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Multi Topological Charges Vortex Beam Generator Based on Nonlinear Bound States in the Continuum with Improvement of Nonlinear Conversion Efficiency

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SSRN 2023年

作者： Xu, Hang Li, Hui Tan, Qi Song, Chunyu Li, Mengyao Liu, Yanyan Zhang, Yating Wang, Bo Li, Jie Yao, Jianquan Ministry of Education School of Precision Instruments and Opto-Electronics Engineering Tianjin University Tianjin300072 China Function laboratory for Marine Fisheries Science and FoocProduction Processes Qingdao National LaboratoryTechnology Qingdao China Key Laboratory of Quantum Matt Science Henan Key Laboratory of Photovoltaic Materials Henan University KaifengHenan475004 China Information Materials and Device Applications Key Laboratory of Sichuan ProvincialUniversities Chengdu University of Information Technology 610225 China Science and Technology on Electro-Optical Information Security Control Laboratory Tianjin300308 China

In the momentum space of bound states in the continuum (BIC), vortex configurations around the Γ-point are generated by the selection rules. The electric field distribution close to the BIC satisfies twofold rotational symmetry (C2). Since the periodic structure of 2D photonic crystals (PhCs) supports the generation of odd harmonics, this characteristic provides an attractive approach for generating high-harmonic optical vortex (OV) beams with both left and right handedness. Also, the topological charge of OV beams generated by C4v-symmetric PhCs can be further improved by an increase of structural symmetry. Moreover, since the nonlinear conversion efficiency of directly used PhCs is low, their practicability is limited. Here, a hexagonal arrangement of C6v-symmetric 2D PhCs slab is selected. Through energy band selection, higher order fundamental and nonlinear OV beams can be generated, which can not only cover the topological charge of the C4v-symmetric structure, but also generate more abundant topological charge. In addition, we improve the third-order nonlinear conversion efficiency by the mirror approach, which is 22 times greater than with the direct use of PhCs. This method can improve the channel capacity of OV generators based on BICs and make them more practical. © 2023, The Authors. All rights reserved.

关键词： Conversion efficiency

Reconfigurable Metagrating Enabled by Shape Memory Polymers

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Reconfigurable Metagrating Enabled by Shape Memory Polymers

IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWS-AMP)

作者： Sidi Wang Kai Feng Jianjia Yi Key Laboratory of Integrated Services Network Xidian University Xi’an China Science and Technology on Electro-Optical Information Security Control Laboratory Tianjin China School of Information and Communications Engineering Xi’an Jiaotong University Xi’an China State Key Laboratory of Millimeter Waves Southeast University Nanjing China

We propose and demonstrate a shape-controlled metagrating with adjustable energy distribution based on shape memory Polymers (SMPs). The design consists of a capacitance printed on the top of the FR4 substrate, SMPs substrate (VeroWhitePlus) in the middle layer, and a metallic ground at the bottom. Using the perfect diffraction theory to design reconfigurable metagratings based on shape memory polymers is. Furthermore, the functionalities of the designed shape-controlled tunable metagrating are investigated by full-wave simulations. Simulation results show that the reconfigurable metagrating can achieve energy bisection of +1, -1 order and the energy trisection of +1, 0, -1 order. And the proposed reconfigurable metagrating is experimentally demonstrated. The design breaks through the limitation that the traditional electrically tunable reconfigurable metagratings need external power supply, and provides a new design idea for the dynamic control of energy distribution of the reconfigurable metagratings.

关键词： Radio frequency Shape Diffraction Simulation Switched mode power supplies Process control Holography

Fast Fourier single-pixel imaging based on Sierra–Lite dithering algorithm

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Chinese Physics B 2019年第6期28卷 189-194页

作者： Zhen-Yu Liang Zheng-Dong Cheng Yan-Yan Liu Kuai-Kuai Yu Yang-Di Hu National University of Defense Technology State Key Laboratory of Pulsed Power Laser TechnologyHefei 230037China Science and Technology on Electro-Optical Information Security Control Laboratory Tianjin 300000China

The single-pixel imaging(SPI) technique is able to capture two-dimensional(2 D) images without conventional array sensors by using a photodiode. As a novel scheme, Fourier single-pixel imaging(FSI) has been proven capable of reconstructing high-quality images. Due to the fact that the Fourier basis patterns(also known as grayscale sinusoidal patterns)cannot be well displayed on the digital micromirror device(DMD), a fast FSI system is proposed to solve this problem by binarizing Fourier pattern through a dithering algorithm. However, the traditional dithering algorithm leads to low quality as the extra noise is inevitably induced in the reconstructed images. In this paper, we report a better dithering algorithm to binarize Fourier pattern, which utilizes the Sierra–Lite kernel function by a serpentine scanning method. Numerical simulation and experiment demonstrate that the proposed algorithm is able to achieve higher quality under different sampling ratios.

关键词： single-pixel imaging binary Fourier basis pattern the dithering algorithm

Explore a Novel Knowledge Distillation Framework for Network Learning and Low-Bit Quantization

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Explore a Novel Knowledge Distillation Framework for Network...

Chinese Automation Congress (CAC)

作者： Liang Si Yuhai Li Hengyi Zhou Jiahua Liang Longjun Liu Institute of Artificial Intelligence and Robotics (IAIR) Xi’an Jiaotong University Xi’an China Key Laboratory of Electro-Optical Information Control and Security Technology Tianjin China

ISBN: (纸本)9781665426480

Knowledge distillation is a kind of model compression methods. It improves the performance of "student" networks by transferring the knowledge of "teacher" to "student". However, due to the huge gap between "teacher" and "student" in knowledge representation capabilities, directly minimizing the difference between them to transfer the knowledge will lead to the convergence issue. To this end, this paper proposes a novel framework of knowledge distillation. By sharing the weights of "teacher" and "student" in fully connected layers, we reduce the challenge of knowledge transfer. Furthermore, we propose a novel training strategy to improve the performance of low-bit quantization networks based on our distillation framework called distillation for low-bit quantization (DLBQ). The experimental results show that our methods can achieve significant improvement across different tasks. For instance, ResNet-20 gains 1.81% improvement on Cifar10 dataset. ResNet-56 shows 3.36% improvement on Cifar100 dataset and even exhibits 1.72% performance improvement than "teacher" network. Additionally, as for the improvements of quantization performance, ResNet-20 gain 1.25% improvement with ternary weights on Cifar10, and ResNet-110 manifects 3.22% improvement with binary weights on Cifar100 dataset.

关键词： Knowledge engineering Training Multiprotocol label switching Quantization (signal) Automation Knowledge representation Task analysis

Design and Implementation of Infrared Image Preprocessing System based on FPGA

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Design and Implementation of Infrared Image Preprocessing Sy...

Chinese Automation Congress (CAC)

作者： Lankun Li Wancheng Liu Ruiqi Lei Longjun Liu Institute of Artificial Intelligence and Robotics (IAIR) Xi’an Jiaotong University Xi’an China Key Laboratory of Electro-Optical Information Control and Security Technology Tianjin China

ISBN: (纸本)9781665426480

Infrared image processing is a conventional topic, but the hardware design and implementation for infrared image processing algorithms are full of challanges, especially for special purpose infrared detectors which have customized interfaces and protocols. Moreover, some customized infrared detectors only generate the infrared image with very poor quality. Therefore, in this paper, we design and implement an infrared image preprocessing system based on FPGA for customized infrared detectors. We propose a hardware architecture that includes the whole process from the input of detector, image processing, to final infrared video stream output and display. Our hardware architecture is able to adapt to different customized infrared detectors, which has the characteristics of real-time, low-power, dynamic parameter configuration, high processing efficiency and stable imaging effect. We have implemented it on Xilinx FPGA. The infrared imaging effect is significantly improved with limited FPGA resources (about only 1.6M LUT, 420 BRAM for all algorithm models on Xilinx zc706 evaluation board), the image processing speed can reach to 225Hz with the resolution of 320*256. Our preprocessing system can generate real-time video for display with 1920*1080@60Hz.

关键词： Infrared detectors Protocols Image resolution Detectors Infrared imaging Streaming media Hardware

Raman Spectra, Chemical Bonds And Dielectric Properties of Calanbwo 8 Ceramics

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SSRN 2024年

作者： Li, Yingxiang Liu, Wei Pang, Xianying Xiao, Lei Oad, Ammar Peng, Sen Liang, Deyin Tang, Bin Fang, Zixuan Shi, Zitao Chen, Jingjing Wang, Fei He, Chuansheng Hou, Zegui Liu, Weichun Sun, Yuxin Xue, Yan Li, Hao College of Information Engineering Shaoyang University Shaoyang422000 China State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China Chengdu611731 China School of Civil Engineering and Geomatics Southwest Petroleum University Chengdu610500 China College of Electrical and Information Engineering Hunan University Changsha410082 China Science and Technology on Electro-Optical Information Security Control Laboratory Tianjin300308 China Southwest Jiaotong University Hope College Chengdu610000 China School of Electronic and Communication Engineering Shenzhen Polytechnic Shenzhen518055 China

A novel CaLaNbWO8 (CLNWO) ceramic was prepared using traditional solid-state methods. The CLNWO ceramics that were sintered at 1440°C displayed noteworthy dielectric properties, with Εr = 11.18, Q×f = 32,998 GHz, and τf = −8.1 ppm/°C. The trends in Εr and Q×f were indirectly reflected through the Raman shift and FWHM in Raman spectroscopy. Through bond valence analysis, it was determined that Ca2+ and La3+ have significant compression effects in CLNWO ceramics, and the αc was less than αtheo. This discrepancy resulted in the Εr of CLNWO ceramics being less than Εtheo. According to Phillips-Vechten-Levine (P-V-L) theory, the W-O bond primarily determined τf, and Q×f, whereas Εr was noticeably influenced by the La-O bond. © 2024, The Authors. All rights reserved.

关键词： Raman scattering

Laser Induced Nano-Hole for High Throughput Fabrication of Silver Doped Chalcogenide Metasurfaces

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SSRN 2022年

作者： Zhou, Jianhong Zhao, Jianxing Cao, Lixiao Zhou, Yao Wang, Li Wang, Chonge Jing, Wenbo Zhang, Gong Yu, Ying School of Photoelectric Engineering Changchun University of Science and Technology Changchun130022 China Science and Technology on Electro-Optical Information Security Control Laboratory China Electronics Technology Group Corporation 53rd Research Institute Tianjin300308 China

We report the potential method for high throughput chalcogenide metasurface fabrication by using focused 632.8 nm laser induced nano-hole effect in the silver doped Ge28Sb12Se60 film. Generally, laser induced dewetting effect is hard to realize in thin Ge28Sb12Se60 films, however with the assistance of silver doping, the randomly distributed nano holes can be acquired in the dewetted region. The higher the silver concentration, the easier the laser induced nano-hole effect is, but much higher silver concentration like 47.8% will suppress the laser induced nano-hole effect due to the photocrystallisation. The nano holes can be enlarged and further connect with adjacent ones by increasing the output laser power, thus the morphology of the laser induced nano holes can be flexibly manipulated. Our findings are beneficial in high-throughput fabrication of chalcogenide metamaterial. © 2022, The Authors. All rights reserved.

关键词： Silver

Metasurfaces with high-Q resonances governed by topological edge state

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Optics letters 2022年第7期47卷 1822-1825页

作者： Zhidong Gu Jiaxin Chen Bofeng Gao Wei Wu Zhenyu Zhao Wei Cai Xinzheng Zhang Mengxin Ren Jingjun Xu The Key Laboratory of Weak-Light Nonlinear Photonics Ministry of Education School of Physics and TEDA Applied Physics Institute Nankai University Tianjin 300071 China Science and Technology on Electro-Optical Information Security Control Laboratory Tianjin 300308 China Department of Physics Shanghai Normal University Shanghai 200234 China e-mail: weicai@*** e-mail: jjxu@***

Achieving high-quality (Q)-factor resonances in metasurfaces is essential for various applications, including nano-lasers, nonlinear optics, and quantum optics. In this work, we propose a high-Q metasurface using a topological strategy: constructing the metasurface by stacking two conjugated nanopillar arrays with different topological invariants. Our study shows that a topological edge state steadily appears at the interfaces of the nanopillars, and a sharp transmission resonance with a Q-factor of more than 1000 can be obtained. The sensing application of such high-Q topological metasurface is also demonstrated, whose figure of merit reaches approximately 145. The proposed strategy and underlying theory can open up new avenues to realize ultrasharp resonances, which can promote numerous potential applications, such as biosensing, optical modulation, and slow-light devices.

关键词： electromagnetically induced transparency Nonlinear optics optical systems Quantum optics Refractive index Resonance

Efficient Multi-Stage Network with Pixel-Wise Degradation Prediction for Real-Time Motion Deblurring

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SSRN 2022年

作者： Hao, Zeyu Wang, Hang Zhang, Xuchong Li, Yuhai Sun, Hongbin Institute of Artificial Intelligence and Robotics Xi’an Jiaotong University Shaanxi Xi’an710049 China School of Microelectronics Xi’an JiaoTong University Shaanxi Xi’an710049 China Science and Technology on Electro-Optical Information Security Control Laboratory Tianjin300308 China

Motion deblurring is an indispensable task in perceptual systems because motion blur can seriously influence the visual effect and the quality of subsequent perception tasks. In practical application, efficiency and effect of motion deblurring are both important. However, among the existing methods, there is no design that can meet the real-time and visual quality requirements at the same time. Thus, an efficient motion deblurring network is proposed by leveraging multi-stage pixel-wise degradation prediction. Specifically, some lightweight modules are designed to accelerate processing while attention and multi-scale mechanism are introduced to maintain quality. In addition, a pixel-wise degradation prediction module and a spatial-channel compensation module are further employed to improve the deblurring quality, such as the distortion of moving objects in the restoration images. Extensive experimental results show that the proposed network can achieve the same PSNR level as the SOTA lightweight deblurring methods and is far faster (5.3 times for DMPHN, 6.7 times for IFI-RNN). Therefore, the proposed design achieves a balance between quality and speed compared with the existing methods. © 2022, The Authors. All rights reserved.

关键词： Pixels