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Microwave Photonic systems for Demodulation of Optical Fiber Interference Signals

Photonic Sensors 2025年第1期15卷 61-80页

作者： Yuru CHEN Xiaohua LEI Xianming LIU Peng ZHANG Key Lab of Optoelectronic Technology&Systems(Chongqing University) Ministry of EducationCollege of Optoelectronic EngineeringChongqing UniversityChongqing400044China

Fiber optic sensors have been gradually used in aerospace,petrochemical,electronic power,civil engineering,and biomedical fields because of their many advantages such as the anti-electromagnetic interference,corrosion resistance,light weight,small size,high accuracy,and easy *** recent years,sensing and demodulation technologies based on microwave photonics have attracted widespread *** fiber sensing combined with microwave photonics has higher sensitivity and flexibility,which is important for the demodulation of interferometric *** article introduces and analyzes the principle,structure,and performance of the demodulation technology of fiber optic interferometric signals based on microwave photonics from the perspective of system structures,such as filters,oscillators,and interferometers,and discusses the future research and development directions.

关键词： Microwave photonics optic fiber sensing interference structure

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Score-based Generative Model with Conditional Null-space Learning for Limited-angle Tomographic Reconstruction in Medical Imaging

IEEE Transactions on Computational Imaging

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IEEE Transactions on Computational Imaging 2025年 11卷 556-569页

作者： Zhang, Genyuan Wang, Zihao Yu, Haijun Ni, Song Xie, Haixia Liu, Qiegen Liu, Fenglin Wang, Shaoyu Chongqing University Key Lab of Optoelectronic Technology and Systems Engineering Research Center of Industrial Computed Tomography Nondestructive Testing Ministry of Education Chongqing400044 China School of Information Engineering Jiangxi Nanchang330031 China

Limited-angle computed tomography (LA-CT) reconstruction represents a typically ill-posed inverse problem, frequently resulting in reconstructions with noticeable edge divergence and missing features. Score-based generative models (SGMs) based reconstruction methods have shown strong ability to reconstruct high-fidelity images for LA-CT. Data consistency is crucial for generating reliable and high-quality results in SGMs-based reconstruction methods. However, existing deep reconstruction methods have not fully explored data consistency, resulting in suboptimal performance. Based on this, we proposed a Conditional Score-based Null-space (CSN) generative model for LA-CT reconstruction. First, CSN integrates prior physical information of limited-angle scanning as conditional constraint, which can enable SGMs to obtain more accurate generation. Second, in order to balance the consistency and realness of the reconstruction results, the range-null space decomposition strategy is introduced in the sampling process. This strategy ensures that the estimation of the information occurs only in the null-space. Finally, we employ the sparse least square (LSQR) instead of commonly used consistency terms such as simultaneous iterative reconstruction technique (SIRT), thereby achieving superior reconstruction results. In addition, a mathematical convergence analysis of our CSN method is provided. Experimental evaluations on both numerical simulations and real-world datasets demonstrate that the proposed method offers notable advantages in reconstruction quality. © 2015 IEEE.

关键词： Iterative methods

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Planar Hall plateau in magnetic Weyl semimetals

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Science Bulletin 2025年第2期70卷 187-192页

作者： Lei Li Chaoxi Cui Run-Wu Zhang Zhi-Ming Yu Yugui Yao Centre for Quantum Physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement(MOE)School of PhysicsBeijing Institute of TechnologyBeijing 100081China Beijing Key Lab of Nanophotonics&Ultrafine Optoelectronic Systems School of PhysicsBeijing Institute of TechnologyBeijing 100081China International Center for Quantum Materials Beijing Institute of TechnologyZhuhai 519000China

Despite the rapid progress in the study of planar Hall effect(PHE)in recent years,all the previous works only showed that the PHE is connected to local geometric quantities,such as Berry ***,for the first time,we point out that the PHE in magnetic Weyl semimetals is directly related to a global quantity,namely,the Chern number of the Weyl *** leads to a remarkable consequence that the PHE observation predicted here is robust against many system details,including the Fermi *** main difference between non-magnetic and magnetic Weyl points is that the latter breaks time-reversal symmetry T,thus generally possessing an energy *** semiclassical Boltzmann theory,we investigate the PHE in generic magnetic Weyl models with energy tilt and arbitrary Chern *** find that by aligning the magnetic and electric fields in the same direction,the trace of the PHE conductivity contributed by Berry curvature and orbital moment is proportional to the Chern number and the energy tilt of the Weyl points,resulting in a previously undiscovered quantized PHE plateau by varying the Fermi *** further confirm the existence of PHE plateaus in a more realistic lattice model without T *** proposing a new quantized physical quantity,our work not only provides a new tool for extracting the topological character of the Weyl points but also suggests that the interplay between topology and magnetism can give rise to intriguing physics.

关键词： Magnetic Weyl semimetals Planar Hall effect Quantized plateau Chern number

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Layer Nernst and thermal Hall effects in two-dimensional antiferromagnets

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Physical Review B 2025年第10期111卷 104405-104405页

作者： Xiangju Wang Ling Bai Yugui Yao Centre for Quantum Physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE) School of Physics Beijing Institute of Technology Beijing 100081 China and Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems School of Physics Beijing Institute of Technology Beijing 100081 China

In two-dimensional (2D) layered materials, the layer acts as a crucial degree of freedom, enabling the emergence of exotic physical phenomena through its coupling with charge and spin. Here, using first-principles calculations and group theory analysis, we reveal that layer Nernst and layer thermal Hall effects are present in various 2D A-type layered antiferromagnets, including the metal Hf2S, the normal insulator CrI3, and the topological insulator MnBi2Te4. The application of an out-of-plane electric field removes the key magnetic group symmetries and breaks the spin degeneracy of the electronic structures in these 2D antiferromagnets. This spin splitting induces an imbalanced distribution of Berry curvature between the top and bottom layers. By quantitatively calculating the layer-resolved Nernst and thermal Hall conductivities, we confirm the existence of nonzero transverse charge and heat currents in response to a longitudinal temperature gradient field. The calculated conductivities are comparable to, or might even exceed, those of previously well-known altermagnets and noncollinear antiferromagnets that exhibit anomalous Nernst and thermal Hall effects. Our findings provide deeper insights into the thermal transport properties of 2D layered antiferromagnets and pave the way for future developments in antiferromagnetic spintronics, spin caloritronics, and layertronics.

关键词： Topological insulators

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General electronic structure calculation method for twisted systems

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Physical Review B 2025年第7期111卷 075434-075434页

作者： Junxi Yu Shifeng Qian Cheng-Cheng Liu Centre for Quantum Physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE) and Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems School of Physics Beijing Institute of Technology Beijing 100081 China Anhui Province Key Laboratory for Control and Applications of Optoelectronic Information Materials Department of Physics Anhui Normal University Anhui Wuhu 241000 China

In recent years, two-dimensional twisted systems have gained increasing attention. However, calculating the electronic structures in twisted materials has remained a challenge. To address this, we have developed a general computational methodology that can generate twisted geometries starting from a monolayer structure and obtain a precisely relaxed twisted structure through a machine learning-based method. Then, the electronic structure properties of the twisted material are calculated using the tight-binding (TB) and continuum model methods; thus, the entire process requires minimal computational resources. We introduce the theoretical methods for generating twisted structures and computing their electronic properties, and further provide calculations and brief analyses of the electronic structure properties for several typical two-dimensional materials with different characteristics. This paper serves as a solid foundation for researchers interested in studying twisted systems.

关键词： Electronic properties

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Design of Intrinsic Transparent Conductors from a Synergetic Effect of Symmetry and Spatial-Distribution Forbidden Transitions

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Physical Review Letters 2025年第3期134卷 036401-036401页

作者： Gui Wang Ying Ning Du Pu Huang Zheng Fang Qian Peng Zhang Su-Huai Wei Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen 518060 China 21C Innovation Laboratory Contemporary Amperex Technology Ltd. (21C LAB) Fujian Ningde 352100 China Eastern Institute of Technology Ningbo 315200 China

Intrinsic transparent conductors (ITCs) correspond to a unique class of TCs that do not need intentional doping. This character can provide ITCs significant advantages by avoiding severe “doping bottlenecks” and dopant scattering usually encountered in conventional transparent conducting oxides (TCOs). However, the realization of ITCs generally requires the minimization of photon absorption and reflection in metallic conductors, which is difficult due to the gapless nature of their band structures. Here, based on first-principles calculations, we illustrate a feasible strategy to design optical transparency in metallic conductors by a synergetic effect of symmetry and spatial-distribution forbidden transitions between their energy bands around the Fermi level. The validity of this design strategy is demonstrated in a zero-dimensional electride, K4Al3(SiO4)3, which exhibits both electrical conductivity and optical transparency in the ultraviolet spectrum. More interestingly, we find that this transmittance range can be tuned to the visible spectrum region by chemical substitutions in K4Al3(SiO4)3 with the elements that have either larger electronegativity or smaller atomic radius. By examining dozens of possible cation substitutions via high-throughput calculations, we identify several promising candidates that have the potential as ITCs.

关键词： Transparent conducting oxides

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Monoclinic nonlinear metasurfaces for resonant engineering of polarization states

arXiv

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arXiv 2025年

作者： Toftul, Ivan Hariharan, Dhruv Tonkaev, Pavel Lai, Fangxing Song, Qinghai Kivshar, Yuri Research School of Physics Australian National University CanberraACT2601 Australia Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information System Guangdong Provincial Key Laboratory of Semiconductor Optoelectronic Materials and Intelligent Photonic Systems Harbin Institute of Technology Shenzhen518055 China

Polarization is a fundamental property of light that can be engineered and controlled efficiently with optical metasurfaces. Here, we employ chiral metasurfaces with monoclinic lattice geometry and achiral meta-atoms for resonant engineering of polarization states of light. We demonstrate, both theoretically and experimentally, that a monoclinic metasurface can convert linearly polarized light into elliptically polarized light not only in the linear regime but also in the nonlinear regime with the resonant generation of the third-harmonic field. We reveal that the ellipticity of the fundamental and higher-harmonic fields depends critically on the angle of the input linear polarization, and the effective chiral response of a monoclinic lattice plays a significant role in the polarization conversion. © 2025, CC BY.

关键词： Harmonic generation

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Quantized Spin-Hall Conductivity in Altermagnet Fe2Te2O with Mirror-Spin Coupling

arXiv

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arXiv 2025年

作者： Zhang, Run-Wu Cui, Chaoxi Wang, Yang Duan, Jingyi Yu, Zhi-Ming Yao, Yugui Beijing Key Lab of Nanophotonics & Ultrafine Optoelectronic Systems School of Physics Beijing Institute of Technology Beijing100081 China International Center for Quantum Materials Beijing Institute of Technology Zhuhai519000 China

Due to spin-orbit coupling (SOC), crucial for the quantum spin Hall (QSH) effect, a quantized spin-Hall conductivity has not yet been reported in QSH insulators and other realistic materials. Here, we tackle this challenge by predicting robust quantized spin-Hall conductivity in monolayer Fe2Te2O. The underlying physics originates from the unrecognized mirror-spin coupling (MSC), which couples spin-up and spin-down states into two orthogonal mirror eigenstates. We show that the MSC can naturally emerge in the two-dimensional altermagnets with out-of-plane Néel vector and horizontal mirror. A remarkable consequence of the MSC is that it can dramatically weaken the spin hybridization of the altermagnetic materials when SOC is included. When SOC is neglected, Fe2Te2O is an altermagnetic Weyl semimetal with MSC. With SOC, it evolves into the first material candidate for magnetic mirror Chern insulator. Remarkably, under the protection of MSC, the spin hybridization of both bulk and topological edge states in Fe2Te2O with SOC at low energy is negligible. As a consequence, a quantized spin-Hall conductivity emerges within the bulk band gap of the system. By unveiling a novel effect, our findings represent a significant advancement in spin Hall transport, and broaden the material candidates hosting intriguing altermagnetic phenomena. © 2025, CC BY.

关键词： Spin orbit coupling

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MCRANet: MTSL-based connectivity region attention network for PD-L1 status segmentation in H&E stained images

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Computers in Biology and Medicine 2025年 184卷 109357-109357页

作者： Deng, Xixiang Luo, Jiayang Huang, Pan He, Peng Li, Jiahao Liu, Yanan Xiao, Hualiang Feng, Peng The Key Lab of Optoelectronic Technology and Systems Ministry of Education Chongqing University Chongqing400044 China Department of Pathology Daping Hospital Army Medical University Chongqing400037 China Department of Electronic Information Engineering Chongqing Technology and Business and Institute Chongqing401520 China

The quantitative analysis of Programmed death-ligand 1 (PD-L1) via Immunohistochemical (IHC) plays a crucial role in guiding immunotherapy. However, IHC faces challenges, including high costs, time consumption and result variability. Conversely, Hematoxylin-Eosin (H&E) staining offers cost-effectiveness, speed, and stable results. Nonetheless, H&E staining, which solely visualizes cellular morphological features, lacks clinical applicability in detecting biomarker expressions like PD-L1. Substituting H&E staining for IHC in determining PD-L1 status is a clinically significant and challenging task. Motivated by above observations, we propose a Multi-Task supervised learning (MTSL)-based connectivity region attention network (MCRANet) for PD-L1 status segmentation in H&E stained images. To reduce interference from non-tumor areas, the MTSL-based region attention is proposed to enhances the network's capability to distinguish between tumor and non-tumor regions. Consequently, this augmentation further improves the network's segmentation efficacy for PD-L1 positive and negative regions. Furthermore, the PD-L1 expression regions demonstrate interconnection throughout the tissue section. Leveraging this topological prior knowledge, we integrate a connectivity modeling module (CM module) within the MTSL-based region attention module (MRA module) to enhance the precision of MTSL-based region attention localization. This integration further improves the structural similarity between the segmentation results and the ground truth. Extensive visual and quantitative results demonstrate that our supervised-learning-guided MRA module produces more interpretable attention and the introduced CM module provides accurate positional attention to the MRA module. Compared to other state-of-the-art networks, MCRANet exhibits superior segmentation performance with a dice similarity coefficient (DSC) of 79.6 % on the lung squamous cell carcinoma (LUSC) PD-L1 status dataset. © 2024 Elsevier

关键词： Image segmentation

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Ultrafast coherent phonon dynamics in the kagome magnet GdV6Sn6

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Physical Review B 2025年第5期111卷 054308-054308页

作者： Juntao Fu Yadong Han Yuting Wang Huangyu Wu Yunfang Yang Rongxiao Du Jianzhou Zhao Hang Zhang Junhong Yu State Key Laboratory for Environment-Friendly Energy Materials Southwest University of Science and Technology Mianyang 621010 China Laboratory for Shock Wave and Detonation Physics Institute of Fluid Physics China Academy of Engineering Physics Mianyang 621900 China Co-Innovation Center for New Energetic Materials Southwest University of Science and Technology Mianyang 621010 China School of Science Southwest University of Science and Technology Mianyang 621010 China Centre for Quantum Physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE) School of Physics Beijing Institute of Technology Beijing 100081 China Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems Beijing Institute of Technology Beijing 100081 China

The kagome intermetallic compound RV6Sn6 (R=rare earth) not only supports unique lattice geometries and nontrivial topological band structures but also exhibits long-range magnetic order at low temperatures, providing an ideal platform for studying interactions among electrons, phonons, and magnetism. Phonons play a crucial role in the coupling between magnetic order and topological fermions, whose dynamics are essential for understanding the complex multiple degrees of freedom interaction in RV6Sn6. In this work we systematically investigate the temperature-dependent coherent phonon dynamics of GdV6Sn6, and two characteristic temperature points have been identified (i.e., Te at ∼100K and Tm at ∼5K). Specifically, we have observed the anomalous softening and suppressed decaying of the Ag4 phonon mode when approaching Te, which may result from the change of density of states near the Fermi surface, while around Tm, the hardening and accelerated decaying of the Ag4 phonon mode emerges since the buildup of magnetic order alters the phonon energy renormalization and opens an additional scattering channel.

关键词： Fermions

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