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Femtosecond laser-inscribed optical waveguides in dielectric crystals:a concise review and recent advances

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Advanced Photonics 2022年第2期4卷 23-51页

作者： Lingqi Li weijin kong Feng Chen Qingdao University College of Physics ScienceCenter for Marine Observation and CommunicationsQingdaoChina Shandong University School of PhysicsState Key Laboratory of Crystal MaterialsJinanChina

Femtosecond laser inscription or writing has been recognized as a powerful technique to engineer various materials toward a number of *** efficient modification of refractive indices of dielectric crystals,optical waveguides with diverse configurations have been produced by femtosecond laser *** waveguiding properties depend not only on the parameters of the laser writing but also on the nature of the *** mode profile tailoring and polarization engineering are realizable by selecting appropriate fabrication *** addition,regardless of the complexity of crystal refractive index changes induced by ultrafast pulses,several three-dimensional geometries have been designed and implemented that are useful for the fabrication of laser-written photonic *** intriguing devices,e.g.,waveguide lasers,wavelength converters,and quantum memories,have been made,exhibiting potential for applications in various *** work gives a concise review of the femtosecond laser-inscribed waveguides in dielectric crystals and focuses on the recent advances of this research area,including the fundamentals,fabrication,and selected photonic applications.

关键词： femtosecond laser writing femtosecond laser inscription optical waveguides dielectric crystals laser crystals nonlinear optical crystals waveguide lasers frequency/wavelength conversion quantum photonic chip quantum memories

Effect of OH^- on fluorescence properties in 1.5-1.6 μm for Er:Yb:YCOB crystal

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Journal of Rare Earths 2019年第9期37卷 924-930,I0001页

作者： Degao Zhong Chen Hu Shakir Ullah Hui Xu Jianhong Li Fei You Dongjuan Wang Shijia Sun weijin kong Jie Tang Zhenghe Yu Bing Teng College of Physics Qingdao UniversityQingdao 266071China National Demonstration Center for Experimental Applied Physics Education (Qingdao University) Qingdao 266071China CRYSTECH Inc. Qingdao 266107China Institute o f Engineering Materials Weifang Business Vocational CollegeWeifang 262234China

FTIR absorption spectra indicate that H^+can easily enter the crystal structure and form OH^-centers in Er:Yb:YCOB and O-H bonds prefer to lie in the a-c *** our current studied concentration level,crystal samples with higher OH-abso rption coefficie nts demonstrate stro nger fluo rescence intensity and longer fluorescence lifetime at 1535 *** the stretching vibration energy of OH-group approximately corresponds to the energy gap between the 4 I11/2 and 4 I13/2 levels of Er^3+,and thus,OH^-ions can shorten the fluorescence lifetime of Er^3+-4I11/2 level by the phonon-assisted cross-relaxation process between the Er^3+and *** curre nt results confirm that a certain conte nt of OH ions can enhance the ene rgy transfer process from Yb^3+to Er^3+and subsequently promote fluorescence output in 1.5-1.6μm.

关键词： Er:Yb:YCOB crystal OH^-ions Fluorescence output efficiency Energy transfer process Rare earths

Synthesis, crystal structure and thermal analysis of a new stilbazolium salt crystal

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Frontiers of Materials Science 2015年第2期9卷 147-150页

作者： Bing TENG weijin kong Ke FENG Fei YOU Lifeng CAO Degao ZHONG Lun HAO Qing SUN Sander van SMAALEN Wenhui GONG College of Physics Qingdao University Qingdao 266071 China Key Laboratory of Photonics Materials and Technology in Universi~iesof Shand'ongl Qingdao 266071 China Laboratory of Crystallography Universityof Bayreuth D-95440 BayreuihGermany

A new organic crystal of 4-N, N-dimethylamino-4＇-N＇-methyl-stilbazolium benzene sulfonate （DASBS） was synthesized and characterized for the first time. It is a derivative of 4-N, N-dimethylamino-4＇-N＇-methyl-stilbazolium tosylate （DAST） with the benzene sulfonate replacing p-toluenesulfonate. Single crystal XRD demonstrated that the crystal structure of DASBS. H20 was triclinic. The thermal analysis of this new crystal was also conducted, and the melting point was obtained to be 232℃.

关键词： organic crystal crystal growth single crystal X-ray diffraction thermalanalysis

In situ magnetometry study on the origin of anomalously capacity in transition metal sulfides

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ChemPhysMater 2023年第3期2卷 246-252页

作者： Yan Liu Yuanyuan Han Shuxuan Liao Fangchao Gu Hengjun Liu Xixiang Xu Zhiqiang Zhao Xiancheng Sang Qinghao Li weijin kong Qiang Li College of Physics University-Industry Joint Center for Ocean Observation and Broadband CommunicationWeihai Innovation Research InstituteQingdao UniversityQingdao 266071China

Cobalt sulfides are considered as promising candidates for lithium-ion battery(LIB)anode materials with high energy *** energy storage mechanism is widely understood to involve the traditional intercalation and conversion ***,these conventional mechanisms are unable to explain the storage capacities of certain materials which exceed the theoretical ***,utilizing advanced in situ magnetometry to detect the magnetization evolution of Co_(1-x) S LIBs in real time,it is demonstrated that the Co-catalytic lithium storage process and interfacial space charge storage mechanism are strongly related to the additional capacity of cobalt *** discharge,a Co/Li_(2) S interface is formed,wherein the Co nanoparticles and Li_(2) S could store a large amount of polarized electrons Li^(+),***,the electrons stored in Co are transferred to the polymeric film,forming radical anions and contributing extra *** findings reveal the charge storage mechanisms of transition metal sulfides and highlight the critical role of magnetic testing in the investigation of energy storage mechanisms.

关键词： Lithium-ion batteries Co_(1-x)S nanocomposites Additional capacity Energy storage mechanism

Domain Engineering the Flexoelectric Response of BaTiO_(3)–SrTiO_(3) Binary Films:A Phase Field Study

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Acta Mechanica Solida Sinica 2024年第4期37卷 590-597页

作者： Junyu Tao Fan Zhang Jianyuan Zhang weijin Chen Yue Zheng School of Materials Shenzhen Campus of Sun Yat-sen UniversityShenzhen518107China Guangdong Provincial Key Laboratory of Magnetoelectric Physics and Devices School of PhysicsSun Yat-sen UniversityGuangzhou510275China State Key Laboratory of Optoelectronic Materials and Technologies School of PhysicsSun Yat-sen UniversityGuangzhou510275China Centre for Physical Mechanics and Biophysics School of PhysicsSun Yat-sen UniversityGuangzhou510275China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai519082China

The flexoelectric effect describes the interplay between material polarization and strain *** much research has focused on control strategies for flexoelectricity,the impact of ferroelectric domain structure on the flexoelectric effect remains *** phase field simulations,we conduct a comparative study on the flexoelectric response of two types of BaTiO_(3)–SrTiO_(3) binary films:BaTiO_(3)–SrTiO_(3) multilayers and(Ba,Sr)TiO_(3) solid *** findings reveal that the flexoelectric response of these two systems,at the same Ba/Sr ratio,differs not only in magnitude but also in other aspects like temperature dependence,linearity,and hysteresis,due to their different ferroelectric domain structures and evolution *** study deepens our current understanding of flexoelectricity in ferroelectrics and suggests“domain engineering”as a potential way to tailor this effect.

关键词： Ferroelectric Flexoelectricity Multilayers Solid solution Phase field

Fluidization stability and periodic fluctuations in gas–solid separation fluidized bed using Geldart A dense medium

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Particuology 2024年第7期90卷 522-534页

作者： weijin Liu Dan Wang Liang Dong Enhui Zhou Tatiana Aleksandrova Chenyang Zhou Chenlong Duan Key Laboratory of Coal Processing and Efficient Utilization(China University of Mining&Technology) Ministry of EducationXuzhou 221116China School of Chemical Engineering&Technology China University of Mining&TechnologyXuzhou 221116China Department of Chemical and Biochemical Engineering The University of Western OntarioLondonOntario N6A 5B9Canada Mineral Processing Department Saint Petersburg Mining UniversitySt.Petersburg 199106Russia

Gas–solid separation fluidized bed is a typical method for coal separation without water *** A particles is also considered as the ideal dense medium to strengthen separation *** stability reflects the bed pressure fluctuations and the distribution of bubble and emulsion phases,affecting the separation *** the main frequency of pressure fluctuations can directly reflect the degree of pressure ***,the detailed fluidization stability is analyzed combined the method of standard deviation of pressure fluctuations,power spectral density,etc.,for Geldart A *** results showed that maintaining an appropriate gas velocity resulted in an average bed pressure of around 2000 *** main frequency is mainly concentrated around 1–1.5 ***,a prediction model of the main frequency of pressure fluctuations is established,and the error can be controlled within±*** investigation further proved the stable fluidization of Geldart A particles and provides a method for predicting the main frequency of pressure fluctuations in the gas–solid separation fluidized bed.

关键词： Geldart A dense medium Fluidization stability Periodic fluctuations Pressure fluctuations frequency Gas–solid separation fluidized bed

Pd-Catalyzed Dienylation of Propargylic Esters Enabling Highly Stereoselective Synthesis of Danishefsky-Type Trisubstituted Dienes

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Chinese Journal of Chemistry 2024年第17期42卷 1993-1998页

作者： Chen Zhou Mengfu Dai Xiaoyu Yin Mingyue Zhang weijin Gu Liang-An Chen Jiangsu Collaborative Innovation Center of Biomedical Functional Materials Jiangsu Key Laboratory of New Power BatteriesSchool of Chemistry and Materials ScienceNanjing Normal UniversityNanjingJiangsu 210023China

The stereochemical synthesis of highly substituted Danishefsky-type dienes remains unsolved in organic *** describe a simple and efficient approach for the stereoselective synthesis of Danishefsky-type trisubstituted dienes from readily available propargylic esters via Pd-catalyzed dienylation reaction through the key intermediate metallacyclobutene in a regio-,chemo-and stereoselective *** method facilitates a broad range of challenging trisubstituted dienes with a high level of stereocontrol.

关键词： Propargylic ester Dienylation Diene Stereoselectivity Cycloaddition Palladium β-H elimination Regioselectivity

Tuning anionic/cationic redox chemistry in a P2-type Na0.67Mn0.5Fe0.5O2 cathode material via a synergic strategy

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Science China Materials 2020年第9期63卷 1703-1718页

作者： weijin kong Wenyun Yang De Ning Qingyuan Li Lirong Zheng Jinbo Yang Kai Sun Dongfeng Chen Xiangfeng Liu Center of Materials Science and Optoelectronics Engineering College of Materials Science and Optoelectronic TechnologyUniversity of Chinese Academy of SciencesBeijing 100049China State Key Laboratory for Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100871China Helmholtz-Center Berlin for Materials and Energy Hahn-Meitner-Platz 1Berlin 14109Germany Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China Department of Nuclear Physics China Institute of Atomic EnergyBeijing 102413China CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of SciencesBeijing 100190China

The anionic redox chemistry(O^2-→O^-)in P2-type sodium-ion battery cathodes has attracted much ***,determining how to tune the anionic redox reaction is still a major ***,we tune the activity and reversibility of both the anionic and cationic redox reactions of Na0.67Mn0.5Fe0.5O2 though an integrated strategy that combines the advantages of Li2SiO3 coating,Li doping and Si doping,and the initial capacity,rate performance and cycling stability are significantly *** in-depth modulation mechanism is revealed by means of neutron diffraction,X-ray absorption spectroscopy,in situ X-ray diffraction,electron paramagnetic resonance spectroscopy,first-principles calculations and so *** Li2SiO3 coating alleviates the side reactions and enhances the cycling ***^4+doping lowers the Na^+diffusion barrier due to the expanded interlayer ***,Si^4+doping improves the structural stability,oxygen redox activity and ***^+doping in Na sites further increases the structure *** electron density maps confirm the greater activity of Na and O in the modified *** density maps and bond-valence energy landscapes identify the Na^+migration pathway from Nae site to Naf site(the positions of the Na ions in the crystal structure).The proposed insights into the modulation mechanism of the anionic and cationic redox chemistry are also instructive for designing other oxide-based cathode materials.

关键词： sodium-ion battery P2-type cathode anion redox electron density nephogram Li2SiO3 coating

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二维光子晶体分束器和偏转器

光学学报 2009年第3期29卷 818-821页

作者：孔伟金云茂金王美单福凯青岛大学物理科学学院山东青岛266071

针对二维光子晶体在光束调整和光束偏转中的应用,采用平面波展开法、二维有限时域差分法和完全匹配层吸收边界条件,从理论上研究了二维方形光子晶体结构中TM模式的自准直现象。通过分析光子晶体的能带结构和等频图,基于二维光子晶体的... 详细信息

针对二维光子晶体在光束调整和光束偏转中的应用,采用平面波展开法、二维有限时域差分法和完全匹配层吸收边界条件,从理论上研究了二维方形光子晶体结构中TM模式的自准直现象。通过分析光子晶体的能带结构和等频图,基于二维光子晶体的自准直效应和光子带隙,对光波在二维光子晶体中的传播特性进行了讨论。数值计算表明,通过在合适的方向引入不同的线缺陷,可以实现自准直光束的1×2和1×3分束以及光束偏转。最后讨论了透射光束和偏转光束的能量随线缺陷半径的变化关系。所设计的器件极大地扩展了光子晶体在高密度光学集成电路中的应用。

关键词：光学材料光子晶体自准直效应有限时域差分方法线缺陷