode architecture is explored to tune the permittivity of liquid crystal in metasurfaces with rapid responses. By adjusting the bias voltages through the grids, the orientation of liquid crystal molecules can be controlled, allowing arbitrary tuning of permittivity and electromagnetic responses. Different interdigitated electrodes were developed and their response time and frequency tunability were analyzed. The fill density of comb grids has a negligible effect on frequency tunability but significantly affects the response time. The proposed architecture and design provide new insights for developing tunable LC metasurfaces with rapid responses.
INFRARED PHYSICS & TECHNOLOGY
(2023)
Article
Engineering, Electrical & Electronic
Garima Joshi, R. Vijaya
Summary: A single-layer, all-dielectric, miniaturized metasurface for the terahertz range is designed and analyzed. It exhibits dual passbands at 164.20 and 257.56 GHz, with a wide stop band between them. By cascading two identical layers with a variably small air gap, continuous tunability and high passband selectivity over 100-300 GHz is achieved. The structure also shows invariance towards in-plane rotation and shift, providing freedom from misalignment errors.
OPTICAL AND QUANTUM ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Wenbin Feng, Mao Ye
Summary: A design method for a liquid crystal lens with adjustable positive-negative focal length and rectangular aperture is proposed. The designed electrodes create a parabolic profile of voltage difference over the lens aperture, enabling the realization of high-quality liquid crystal lens.
IEEE PHOTONICS TECHNOLOGY LETTERS
(2022)
Article
Engineering, Electrical & Electronic
Yunfei Fang, Shengqi Zhu, Yongchan Gao, Lan Lan, Cao Zeng, Zhixin Liu
Summary: This paper proposes a DOA estimation method for uniform linear antenna arrays with mutual coupling in the presence of unknown nonuniform noise. The method can handle both mixed and purely coherent signal scenarios. It eliminates nonuniform noise using the least squares criterion and adopts a middle subarray scheme to mitigate the influence of mutual coupling. Moreover, it derives a new strategy to directly determine DOAs without considering mutual coupling and performing spectral search, which improves the estimation accuracy and computational cost.
IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Zhe Zhang, Fangqing Wen, Junpeng Shi, Jin He, Trieu-Kien Truong
Summary: This letter proposes a method to estimate the 2-D direction-of-arrival (DOA) using a polarized uniform rectangular array (URA) under multipath propagation. The method establishes a parallel factor (PARAFAC) model that incorporates spatial response matrices, a polarization response matrix, and a source matrix. By taking the KhatriRao product with a full column rank factor matrix, the rank-deficiency of the source matrix is resolved, and three rearranged PARAFAC tensors are obtained. The estimation of 2D-DOA is then performed using the vector cross product-auxiliary rotational invariance technique (VCPARIT), which shows superiority over existing smoothing methods in terms of estimation accuracy.
IEEE SIGNAL PROCESSING LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Ruirui Bo, Shuanggen Zhang, Shuang Pi, Shumin Wang
Summary: In this paper, a plasmonic Talbot imaging scheme based on periodic metal nanopore arrays is proposed, and its tunable and self-healing performance is evaluated using the FDTD method. The results show that the transverse field distribution at the Talbot planes can be offset in the range of 500 nm by changing the incident light angle, demonstrating the tunability of spatial position. Additionally, the randomly missing and misaligned defects of such arrays can be effectively restored by the presence of low density or defects located at the center. The feasibility of spatial tunability and self-healing may have applications in optical imaging, nanolithography, and phase manipulation.
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Amirmasoud Ohadi, George V. Eleftheriades
Summary: This paper presents the theory, design, and implementation of a continuously tunable phase shifter using a surface-wave structure. The phase shifter operates at X-band from 8.5 to 10 GHz, providing 464 degrees phase shift with a figure of merit of 110 degrees/dB at 9.16 GHz. The proposed phase shifter can be used in phased arrays requiring high radiation efficiency at relatively high frequencies.
IEEE JOURNAL OF MICROWAVES
(2021)
Article
Optics
Zhaojian Zhang, Junbo Yang, Te Du, Hansi Ma, Xinpeng Jiang
Summary: In this work, polarization-insensitive dual bound states in the continuum (BICs) at the Gamma point in symmetric photonic crystal slabs are investigated. The BICs are tailored by adjusting the optical coupling strengths of the slabs. The transition from BIC to quasi-BIC resonances is realized using four different approaches while maintaining the slabs' symmetry. The resonances are found to be lowest-order eigenmodes that match the symmetry of incident plane waves, and their quality factors follow a specific law. Additionally, the dominant modes of the BICs are identified using multipolar decomposition. Anisotropic coupling adjustment is discussed, providing more control over the BICs. The work introduces a new perspective for manipulating BICs in PhC slabs and has potential applications in nonlinear enhancement and sensing.
Article
Optics
Siyang Xiao, Fen Zhao, Dongying Wang, Junjie Weng, Yan Wang, Xin He, Huan Chen, Zhaojian Zhang, Yang Yu, Zhenfu Zhang, Zhenrong Zhang, Junbo Yang
Summary: In this study, a double-process genetic algorithm (DPGA) optimization is proposed to inverse design metalens with extended depth of focus (EDOF), aiming to address the drawbacks of existing designs. By adopting different mutation operators, DPGA shows significant advantages in searching for the ideal solution and achieves improved depth of focus and stable imaging quality.
Article
Engineering, Electrical & Electronic
Junjie Weng, Yang Yu, Jianfa Zhang, Dongying Wang, Zhechun Lu, Zhencheng Wang, Jianqiao Liang, Shumao Zhang, Xiangcheng Li, Yang Lu, Zhou Meng, Junbo Yang, Zhenrong Zhang
Summary: In this paper, a biomimetic optical skin (BOS) based on optical microfiber coupler neuron (OMCN) is proposed, which realizes multimodal tactile perception for the first time. BOS can sensitively detect temperature, contact force, vibration, and recognize the hardness and roughness of objects through human-like tactile sensing. Furthermore, the excellent repeatability and stability of BOS are investigated, laying the foundation for practical applications.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2023)
Article
Optics
Hansi Ma, Te Du, Xinpeng Jiang, Zheng Peng, Wei Cheng, Yiyi Zhang, Xueling Wei, Zhaojian Zhang, Xin He, Zhenfu Zhang, Yang Yu, Yunxin Han, Huan Chen, Yuanxi Peng, Liang Fang, Junbo Yang
Summary: The three-dimensional mode division multiplexing (MDM) technology can assemble simple devices in the 3D space to extend the data capacity of photonic integrated circuits. In this study, a 16x16 3D MDM system with a compact footprint was proposed, which can achieve 256 mode routes by converting input waveguide modes into desired output waveguide modes. The simulated results show low insertion losses and cross talk levels for the system. The 3D design architecture can be scaled to achieve arbitrary network complexity levels.
Article
Optics
Jianqiao Liang, Yang Yu, Qiang Bian, Wenjie Xu, Zhencheng Wang, Shumao Zhang, Junjie Weng, Jiajian Zhu, Yong Chen, Xiaoyang Hu, Junbo Yang, Zhenrong Zhang
Summary: Metal coatings can protect optical fiber sensors and extend their lifespan in harsh environments. A nickel-coated fiber Bragg grating combined with an air bubble cavity Fabry-Perot interferometer fiber optic sensor was developed for simultaneous high-temperature and strain sensing. The sensor demonstrated successful testing at 545 degrees C for 0-1000 microstrain, and the characteristic matrix was used to separate temperature and strain. With its ability to attach to high-temperature metal surfaces, the metal-coated optical fiber sensor has potential applications in real-world structural health monitoring.
Article
Materials Science, Multidisciplinary
Dingbo Chen, Junbo Yang, Xin He, Yang Yu, Zhenfu Zhang, Huan Chen, Zhaojian Zhang, Zhongqi Tan, Hui Luo
Summary: This paper proposes a series of ultrathin OAM-tunable polarization-preserving vortex beam generators based on graphene metasurfaces, which can generate vortex beams with variable topological charges at terahertz frequency. By introducing diagonal cross-shaped graphene structures, the phase shift range for linearly polarized incident light can reach 2π while maintaining the original polarization state. Additionally, planar spiral phase generators are theoretically constructed to convert beams with plane wavefront into beams with spiral phase. The topological charges of the generated vortex beams can be dynamically tuned by the graphene Fermi energy in a broadband frequency range from 4.5 to 5.5 THz. This work provides a simple technology for the generation of vortex beams and the flexible modulation of the topological charge, which would inspire the application potential of vortex beams.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Optics
Jian Chen, Xin Li, Yutai Chen, Zhaojian Zhang, Yang Yu, Xin He, Huan Chen, Junbo Yang, Zhenfu Zhang, Xiaopeng Yao
Summary: We examined the relationship between the efficiency of the solar absorber and operating temperature and developed solar absorber devices with excellent performance. One of these devices has a solar spectral absorption of 95.6%, ultra-low emission rate of 5.7%, and optical-to-thermal conversion efficiency exceeding 90% under working temperatures of 600 K. It has the potential to surpass the Shockley-Queisser limit in solar power generation systems.
Article
Engineering, Electrical & Electronic
Qiang Bian, Hongtian Zhu, Jianqiao Liang, Yang Yu, Peiguang Yan
Summary: A mode field matching fusion splicing method between sapphire fiber and single-mode fiber was developed to solve the multimode issue, resulting in a quasi-single mode reflection spectrum from sapphire fiber Bragg grating. By optimizing the splicing parameters, a high-order modes suppression and a higher signal-to-noise ratio (SNR) were achieved. The improved fusion splicing method combined with a commercial single-mode interrogator enabled real-time temperature monitoring up to 1160 degrees C.
IEEE SENSORS JOURNAL
(2023)
Article
Optics
Hansi Ma, Xin He, Gangyi Zhu, Jiagui Wu, Xinpeng Jiang, Te Du, Zhaojian Zhang, Yaorong Wang, Linyi Wei, Shumao Zhang, Junjie Weng, Jie Huang, Yang Yu, Zhenfu Zhang, Yunxin Han, Huan Chen, Junbo Yang, Yuanxi Peng, Liang Fang
Summary: In this research, we developed a different-mode power splitter (WPS) using a novel multi-dimension direct-binary-search algorithm. The WPS is capable of generating multiple modes simultaneously with a balanced output. Compared to the traditional power splitter, the WPS has a shorter adiabatic taper length and exhibits lower insertion loss and crosstalk. Additionally, by utilizing tunable tap couplers, the WPS can be extended to multiple output ports with different modes and transmittances.
Article
Optics
Jie Nong, Xinpeng Jiang, Xueling Wei, Yiyi Zhang, Ning Li, Xin Li, Huan Chen, Xin He, Yang Yu, Zhenfu Zhang, Zhenrong Zhang, Junbo Yang
Summary: This study proposes an optically transparent metamaterial with multi-band compatible camouflage capability based on the inverse design. The metamaterial exhibits high transmittance, low reflectance, high emissivity, and insensitivity to incident light and polarization.
Article
Optics
Hansi Ma, Te Du, Xinpeng Jiang, Zhaojian Zhang, Xin He, Huan Chen, Yang Yu, Zhenfu Zhang, Yunxin Han, Junbo Yang, Yuanxi Peng, Liang Fang
Summary: In this study, we successfully designed three-channel and four-channel dual-mode waveguide crossings using the inverse design method. Based on highly-symmetric structures, the TE0 and TE1 modes are efficiently propagated through the crossings. The experimental results demonstrate low insertion losses and crosstalks of these devices.
Article
Optics
Shishang Luo, Zhenfu Zhang, Xin He, Zhaojian Zhang, Xin Li, Meicheng Fu, Junbo Yang
Summary: In this study, a reflective optical metasurface composed of a guided-mode resonance (GMR) filter and a phase-change material Sb2S3 is introduced to achieve tunable structural color. The combination of the GMR filter with narrow resonant wavelength and the Sb2S3 with larger bandgap and higher refractive index enables the production of high-quality tunable structural color. Simulation results demonstrate that the proposed metasurface can generate tunable structural color perceivable by the naked eye through the phase transition of Sb2S3 between amorphous and crystalline states. Furthermore, the metasurface can sensitively sense environmental changes through variations in structural color.
Article
Nanoscience & Nanotechnology
Xinpeng Jiang, Huan Yuan, Xin He, Te Du, Hansi Ma, Xin Li, Mingyu Luo, Zhaojian Zhang, Huan Chen, Yang Yu, Gangyi Zhu, Peiguang Yan, Jiagui Wu, Zhenfu Zhang, Junbo Yang
Summary: In this study, an experimental demonstration of a multilayer film structure (MFS) for infrared camouflage with thermal management is presented. By combining the ideal emission spectrum and genetic algorithm (GA), an optimized MFS with high performance of infrared camouflage and thermal management is designed.
