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Study on the spectrum and far-field pattern of broad-area semiconductor lasers toward speckle suppression by optical feedback

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Optics Express 2025年第7期33卷 15742-15755页

作者： Chen, Ao Zhang, Weiqiao Zhou, Xuyan Liu, Jing Fu, Ting Zheng, Wanhua Laboratory of Solid State Optoelectronics Information Technology Institute of Semiconductors Chinese Academy of Sciences Beijing100083 China School of Electronic Electrical and Communication Engineering University of Chinese Academy of Sciences Beijing100049 China Weifang Academy of Advanced Opto-Electronic Circuits Weifang261000 China College of Future Technology University of Chinese Academy of Sciences Beijing100049 China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing100049 China State Key Laboratory on Integrated Optoelectronics Institute of Semiconductors Chinese Academy of Sciences Beijing100083 China

Laser diodes working at 940 nm are potential in video surveillance systems, but the speckle problem needs to be solved. Both the spectrum and far-field pattern of the broad-area semiconductor lasers (BALs) are important for speckle suppression of multimode fibers, but the relation between them has not been studied. In this paper, the time-averaged spectrum and far-field pattern of the BALs under optical feedback are studied in experiments and simulations. Effective spectral bandwidth and spot fill factor are introduced to evaluate the effective temporal coherence of the BALs and the relative numerical aperture of the coupled light. In-phase change between the effective spectral bandwidth and spot fill factor is observed under different feedback intensities, due to the spatial separation of the longitudinal modes. Low speckle contrast is obtained under 10% to ∼20% optical feedback, while stronger feedback may reduce the speckle suppression efficiency. A spectral bandwidth of 15.3 nm is observed under 10% feedback, but the spectral hole-burning is serious. The spectral hole-burning is partly suppressed by tuning the length of the external cavity. What we believe to be a novel low frequency fluctuation is observed in BALs at a high pump current, which may have some relation with the spatial bistability of the lateral modes. The spatiotemporal dynamic of BALs is simulated by a multimode model of BALs, and the spatial separation of the longitudinal modes is demonstrated. This work provides insight into the spectral and spatial characteristics of the BALs under optical feedback. © 2025 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.

关键词： Multimode fibers

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Transition metal-based cathode catalysts for Li-CO_(2)batteries

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Journal of Energy Chemistry 2025年第5期104卷 225-253页

作者： Wenqing Ma Mingjuan Gao Jianping Ma Siyu Liu Lishan Yang Yahui Yang Xiangping Chen Tianzhen Jian Institute for Advanced Interdisciplinary Research(iAIR) Collaborative Innovation Center of Technology and Equipment for Biological Diagnosis and Therapy in Universities of ShandongSchool of Chemistry and Chemical EngineeringUniversity of JinanJinan 250022ShandongChina Key Laboratory of Chemical Biology&Traditional Chinese Medicine Research(Ministry of Education of China) National and Local Joint Engineering Laboratory for New Petrochemical Materials and Fine Utilization of ResourcesKey Laboratory of the Assembly and Application of Organic Functional Molecules of Hunan ProvinceKey Laboratory of Light Energy Conversion Materials of Hunan Province CollegeHunan Normal UniversityChangsha 410081HunanChina Nano-Science Center&Department of Chemistry University of CopenhagenCopenhagen 2100Denmark Jinan Preschool Education College Jinan 250307ShandongChina State Key Laboratory of Crystal Materials Shandong UniversityJinan 250100ShandongChina Shandong Sacred Sun Power Sources Co.Ltd. Qufu 273100ShandongChina

The Li-CO_(2)battery has been highly rated as an intriguing technique for balancing the carbon cycle for years,but it is still significantly challenged by the obstacles such as limited reversibility,sluggish kinetics,and poor energy ***,the design and development of advance catalysts that can enhance the kinetics and reversibility of the CO_(2)electrochemical cycling reactions are considered the imperative *** metal-based catalysts are widely considered appealing owing to their unfilled dorbitals,rich and adjustable valences,as well as *** this review,the working mechanism and the key issues of the CO_(2)electrochemical cycling reaction are discussed *** the strategies for composition and structure design of different type of transition metal-based catalysts are highlighted,including their benefits,limitations,and the ways to implement these ***,based on the pioneering research,the perspectives on the challenges and key points for the future development of cathode catalyst are proposed.

关键词： Li-CO_(2)battery Transition metal Cathode catalyst Catalytic mechanism

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RGB-Based Category-Level Object Pose Estimation via Depth Recovery and Adaptive Refinement

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IEEE Robotics and Automation Letters 2025年第6期10卷 5377-5384页

作者： Yang, Hui Sun, Wei Liu, Jian Zheng, Jin Zeng, Zhiwen Mian, Ajmal Hunan University National Engineering Research Center for Robot Visual Perception and Control Technology College of Electrical and Information Engineering Changsha410082 China Hunan University State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Changsha410082 China Central South University School of Architecture and Art Changsha410082 China University of Western Australia Department of Computer Science and Software Engineering CrawleyWA6009 Australia

Category-level pose estimation methods have received widespread attention as they can be generalized to intra-class unseen objects. Although RGB-D-based category-level methods have made significant progress, reliance on depth image limits practical application. RGB-based methods offer a more practical and cost-effective solution. However, current RGB-based methods struggle with object geometry perception, leading to inaccurate pose estimation. We propose depth recovery and adaptive refinement for category-level object pose estimation from a single RGB image. We leverage DINOv2 to reconstruct the coarse scene-level depth from the input RGB image and propose an adaptive refinement network based on an encoder-decoder architecture to dynamically improve the predicted coarse depth and reduce its gap from the ground truth. We introduce a 2D–3D consistency loss to ensure correspondence between the point cloud obtained from depth projection and the objects in the 2D image. This consistency supervision enables the model to maintain alignment between the depth image and the point cloud. Finally, we extract features from the refined point cloud and feed them into two confidence-aware rotation regression branches and a translation and size prediction residual branch for end-to-end training. Decoupling the rotation matrix provides a more direct representation, which facilitates parameter optimization and gradient propagation. Extensive experiments on the REAL275 and CAMERA25 datasets demonstrate the superior performance of our method. Real-world estimation and robotic grasping experiments demonstrate our model robustness to occlusion, clutter environments, and low-textured objects. Our code and robotic grasping video are available at DA-Pose. © 2016 IEEE.

关键词： Depth perception

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Fabrication of Ultra-Low Absorption Thin Films via Ion Beam Assisted Electron Beam Evaporation

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High Power Laser Science and engineering 2025年

作者： Song, Ruichen Hu, Jiaqi Peng, Yunqi Xiao, Yingao Wang, Yuxiang Zhu, Kongxu Jiang, Yuheng Xia, Xusheng Xia, Zhilin Wuhan University of Technology State key laboratory of advanced glass materials Wuhan China Wuhan University of Technology Material Science and Engineering Wuhan China

High-power laser systems require thin films with extremely low absorption. Ultra-low absorption films are often fabricated via ion beam sputtering, which is costly and slow. This study analyzes the impact of doping titanium and annealing on the absorption characteristics of thin films, focusing on composition and structure. The results indicate that the primary factor influencing absorption is composition. By suppressing the presence of electrons or holes that do not form stable chemical bonds can significantly reduce absorption;For amorphous thin films, the structural influence on absorption is relatively minor. Thus, composition control is crucial for fabricating ultra-low absorption films, while the deposition method is secondary. Ion beam assisted electron beam evaporation, which is relatively seldom used for fabricating lowabsorption films, was employed to produce high-reflectivity films. After annealing, the absorption at 1064 nm reached 1.70 ppm. This method offers a cost-effective and rapid approach for fabricating ultra-low absorption films. © The Author(s), 2025. Published by Cambridge University Press in association with Chinese Laser Press.

关键词： Annealing

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Preparation of Blast Furnace Injection Fuel by Co-hydrothermal Carbonization of Polyvinyl Chloride and Pyrolytic Carbon Black

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Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science 2025年 1-14页

作者： Zhang, Nan Ning, Xiaojun Wang, Guangwei State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing100083 China School of Metallurgical and Ecological Engineering University of Science and Technology Beijing100083 China

Polyvinyl chloride (PVC) and waste tires are common waste pollutants and cannot be directly used as injection fuel in blast furnace (BF) due to harmful elements. PVC and waste tire pyrolysis carbon black (CB) were processed here by using an advanced hydrothermal carbonization (HTC) method to remove harmful elements, and the hydrochar for injection was also explored. Results showed that HTC had a significant dechlorination effect, and the chlorine content in PVC decreased by 44.16 pct. Meanwhile, the sulfur in CB also decreased by 0.13 pct. Compared with CB, the calorific value of PVC improved more after HTC, increasing by 75.86 pct. The dechlorination and dezincification effects of co-HTC are more efficient than those of hydrothermal alone. The particle size distribution of co-HTC hydrochar is more concentrated, with a more developed pore structure, the carbon order is close to that of anthracite and has good metallurgical properties. Kinetic results show that with the increase of the addition ratio of co-HTC hydrochar, the average reaction rate of the mixed fuel with the lowest activation energy is the highest at 40 pct. Thus, the hydrochar that meets the requirements of BF injection can be prepared by co-HTC of PVC and CB. © The Minerals, Metals & Materials Society and ASM International 2025.

关键词： Blast furnaces

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Experimental and numerical study on aerosol explosion characteristics and flame propagation behavior of hydrogen and gasoline spray mixtures

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International Journal of Hydrogen Energy 2025年 133卷 276-290页

作者： Yu, Ke Hu, Yong He, Lingfeng Wang, Xuegui Kai, Reo Watanabe, Hiroaki Kurose, Ryoichi State Key Laboratory of Fire Science University of Science and Technology of China Anhui Hefei230026 China School of New Energy Equipment Zhejiang College of Security Technology Wenzhou325016 China Department of Advanced Environmental Science and Engineering Kyushu University 6-1 Kasuga-koen Fukuoka Kasuga816-8580 Japan Department of Mechanical Engineering and Science Kyoto University Kyotodaigaku-katsura Nishikyo-ku Kyoto615-8540 Japan

Understanding the explosion characteristics and flame behaviors of hydrogen related aerosol mixtures is an important subject for the safety maintenance of various hydrogen production and supply chain. As such, in present work, an extensive explosion experiment was conducted in a 5 L duct for gasoline spray/H2 mixture with varying H2 and gasoline concentrations. The explosion pressure and transient flame morphology of gasoline spray/H2 aerosol were investigated, accompanied by a comprehensive analysis of chemical kinetics to elucidate the elementary reaction sensitivity and reaction paths that govern the combustion mechanism of mixed fuel. Results indicate that for median gasoline concentration, the peak explosion pressure of aerosol mixture first increases and then decreases when hydrogen component increases. Meanwhile, the peak explosion pressure shifts towards the lower hydrogen regime as gasoline concentration increases. The flame propagation of aerosol mixture with low gasoline concentration is close to that of gaseous fuel, which is characterized by a uniform combustion and is controlled by chemical dynamics. On the contrary, for higher gasoline concentration, the explosive mixture exhibits a heterogenous combustion, controlled by the multiphase devolatilization. Moreover, the reactions of O2+H[dbnd]O + OH and H2+OH[dbnd]H + H2O are the main pathways for hydrogen to participate in gasoline combustion and explosion, which improve the production rate of H, O, OH radicals and promote the reactivity of the hydrogen dual-fuel flame. © 2025 Hydrogen Energy Publications LLC

关键词： Crystallization kinetics

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Robust Watermarking Based on Multi-layer Watermark Feature Fusion

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IEEE Transactions on Multimedia 2025年

作者： Wu, Shaowu Lu, Wei Luo, Xiangyang Sun Yat-Sen University School of Computer Science and Engineering Ministry of Education Key Laboratory of Information Technology Guangdong Province Key Laboratory of Information Security Technology Guangzhou510006 China State Key Laboratory of Mathematical Engineering and Advanced Computing Henan450002 China

The purpose of robust image watermarking is to embed a watermark into a carrier image in an invisible form and extract the watermark successfully even under noise interference conditions to achieve copyright confirmation and traceability. Although watermarking methods based on deep learning can improve the robustness by adding a noise simulation layer, few theoretical analyses of the codec structure have been conducted. Theoretical explainability is the theoretical basis for developing a network architecture, which plays a guiding role in network development. On the basis of the interpretability of convolutional networks, this paper analyzes the mathematical process of embedding and extracting watermarks in codecs and proposes a novel watermarking framework based on multi-layer watermark feature fusion. Specifically, the encoder can be a convolutional network structure of arbitrary depth, whereas the decoder needs only to adopt its corresponding deconvolution structure. To improve the quality and robustness of the generated watermarked image, the watermark is associated with an arbitrary layer feature space in the decoder. In the decoder, the network quickly converges to each original encoding feature space through the deconvolution structure, thus decoupling the watermark features. Finally, the watermark is extracted via the automatic fusion of multi-layer watermark features. The experimental results show that the proposed method is suitable for few-shot learning, and its invisibility, robustness and generalization performance on multiple datasets are significantly better than those of other advanced methods. © 2025 IEEE.

关键词： Decoding

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Swarming Magnetic Fe_(3)O_(4)@Polydopamine-Tannic Acid Nanorobots:Integrating Antibiotic-Free Superficial Photothermal and Deep Chemical Strategies for Targeted Bacterial Elimination

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Research 2025年第1期2024卷 840-853页

作者： Luying Si Shuming Zhang Huiru Guo Wei Luo Yuqin Feng Xinkang Du Fangzhi Mou Huiru Ma Jianguo Guan State Key Laboratory of Advanced Technology for Materials Synthesis and Processing International School of Materials Science and EngineeringWuhan University of TechnologyWuhanChina Wuhan Institute of Photochemistry and Technology WuhanChina School of Chemistry Chemical Engineering and Life ScienceWuhan University of TechnologyWuhanChina

Micro/nanorobots(MNRs)are envisioned to provide revolutionary changes to therapies for infectious diseases as they can deliver various antibacterial agents or energies to many hard-to-reach infection ***,existing MNRs face substantial challenges in addressing complex infections that progress from superficial to deep ***,we develop swarming magnetic Fe3O4@polydopamine-tannic acid nanorobots(Fe3O4@PDA-TA NRs)capable of performing targeted bacteria elimination in complicated bacterial infections by integrating superficial photothermal and deep chemical *** Fe3O4@PDA-TA nanoparticles(NPs),serving as building blocks of the nanorobots,are fabricated by in situ polymerization of dopamine followed by TA *** driven by alternating magnetic fields,Fe3O4@PDA-TA NPs can assemble into large energetic microswarms continuously flowing forward with tunable ***,the swarming Fe3O4@PDA-TA NRs can be navigated to achieve rapid broad coverage of a targeted superficial area from a distance and rapidly eradicate bacteria residing there upon exposure to near-infrared(NIR)light due to their efficient photothermal ***,they can concentrate at deep infection sites by traversing through confined,narrow,and tortuous passages,exerting sustained antibacterial action through their surface TA-induced easy cell adhesion and subsequent membrane ***,the swarming Fe3O4@PDA-TA NRs show great potential for addressing complex superficial-to-deep *** study may inspire the development of future therapeutic microsystems for various diseases with multifunction synergies,task flexibility,and high efficiency.

关键词： therapies infectious diseases complex infections chemical therapy magnetic nanoparticles polydopamine photothermal therapy targeted bacteria elimination tannic acid

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Anomalous ductility-strength synergy occurred after cold rolling in a high Gd content Mg alloy

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材料科学技术（英文版） 2025年第4期207卷 177-190页

作者： Ning Lv Lingyu Zhao Hong Yan Boyu Liu Rongshi Chen Zhiwei Shan Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China School of Materials Science and Engineering Shenyang Ligong UniversityShenyang 110159China Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering Shandong University of Science and TechnologyQingdao 266590China Center for Advancing Materials Performance From the Nanoscale(CAMP-Nano)& Hysitron Applied Research Center in China(HARCC) State Key Laboratory for Mechanical Behavior of MaterialsXi'an Jiaotong UniversityXi'an 710049China Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

During cold rolling in magnesium(Mg)alloys,there will always be serious ductility deterioration,which greatly restricts the application of this processing *** this work,ductility-strength synergy oc-curred after cold rolling was carried out on a(0001)fiber textured Mg-17.5Gd-Zr alloy(wt.％).The ductility-strength synergy can be mainly attributed to texture randomization,microstructure refinement,and easier basal slip transfer condition in the twinned ***,the activation of multiple twinning behaviors,i.e.,{10-12},{10-11},and {11-21} twinning,and related twin-twin interaction restrict the formation of strong basal texture and facilitate the texture ***,profuse high-angle grain boundaries form through dislocation-twin interaction,twin-twin interaction,and dislocation inter-action,which promote microstructure ***,the basal slip transfer becomes easier in the twinned grains owing to the activation of multiple twinning behaviors and their ***-tion of {11-21} twinning anddislocations and the<0001>fiber texture which is favorable for multiple twinning activating during cold rolling are considered to be the key roles for microstructure and texture optimization.

关键词： Ductility-strength synergy {11-21} twin Cold rolling Texture Mg alloys

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Dual‑Donor‑Induced Crystallinity Modulation Enables 19.23% Efficiency Organic Solar Cells

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Nano-Micro Letters 2025年第3期17卷 376-388页

作者： Anhai Liang Yuqing Sun Sein Chung Jiyeong Shin Kangbo Sun Chaofeng Zhu Jingjing Zhao Zhenmin Zhao Yufei Zhong Guangye Zhang Kilwon Cho Zhipeng Kan Center On Nanoenergy Research Institute of Science and Technology for Carbon Peak&NeutralitySchool of Physical Science&TechnologyGuangxi UniversityNanning 530004People’s Republic of China Department of Chemical Engineering Pohang University of Science and TechnologyPohang 37673South Korea College of New Materials and New Energies Shenzhen Technology UniversityShenzhen 518118People’s Republic of China Zhejiang Engineering Research Center for Fabrication and Application of Advanced Photovoltaic Materials School of Materials Science and EngineeringNingboTech UniversityNingbo 315100People’s Republic of China State Key Laboratory of Featured Metal Materials and Life-Cycle Safety for Composite Structures Nanning 530004People’s Republic of China

Trap-assisted charge recombination is one of the primary limitationsof restricting the performance of organic solar cells. However, effectivelyreducing the presence of traps in the photoactive layer remains ***, wide bandgap polymer donor PTzBI-dF is demonstrated as an effectivemodulator for enhancing the crystallinity of the bulk heterojunction active layerscomposed of D18 derivatives blended with Y6, leading to dense and orderedmolecular packings, and thus, improves photoluminescence quenching *** a result, the photovoltaic devices exhibit reduced trap-assisted charge recombinationlosses, achieving an optimized power conversion efficiency of over 19%.Besides the efficiency enhancement, the devices comprised of PTzBI-dF as athird component simultaneously attain decreased current leakage, improved chargecarrier mobilities, and suppressed bimolecular charge recombination, leading toreduced energy losses. The advanced crystalline structures induced by PTzBI-dFand its characteristics, such as well-aligned energy level, and complementaryabsorption spectra, are ascribed to the promising performance *** findings suggest that donor phase engineering is a feasible approach to tuning the molecular packings in the active layer, providingguidelines for designing effective morphology modulators for high-performance organic solar cells.

关键词： Trap-assisted charge recombination Photoluminescence Miscibility Current leakage Power conversion efficiency

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