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Evaluation of occlusion immunities of free-space orbital angular momentum shift keying

Optics Express 2025年第6期33卷 13494-13505页

作者： Yang, Jinyu Zhang, Shurui Li, Lang Gao, Mingwei Gao, Chunqing Fu, Shiyao School of Optics and Photonics Beijing Institute of Technology Beijing100081 China Key Laboratory of Information Photonics Technology Ministry of Industry and Information Technology of the People’s Republic of China Beijing100081 China Key Laboratory of Photoelectronic Imaging Technology and System Ministry of Education of the People’s Republic of China Beijing100081 China National Key Laboratory on Near-Surface Detection Beijing100072 China

Orbital angular momentum (OAM) provides a new high-dimensional degree-of-freedom for lasers enabling high-dimensional shift keying, thus showing huge potential in free-space optical data-transmissions. Ensuring the accuracy of data transmission is of concern in any communication system. However, in the free-space OAM shift keying link, interferences from environmental occlusions will broaden the OAM spectrum and thus affect the correctness of information received. In this paper, the occlusion immunities of two commonly used OAM shift keying strategies—OAM-encoding-symbols and OAM-encoding-bits—are evaluated under different occlusion scenarios. We introduce radial, azimuthal, and random occlusions into the link and then analyze the bit error rate (BER) of various OAM shift keying strategies. The results illustrate that the strategy of OAM-encoding-symbols exhibits stronger occlusion immunity with zero BER than OAM-encoding-bits. Moreover, proof-of-concept experiments are done to transmit grayscale images under occlusions. The final decoding results show identical data-transmission performance with simulations. © 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

关键词： Bit error rate

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A Dual-band Broadband Conical Beam Antenna Based on TM and TM mode 31

A Dual-band Broadband Conical Beam Antenna Based on TM and T...

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31st Asia-Pacific Microwave Conference, APMC 2023

作者： Shan, Chuchu Zhang, Shuai Xue, Hui Wu, Li Rong, Yingjiao Nanjing University of Science and Technology School of Electronic and Optical Engineering Nanjing China Shanghai Radio Equipment Research Institute Shanghai China Science and Technology on Near Surface Detection Laboratory Wuxi China

ISBN: (纸本)9781665494182

A dual-band broadband conical beam antenna operating at Ku-/ Ka-band is presented in this paper. The proposed antenna adopts a novel across-layer folded structure which consists of two substrates. A circular patch with coupling slot is printed on the lower substrate as a monopole at Ku-band, and a circular patch and a loop patch are printed on the upper substrate to achieve operating at Ka-band. A wideband performance is obtained by introducing shorting vias to excite TM01 and TM02 mode in both bands. The simulation results show that the proposed antenna operates at 11.74 GHz-14.47 GHz in Ku-band and 32.20 GHz-35.63 GHz in Ka-band with 10 dB impedance bandwidth of 20.8% and 10.1%. And conical beam radiation patterns are achieved within the two bands, the peak gains in the lower and upper bands are 5.4 dBi and 9.9 dBi respectively. © 2023 IEEE.

关键词： conical beam dual-frequency microstrip patch antenna

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Selective formation of generalized optical skyrmions

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Optics Letters 2025年第9期50卷 2840-2843页

作者： Zhang, Haojun Gao, Chunqing Fu, Shiyao School of Optics and Photonics Beijing Institute of Technology Beijing100081 China Key Laboratory of Information Photonics Technology Ministry of Industry and Information Technology of the People’s Republic of China Beijing100081 China Key Laboratory of Photoelectronic Imaging Technology and System Ministry of Education of the People’s Republic of China Beijing100081 China National Key Laboratory on Near-Surface Detection Beijing100072 China

Optical skyrmions, a type of topologically protected quasiparticle, have undergone various deformations in recent years. In this Letter, we present a scheme that can achieve the selective formation of generalized optical skyrmions. In our proposal, a liquid-crystal spatial light modulator and a variable liquid-crystal retarder, both of which are commonly programmable devices, are employed, allowing for the on-demand precise manipulation of topological textures of various quasiparticles including but not limited to skyrmions, antiskyrmions, and bimerons. The proof-of-concept experiments illustrate that generalized optical skyrmions whose skyrmion number up to 5 can be well generated with on-demand tailored topological textures. While maintaining a simple setup, the system demonstrates a notable capacity for the manipulation of intricate high-order textures, signifying its considerable potential for extensive and sophisticated applications in the generation and manipulation of skyrmions. © 2025 Optica Publishing Group.

关键词： Topology

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Design and Verification of a Dielectric Laser Accelerator Test System for Sub-Relativistic Electrons 10

Design and Verification of a Dielectric Laser Accelerator Te...

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Nano-optoelectronics and Micro/Nano-photonics X 2024

作者： Chen, Ke Li, Dandan Liu, Ziyang Yang, Chenyi Lu, Bingheng Yang, Yadong Wang, Qianqian School of Optics and Photonics Beijing Institute of Technology Beijing100081 China National Key Laboratory on Near-surface Detection Beijing10072 China Key Laboratory of Photonic Information Technology Ministry of Industry and Information Technology Beijing100081 China

ISBN: (纸本)9781510682160

Dielectric laser accelerators (DLAs) can achieve acceleration gradients that are 1 to 2 orders of magnitude higher than traditional radiofrequency (RF) accelerators. Due to the micrometer-scale dimensions of the DLA acceleration structure, on the one hand, high requirements are imposed on the quality of the electron beam and the alignment among the electron beam, driving laser, and DLA in experiments. On the other hand, although the DLA acceleration gradient is very high, the acceleration distance is insufficient, resulting in relatively small absolute energy gain for sub-relativistic electrons after DLA acceleration. These electrons are susceptible to interference from stray electromagnetic fields during propagation, posing significant challenges to the resolution and accuracy of sub-relativistic electron energy spectrum testing. Based on the principle of laser-driven grating-structure DLA for accelerating electron beams, this paper designs a complete test system, constructs electronic dynamics simulation models and magnetic field measurement electron energy spectrum simulation models for verification, designs a double-layer magnetic shunt to shield the interference of leakage magnetic fields on electrons in the simulation, considers factors such as the beam spot radius, divergence angle, and geomagnetic field intensity of the electron beam that conform to experimental conditions, and finally obtains simulated images of electron spots on the fluorescent screen after the electron beam is deflected by the magnetic field. The electron dynamics simulation results show that the electron beam achieves a maximum energy gain of 14.4401 keV over an acceleration length of 36 μm, with an acceleration gradient reaching 401.114 MeV/m. Based on the acceleration effect, a magnetic field of BB = 170 Gs is set, and an electron spot after deflection is obtained. The edges of the spots before and after acceleration are separated by Δd = 4.2889 mm, and the maximum energy gain measurem

关键词： Fluorescent screens

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Ground penetrating radar target detection method based on optimized Faster RCNN and k-means clustering

Ground penetrating radar target detection method based on op...

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IET International Radar Conference 2023, IRC 2023

作者： Xin, Changle Lei, Wentai Luo, Chaopeng Xue, Wei School of Computer Science and Engineering Central South University Changsha China School of Electronic Information Central South University Changsha China Science and Technology on Near-Surface Detection Laboratory Wuxi China

ISBN: (纸本)9781839539954

Ground Penetrating Radar (GPR) technology is a widely used detection technology for underground target objects, which can perform non-destructive detection of underground targets. Due to the complexity of the underground environment and the interference of clutter, manual processing of GPR data is a time-consuming and laborious task. Therefore, an accurate and fast automatic underground target detection method is urgently needed. We propose a method that can achieve fast goals in complex multi-goal situations. The simplified ResNet-50 network is used to detect dense intersecting hyperbolic curves and reduce the computation of the network. At the same time, we use k-means clustering algorithm to optimize the anchor in faster-Rcnn based on the characteristics of GPR hyperbola. In addition, this method is also suitable for target detection on GPR images under random media. © The Institution of Engineering & technology 2023.

关键词： K-means clustering

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Temporal multiplexing coding strategy for spatiotemporal compressed imaging 4

Temporal multiplexing coding strategy for spatiotemporal com...

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4th International Computational Imaging Conference, CITA 2024

作者： Hao, Xiaowen Ke, Jun School of Optics and Photonics Beijing Institute of Technology Beijing100081 China Key Laboratory of Photo-electronic Imaging Technology and System Ministry of Education of China Beijing100081 China National Key Laboratory on Near-surface Detection Beijing100072 China

ISBN: (纸本)9781510688834

Spatiotemporal compressed imaging(STCI) aims to improve the spatial and temporal resolution of an imaging system simultaneously, which can effectively alleviate the mutual constraints between the two imaging resolutions. However, the development of STCI is limited by the effectively modulate target scenes in dual-domain, and by the back-end reconstruction process which doesn't work well for high compression ratio(CR). In this paper, we propose a temporal multiplexing coding strategy for STCI, which can effectively help the reconstruction algorithm for a large CR. Simulated experiments are implemented to demonstrate our idea. The proposed method can achieve nice spatiotemporal reconstructions with CR equal to 128:1, in which the spatial CR is 16:1 and the temporal CR is 8:1. © 2025 SPIE.

关键词： Image coding

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Optimizing object classification with single-pixel imaging and transformer networks 4

Optimizing object classification with single-pixel imaging a...

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4th International Computational Imaging Conference, CITA 2024

作者： Cheng, Yin Liao, Yusen Sun, Xin Ke, Jun School of Optics and Photonics Beijing Institute of Technology Beijing100081 China Key Laboratory of Photo-electronic Imaging Technology and System Ministry of Education of China Beijing100081 China National Key Laboratory on Near-surface Detection Beijing100072 China

ISBN: (纸本)9781510688834

Traditional computer vision tasks rely on high-quality images for classification, but single-pixel imaging (SPI) uses compressive sensing with a bucket detector to simplify hardware and reduce costs. However, factors like atmospheric turbulence can degrade SPI image quality, lowering classification accuracy. To address this, a block-based single-pixel image-free transformer classification framework is proposed. It uses a learnable binary sampling matrix for flexible sampling during SPI and divides the measurements into blocks, which are processed by a transformer network. Each block is treated as a sequence element, allowing the transformer to capture spatial and contextual relationships. Experiments show strong robustness to atmospheric turbulence, achieving 87% classification accuracy even at a 1% sampling rate, making this method suitable for challenging environments. © 2025 SPIE.

关键词： Pixels

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Depth map stitching using compound eye cameras for wide FOV imaging 10

Depth map stitching using compound eye cameras for wide FOV ...

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10th Symposium on Novel Optoelectronic detection technology and Applications

作者： Qiao, Zhibo Hao, Qun Li, Shibiao Cheng, Yang School of Optics and Photonics Beijing Institute of Technology Beijing100081 China National Key Laboratory on Near-Surface Detection Beijing100072 China Yangtze Delta Region Academy of Beijing Institute of Technology Jiaxing314003 China

ISBN: (数字)9781510688155

ISBN: (纸本)9781510688148

Depth information is an important tool in the computer vision field for object detection, recognition, and 3D modeling. Conventional depth sensors have a limited field of view(FOV) and provide limited depth information. Depth map stitching has been proposed to construct a large FOV image by combining depth maps from different perspectives. Due to the sparsity of features and susceptibility to lighting conditions in the depth images, stitching faces a challenge as it often relies on feature matching for obtaining mapping matrices. To overcome this issue, this paper proposes an algorithm that utilizes color image features to guide depth map stitching. Initially, the LightGlue algorithm based on SuperPoint features is employed for precise feature matching to obtain accurate homography matrices. Depth maps are then generated using stereo vision and aligned with color images, effectively transforming the depth map stitching challenge into a color image stitching task. Additionally, we designed a bionic compound eye imaging system that captures images in real time using multiple cameras. This system consists of eight cameras arranged in pairs at specific angles with a circular configuration, achieving an expanded FOV. Experimental results demonstrate that the system effectively captures depth maps with an FOV of 110°×90° and can display real-time video with 8 frames at 640 ×480 resolution. The maximum relative depth error is 5.7% @ 0.55m. In the future, this technology is expected to be applied in panoramic 3D reconstruction, underwater mapping, and autonomous driving. © 2025 SPIE.

关键词： Stereo image processing

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Optical simulation and imaging performance evaluation on the influencing parameters of the Alvarez lenses 10

Optical simulation and imaging performance evaluation on the...

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10th Symposium on Novel Optoelectronic detection technology and Applications

作者： Li, Chaohui Hao, Qun Liu, Lin Cheng, Yang School of Optics and Photonics Beijing Institute of Technology Beijing100081 China National Key Laboratory on Near-Surface Detection Beijing100072 China Yangtze Delta Region Academy of Beijing Institute of Technology Jiaxing314003 China

ISBN: (数字)9781510688155

ISBN: (纸本)9781510688148

Optical varifocal systems have extensive applications such as consumer electronics, defense equipment, industrial monitoring, and medical devices. Traditional varifocal methods typically involve multiple lenses and mechanical components. The lenses often move along the optical axis using motors to achieve the varifocal ability. This configuration introduces some limitations, such as more structural complexity, larger size, slower varifocal speed, and higher production cost. Different from the traditional varifocal lenses, Alvarez lenses comprise two symmetrically arranged freeform surface phase plates moving perpendicular to the optical axis. The Alvarez lenses achieve a wide varifocal range through small lateral displacement offering a compact design and a large varifocal range. Besides the parameter of lateral displacement, the varifocal range and the imaging performance of the Alvarez lenses are influenced by other parameters. This paper aims to explore and analyze how different parameters impact the imaging performance of Alvarez lenses. The analysis focuses on the two parameters, i.e., the vector height modulation coefficient(A), the tilt of the freeform surface (D), air gaps, and installation errors. Parameter A controls the height difference between peaks and valleys of the freeform surface and directly affects the varifocal capability of the Alvarez lenses. Through the optical simulation of the Alvarez lens via OpticStudio software, we found that a decrease in the value of parameter A helps to reduce the rate of performance degradation. However, the smaller value of the parameter A necessitates a larger lateral displacement to achieve equivalent changes in focal length. The increase in displacement results in higher power consumption and a slower response time. Thus, selecting an optimal A value and refining D are crucial to enhancing the Alvarez lenses's overall performance. To identify the optimized parameters, we simulated five different sets of the param

关键词： Ray tracing

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A UWB/IMU-Assisted Fingerprinting Localization Framework with Low Human Efforts

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China Communications 2024年第6期21卷 40-52页

作者： Pan Hao Chen Yu Qi Xiaogang Liu Meili School of Mathematics and Statistics Xidian UniversityXi’an 710126China Science and Technology on Near-Surface Detection Laboratory Wuxi 214035China School of Software Nanchang Hangkong UniversityNanchang 330063China

With the rapid development of smart phone,the location-based services(LBS)have received great attention in the past *** to the widespread use of WiFi and Bluetooth devices,Received Signal Strength Indication(RSSI)fingerprintbased localization method has obtained much development in both academia and *** this work,we introduce an efficient way to reduce the labor-intensive site survey process,which uses an UWB/IMU-assisted fingerprint construction(UAFC)and localization framework based on the principle of Automatic radio map generation scheme(ARMGS)is proposed to replace the traditional manual *** be specific,UWB devices are employed to estimate the coordinates when the collector is moved in a reference point(RP).An anchor self-localization method is investigated to further reduce manual measurement work in a wide and complex environment,which is also a grueling,time-consuming process that is lead to artificial ***,the measurements of IMU are incorporated into the UWB localization algorithm and improve the label accuracy in *** addition,the weighted k-nearest neighbor(WKNN)algorithm is applied to online localization ***,filed experiments are carried out and the results confirm the effectiveness of the proposed approach.

关键词： indoor localization machine learning ultra wideband WiFi fingerprint

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