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High spatial and temporal resolution synthetic aperture phase microscopy

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Advanced Photonics 2020年第6期2卷 78-85页

作者： Cheng Zheng Di Jin Yanping He Hongtao Lin Juejun Hu Zahid Yaqoo Peter T.C.So Renjie Zhou The Chinese University of Hong Kong Department of Biomedical EngineeringHong KongChina Massachusetts Institute of Technology Department of Mechanical EngineeringCambridgeMassachusettsUnited States Massachusetts Institute of Technology Computer Science and Artificial Intelligence LaboratoryCambridgeMassachusettsUnited States Zhejiang University College of Information Science and Electronic EngineeringHangzhouChina Massachusetts Institute of Technology Department of Materials Science and EngineeringCambridgeMassachusettsUnited States Massachusetts Institute of Technology Laser Biomedical Research CenterCambridgeMassachusettsUnited States Massachusetts Institute of Technology Department of Biological EngineeringCambridgeMassachusettsUnited States The Chinese University of Hong Kong Shun Hing Institute of Advanced EngineeringHong KongChina

A new optical microscopy technique,termed high spatial and temporal resolution synthetic aperture phase microscopy(HISTR-SAPM),is proposed to improve the lateral resolution of wide-field coherent *** plane wave illumination,the resolution is increased by twofold to around 260 nm,while achieving millisecond-level temporal *** HISTR-SAPM,digital micromirror devices are used to actively change the sample illumination beam angle at high speed with high *** off-axis interferometer is used to measure the sample scattered complex fields,which are then processed to reconstruct high-resolution phase *** HISTR-SAPM,we are able to map the height profiles of subwavelength photonic structures and resolve the period structures that have 198 nm linewidth and 132 nm gap(i.e.,a full pitch of 330 nm).As the reconstruction averages out laser speckle noise while maintaining high temporal resolution,HISTR-SAPM further enables imaging and quantification of nanoscale dynamics of live cells,such as red blood cell membrane fluctuations and subcellular structure dynamics within nucleated *** envision that HISTR-SAPM will broadly benefit research in material science and biology.

关键词： quantitative phase microscopy label-free imaging material inspection cell dynamics observation

spatial-temporal heterogeneity and determinants of HIV prevalence in the Mano River Union countries

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Infectious Diseases of Poverty 2022年第6期11卷 96-96页

作者： Idrissa Laybohr Kamara Liang Wang Yaxin Guo Shuting Huo Yuanyuan Guo Chengdong Xu Yilan Liao William J.Liu Wei Ma George F.Gao Department of Epidemiology School of Public HealthCheeloo College of MedicineShandong UniversityJinan 250012China NHC Key Laboratory of Biosafety National Institute for Viral Disease Control and PreventionChinese Center for Disease Control and PreventionBeijing 102206China 不详

Background:Utilizing population-based survey data in epidemiological research with a spatial perspective can integrate valuable context into the dynamics of HIV prevalence in West ***,the situation in the Mano River Union(MRU)countries is largely *** research aims to perform an ecological study to determine the HIV prevalence patterns in ***:We analyzed Demographic and Health Survey(DHS)and AIDS Indicator Survey(AIS)data on HIV prevalence in MRU from 2005 to *** examined the country-specifc,regional-specifc and sex-specifc ratios of respondents to profle the spatial–temporal heterogeneity of HIV prevalence and determine HIV hot *** employed Geodetector to measure the spatial stratifed heterogeneity(SSH)of HIV prevalence for adult women and *** assessed the comprehensive correct knowledge(CCK)about HIV/AIDS and HIV testing uptake by employing the Least Absolute Shrinkage and Selection Operator(LASSO)regression to predict which combinations of CCKs can scale up the ratio of HIV testing uptake with sex-specifc ***:In our analysis,we leveraged data for 158,408 respondents from 11 surveys in the *** 2005–2015,Cote d’Ivoire was the hot spot for HIV prevalence with a Gi_Bin score of 3,Z-Score 8.0–10.1 and Pspatial distribution of HIV prevalence in the MRU is skewed and the CCK about HIV/AIDS and HIV testing uptake are far below the threshold target set by UNAIDS for ending the epidemic in the *** detected statistically signifcant SSH w

关键词： spatial distribution of HIV prevalence Geodetector spatial stratifed heterogeneity Least Absolute Shrinkage and Selection Operator Comprehensive correct knowledge Machine learning Africa

Combining single-cell RNA sequencing with spatial transcriptome analysis reveals dynamic molecular maps of cambium differentiation in the primary and secondary growth of trees

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Plant Communications 2023年第5期4卷 46-62页

作者： Renhui Li Zhifeng Wang Jia-Wei Wang Laigeng Li National Key Laboratory of Plant Molecular Genetics and CAS center for Excellence in Molecular Plant Sciences Institute of Plant Physiology and EcologyChinese Academy of SciencesShanghai 200032China University of the Chinese Academy of Sciences Beijing 100049China School of Life Science and Technology ShanghaiTech UniversityShanghai 201210China

Primary and secondary growth of the tree stem are responsible for corresponding increases in trunk height and ***,our molecular understanding of the biological processes that underlie these two types of growth is *** this study,we used single-cell RNA sequencing and spatial transcriptome sequencing to reveal the transcriptional landscapes of primary and secondary growth tissues in the Populus *** between the cell atlas and differentiation trajectory of primary and secondary growth revealed different regulatory networks involved in cell differentiation from cambium to xylem precursors and phloem *** regulatory networks may be controlled by auxin accumulation and *** of cell differentiation trajectories suggested that vessel and fiber development followed a sequential pattern of progressive transcriptional *** research provides new insights into the processes of cell identity and differentiation that occur throughout primary and secondary growth of tree stems,increasing our understanding of the cellular differentiation dynamics that occur during stemgrowth in trees.

关键词： scRNA-seq spatial transcriptome primary growth secondary growth secondary cell wall SCW Populus

Halftone spatial frequency domain imaging enables kilohertz high-speed label-free non-contact quantitative mapping of optical properties for strongly turbid media

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Light(Science & Applications) 2021年第12期10卷 2518-2530页

作者： Yanyu Zhao Bowen Song Ming Wang Yang Zhao Yubo Fan Beijing Advanced Innovation center for Biomedical Engineering Key Laboratory for Biomechanics and Mechanobiology of Ministry of EducationSchool of Engineering Medicineand with the School of Biological Science and Medical EngineeringBeihang University100191 BeijingChina Institute of Spacecraft Application System Engineering China Academy of Space Technology100094 BeijingChina Beijing Institute of Spacecraft Engineering 100094 BeijingChina

The ability to quantify optical properties(i.e.,absorption and scattering)of strongly turbid media has major implications on the characterization of biological tissues,fluid fields,and many ***,there are few methods that can provide wide-field quantification of optical properties,and none is able to perform quantitative optical property imaging with high-speed(e.g.,kilohertz)*** we develop a new imaging modality termed halftone spatial frequency domain imaging(halftone-SFDI),which is approximately two orders of magnitude faster than the state-of-the-art,and provides kilohertz high-speed,label-free,non-contact,wide-field quantification for the optical properties of strongly turbid *** method utilizes halftone binary patterned illumination to target the spatial frequency response of turbid media,which is then mapped to optical properties using model-based *** validate the halftone-SFDI on an array of phantoms with a wide range of optical properties as well as in vivo human *** demonstrate with an in vivo rat brain cortex imaging study,and show that halftone-SFDI can longitudinally monitor the absolute concentration as well as spatial distribution of functional chromophores in *** also show that halftone-SFDI can spatially map dual-wavelength optical properties of a highly dynamic flow field at kilohertz ***,these results highlight the potential of halftone-SFDI to enable new capabilities in fundamental research and translational studies including brain science and fluid dynamics.

关键词： optical scattering media

Active spatial control of photothermal heating and thermo-actuated convective flow by engineering a plasmonic metasurface with heterodimer lattices

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Photonics research 2022年第11期10卷 2642-2657页

作者： ZHIMIN JING PEIHANG LI CUIPING MA JIAYING WANG ROBERTO CAPUTO ALEXANDER OGOVOROV ARUP NEOGI HONGXING XU ZHIMING WANG Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 610054China Physics Department University of CalabriaRende I-87036Italy Department of Physics and Astronomy and Nanoscale and Quantum Phenomena Institute Ohio UniversityAthensOhio 45701USA School of Physics and Technology Center for Nanoscience and NanotechnologyWuhan UniversityWuhan 430072China Institute for Advanced Study Chengdu UniversityChengdu 610106China

Thermo-plasmonics, using plasmonic structures as heat sources, has been widely used in biomedical and microfluidic applications. However, a metasurface with single-element unit cells, considered as the sole heat source in a unit cell, functions at a fixed wavelength and has limited control over the thermo-plasmonically induced hydrodynamic effects. Plasmonic metasurfaces with metal disk heterodimer lattices can be viewed to possess two heat sources within a unit cell and are therefore designed to photo-actively control thermal distributions and fluid dynamics at the nanoscale. The locations of heat sources can be switched, and the direction of the convective flow in the central region of the unit cell can be reversed by shifting the wavelength of the excitation source without any change in the excitation direction or physical actuation of the structural elements. The temperature and velocity of a fluid are spatiotemporally controlled by the wavelength selectivity and polarization sensitivity of the plasmonic metasurface. Additionally, we investigate the effects of geometric parameters on the surface lattice resonances and their impact on the temperature and fluid velocity of the optofluidic system. Our results demonstrate excellent optical control of these plasmonic metasurface heating and thermal convection performances to design flexible platforms for microfluidics.

关键词： excitation reversed flow

Defects inducing anomalous exciton kinetics in monolayer WS_(2)

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Nano research 2022年第2期15卷 1616-1622页

作者： Zhe Li Yan Zeng Zhenwei Ou Tianzhu Zhang Rongguang Du Ke Wu Quanbing Guo Wei Jiang Yuhao Xu Tao Li Tai Min Ti Wang Hongxing Xu School of Physics and Technology Center for Nanoscience and Nanotechnologyand Key Laboratory of Artificial Micro-and Nanostructures of Ministry of EducationWuhan UniversityWuhan 430072China Institute of Microscale Optoelectronics Shenzhen UniversityShenzhen 518060China center for Spintronics and Quantum System State Key Laboratory for Mechanical Behavior of MaterialsSchool of Materials Science and EngineeringXian Jiaotong UniversityXian 710049China

Two-dimensional(2D)transition metal dichalcogenide(TMD)has emerged as an effective optoelectronics material due to its novel optical *** the role of defects in exciton kinetics is crucial for achieving high-efficiency TMD ***,we observe defects induced anomalous power dependence exciton dynamics and spatial distribution in hexagonal heterogeneous WS_(2).With transient absorption microscopy study,we illustrate that these phenomena originate from the competition between radiative and defect-related non-radiative *** understand the physics behind this,a decay model is introduced with two defect-related channels,which demonstrates that more excitons decay through non-radiative channels in the dark region than the bright *** work reveals the mechanisms of anomalous exciton kinetics by defects and is instrumental for understanding and exploiting excitonic states in emerging 2D semiconductors.

关键词： transition metal dichalcogenides defect exciton dynamics transient absorption microscopy

Spatiotemporal rotational dynamics of laser-driven molecules

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Advanced Photonics 2020年第2期2卷 18-38页

作者： Kang Lin Ilia Tutunnikov Junyang Ma Junjie Qiang Lianrong Zhou Olivier Faucher Yehiam Prior Ilya Sh.Averbukh Jian Wu East China Normal University State Key Laboratory of Precision SpectroscopyShanghaiChina bWeizmann Institute of Science Department of Chemical and Biological PhysicsRehovotIsrael Universite de Bourgogne Franche-Comte Laboratoire Interdisciplinaire CARNOT de BourgogneUMR 6303 CNRSDijonFrance Shanxi University Collaborative Innovation Center of Extreme OpticsTaiyuanShanxiChina

Molecular alignment and orientation by laser fields has attracted significant attention in recent years,mostly due to new capabilities to manipulate the molecular spatial *** can now be efficiently prepared for ionization,structural imaging,orbital tomography,and more,enabling,for example,shooting of dynamic molecular ***,molecular alignment and orientation processes give rise to fundamental quantum and classical phenomena like quantum revivals,Anderson localization,and rotational echoes,just to mention a *** review recent progress on the visualization,coherent control,and applications of the rich dynamics of molecular rotational wave packets driven by laser pulses of various intensities,durations,and *** particular,we focus on the molecular unidirectional rotation and its visualization,the orientation of chiral molecules,and the three-dimensional orientation of asymmetric-top *** echoes are discussed as an example of nontrivial dynamics and detection of prepared molecular states.

关键词： ultrashort laser pulses alignment and orientation molecular unidirectional rotation rotational echoes

Observation of parity-time symmetry in time-division multiplexing pulsed optoelectronic oscillators within a single resonator

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Photonics research 2022年第8期10卷 1915-1923页

作者： HAO DING QIZHUANG CEN KUN XU MING LI YITANG DAI State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and TelecommunicationsBeijing 100876China State Key Laboratory on Integrated Optoelectronics Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China School of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of SciencesBeijing 100049China center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100190China Peng Cheng Laboratory Shenzhen 518052China

In recent years,parity-time(PT)symmetry in optoelectronic systems has been widely studied,due to its potential applications in lasers,sensors,topological networks,and other *** this paper,a time-division multiplexed pulsed optoelectronic oscillator(OEO)is proposed to study the dynamics of a PT symmetry *** microwave pulses are used to realize the PT symmetry in a single spatial resonator based on the temporal degrees of *** gain and loss of the microwave pulses and the coupling coefficient between them can then be *** first demonstrate the phase diagram from PT broken to PT symmetry in the OEO *** theoretically prove that the perturbation of a coupling-induced phase shift larger than(2π)×10^(-2)causes the disappearance of the PT *** this experiment,the perturbation is less than(2π)×0.5×10^(-2);thus,the phase transition of PT symmetry is *** addition,multipairs of PT-symmetry pulses indicate that pulsed OEO could be used to implement complex non-Hermitian Hamilton ***,it is confirmed that pulsed OEO is an excellent platform to explore the dynamics of PT symmetry and other non-Hermitian Hamiltonian systems.

关键词： optoelectronic resonator symmetry

Free-space local nonseparability dynamics of vector modes

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Photonics research 2021年第4期9卷 439-445页

作者： Xiao-Bo Hu Benjamin Perez-Garcia Valeria Rodríguez-Fajardo Raul I.Hernandez-Aranda Andrew Forbes Carmelo Rosales-Guzmán Wang Da-Heng Collaborative Innovation center Heilongjiang Provincial Key Laboratory of Quantum Manipulation and ControlHarbin University of Science and TechnologyHarbin 150080China Photonics and Mathematical Optics Group Tecnologico de MonterreyMonterrey 64849Mexico School of Physics University of the WitwatersrandJohannesburg 2050South Africa Centro de Investigaciones enÓptica A.C.Loma del Bosque 115Colonia Lomas del campestre37150 LeónGto.Mexico

One of the most prominent features of quantum entanglement is its invariability under local unitary transformations,which implies that the degree of entanglement or nonseparability remains constant during free-space propagation,true for both quantum and classically entangled *** we demonstrate an exception to this rule using a carefully engineered vectorial light field,and we study its nonseparability dynamics upon free-space *** show that the local nonseparability between the spatial and polarization degrees of freedom dramatically decays to zero while preserving the purity of the state and hence the global *** show this by numerical simulations and corroborate it *** results evince novel properties of classically entangled modes and point to the need for new measures of nonseparability for such vectorial fields,while paving the way for novel applications for customized structured light.

关键词： local dynamics quantum