Fourier light-field microscopy(FLFM)uses a microlens aray(MLA)to segment the Fourierplane of the microscopic objective lens to generate multiple two-dimensional perspective views,thereby reconstructing the threedimens...Fourier light-field microscopy(FLFM)uses a microlens aray(MLA)to segment the Fourierplane of the microscopic objective lens to generate multiple two-dimensional perspective views,thereby reconstructing the threedimensional(3D)structure of the sample using 3D deconvo-lution calculation without scanning.However,the resolution of FLFM is stil limited by dif-fraction,and furthermore,it is dependent on the aperture division.In order to improve itsresolution,a super-resolution opticai fuctuation Fourier light-field microscopy(SOFFLFM)wasproposed here,in which the super-resolution optical fluctuation imaging(SOFI)with the abilityof super-resolution was introduced into FLFM.SOFFLFM uses higher-order cumulants statis-tical analysis on an image sequence collected by FLFM,and then carries out 3D deconvolutioncalculation to reconstruct the 3D structure of the sample.The theoretical basis of SOFFLFM onimproving resolution was explained and then verified with the simulations.Simulation resultsdemonstrated that SOFFLFM improved the lateral and axial resolution by more than V2 and 2times in the second-and fourth-order accumulations,compared with that of FLFM.展开更多
The generation characteristics of nonlinear optical signals and their multi-dimensional modulation at micro-nano scale have become a prominent research area in nanophotonics,and also the key to developing various nove...The generation characteristics of nonlinear optical signals and their multi-dimensional modulation at micro-nano scale have become a prominent research area in nanophotonics,and also the key to developing various novel nonlinear photonics devices.In recent years,the demand for higher nonlinear conversion efficiency and device integration has led to the rapid progress of hybrid nonlinear metasurfaces composed of nanostructures and nonlinear materials.As a joint platform of stable wavefront modulation,nonlinear metasurface and efficient frequency conversion,hybrid nonlinear metasurfaces offer a splendid opportunity for developing the next-generation of multipurpose flat-optics devices.This article provides a comprehensive review of recent advances in hybrid nonlinear metasurfaces for light-field modulation.The advantages of hybrid systems are discussed from the perspectives of multifunctional light-field modulation,valleytronic modulation,and quantum technologies.Finally,the remaining challenges of hybrid metasurfaces are summarized and future developments are also prospected.展开更多
This work explores an alternative 3D geometry measurement method for non-cooperative spacecraft guiding navigation and proximity operations.From one snapshot of an unfocused light-field camera, the 3D point cloud of a...This work explores an alternative 3D geometry measurement method for non-cooperative spacecraft guiding navigation and proximity operations.From one snapshot of an unfocused light-field camera, the 3D point cloud of a non-cooperative spacecraft can be calculated from sub-aperture images with the epipolar plane image(EPI) based light-field rendering algorithm.A Chang'e-3 model(7.2 cm×5.6 cm×7.0 cm) is tested to validate the proposed technique.Three measurement distances(1.0 m, 1.2 m, 1.5 m) are considered to simulate different approaching stages.Measuring errors are quantified by comparing the light-field camera data with a high precision commercial laser scanner.The mean error distance for the three cases are 0.837 mm, 0.743 mm, and 0.973 mm respectively, indicating that the method can well reconstruct 3D geometry of a non-cooperative spacecraft with a densely distributed 3D point cloud and is thus promising in space-related missions.展开更多
Light-field fluorescence microscopy(LFM)is a powerful elegant compact method for long-term highspeed imaging of complex biological systems,such as neuron activities and rapid movements of organelles.LFM experiments ty...Light-field fluorescence microscopy(LFM)is a powerful elegant compact method for long-term highspeed imaging of complex biological systems,such as neuron activities and rapid movements of organelles.LFM experiments typically generate terabytes of image data and require a substantial amount of storage space.Some lossy compression algorithms have been proposed recently with good compression performance.However,since the specimen usually only tolerates low-power density illumination for longterm imaging with low phototoxicity,the image signal-to-noise ratio(SNR)is relatively low,which will cause the loss of some efficient position or intensity information using such lossy compression algorithms.Here,we propose a phase-space continuity-enhanced bzip2(PC-bzip2)lossless compression method for LFM data as a high-efficiency and open-source tool that combines graphics processing unit-based fast entropy judgment and multicore-CPU-based high-speed lossless compression.Our proposed method achieves almost 10%compression ratio improvement while keeping the capability of high-speed compression,compared with the original bzip2.We evaluated our method on fluorescence beads data and fluorescence staining cells data with different SNRs.Moreover,by introducing temporal continuity,our method shows the superior compression ratio on time series data of zebrafish blood vessels.展开更多
A concept of divergence angle of light beams(DALB)is proposed to analyze the depth of field(DOF)of a 3D light-field display system.The mathematical model between DOF and DALB is established,and the conclusion that DOF...A concept of divergence angle of light beams(DALB)is proposed to analyze the depth of field(DOF)of a 3D light-field display system.The mathematical model between DOF and DALB is established,and the conclusion that DOF and DALB are inversely proportional is drawn.To reduce DALB and generate clear depth perception,a triple composite aspheric lens structure with a viewing angle of 100°is designed and experimentally demonstrated.The DALB-constrained 3D light-field display system significantly improves the clarity of 3D images and also performs well in imaging at a 3D scene with a DOF over 30 cm.展开更多
The simplicity and low-cost way to improve qualitative and quantitative analytical performance has always been a crucial concern for laser-induced breakdown spectroscopy(LIBS),and many scientists have been engaged in ...The simplicity and low-cost way to improve qualitative and quantitative analytical performance has always been a crucial concern for laser-induced breakdown spectroscopy(LIBS),and many scientists have been engaged in this evolving research direction.In this review,we investigated an update on recent developments in light-field modulated operation in LIBS.It covered a brief description of LIBS,optical polarization,and beam shaping.Here,the optical polarization is divided into laser beam polariza-tion and plasma polarization.In addition,the methodology and develop-ment of light-field modulated LIBS were summarized and discussed.Finally,the existing problems with light-field modulated LIBS were presented,along with some of their own insights and the future direction of their development.This review will provide a guideline for LIBS researchers with basic knowledge,which is very useful in the signal opti-mization of LIBS research and applications.展开更多
The real-time measurement and reconstruction of three-dimensional temperature are essential when studying the combustion process inside a flame. In the proposed sectioned flame light field imaging model, flame section...The real-time measurement and reconstruction of three-dimensional temperature are essential when studying the combustion process inside a flame. In the proposed sectioned flame light field imaging model, flame sections are reconstructed based on the characteristics identified using the Lucy-Richardson or nearest neighbor filtering methods, or a joint method involving a combination of both, to improve on the accuracy of two-dimensional temperature reconstruction. Compared to the results of a previous work, the proposed method increases the resolution in the depth of field direction and the extraction of the flame temperature of all sections from the same height ensures the accuracy of the reconstructed temperature distribution across the cross-section of the flame. The relative error when compared to the actual flame is less than 10%. Thus, this approach allows the accurate estimation of the three-dimensional temperature distribution inside a flame, and enables the rapid and effective reconstruction of the three-dimensional temperature field.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11774242,61605127,61975131,62175166,and 61335001)the Shenzhen Science and Technology Planning Project(Grant Nos.JCYJ20210324094200001,JCYJ20200109105411133,and ZDSYS20210623092006020).
文摘Fourier light-field microscopy(FLFM)uses a microlens aray(MLA)to segment the Fourierplane of the microscopic objective lens to generate multiple two-dimensional perspective views,thereby reconstructing the threedimensional(3D)structure of the sample using 3D deconvo-lution calculation without scanning.However,the resolution of FLFM is stil limited by dif-fraction,and furthermore,it is dependent on the aperture division.In order to improve itsresolution,a super-resolution opticai fuctuation Fourier light-field microscopy(SOFFLFM)wasproposed here,in which the super-resolution optical fluctuation imaging(SOFI)with the abilityof super-resolution was introduced into FLFM.SOFFLFM uses higher-order cumulants statis-tical analysis on an image sequence collected by FLFM,and then carries out 3D deconvolutioncalculation to reconstruct the 3D structure of the sample.The theoretical basis of SOFFLFM onimproving resolution was explained and then verified with the simulations.Simulation resultsdemonstrated that SOFFLFM improved the lateral and axial resolution by more than V2 and 2times in the second-and fourth-order accumulations,compared with that of FLFM.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12274157,12274334,91850113,12021004,and 11904271)the Natural Science Foundation of Hubei Province of China(Grant No.2023AFA076)the Basic and Applied Basic Research Major Program of Guangdong Province of China(Grant No.2019B030302003)。
文摘The generation characteristics of nonlinear optical signals and their multi-dimensional modulation at micro-nano scale have become a prominent research area in nanophotonics,and also the key to developing various novel nonlinear photonics devices.In recent years,the demand for higher nonlinear conversion efficiency and device integration has led to the rapid progress of hybrid nonlinear metasurfaces composed of nanostructures and nonlinear materials.As a joint platform of stable wavefront modulation,nonlinear metasurface and efficient frequency conversion,hybrid nonlinear metasurfaces offer a splendid opportunity for developing the next-generation of multipurpose flat-optics devices.This article provides a comprehensive review of recent advances in hybrid nonlinear metasurfaces for light-field modulation.The advantages of hybrid systems are discussed from the perspectives of multifunctional light-field modulation,valleytronic modulation,and quantum technologies.Finally,the remaining challenges of hybrid metasurfaces are summarized and future developments are also prospected.
文摘This work explores an alternative 3D geometry measurement method for non-cooperative spacecraft guiding navigation and proximity operations.From one snapshot of an unfocused light-field camera, the 3D point cloud of a non-cooperative spacecraft can be calculated from sub-aperture images with the epipolar plane image(EPI) based light-field rendering algorithm.A Chang'e-3 model(7.2 cm×5.6 cm×7.0 cm) is tested to validate the proposed technique.Three measurement distances(1.0 m, 1.2 m, 1.5 m) are considered to simulate different approaching stages.Measuring errors are quantified by comparing the light-field camera data with a high precision commercial laser scanner.The mean error distance for the three cases are 0.837 mm, 0.743 mm, and 0.973 mm respectively, indicating that the method can well reconstruct 3D geometry of a non-cooperative spacecraft with a densely distributed 3D point cloud and is thus promising in space-related missions.
基金supported by the National Natural Science Foundation of China(Grant Nos.62371006,61931008,U21B2024,and 62071415)the National Key Research and Development Program of China(Grant No.2020YFB1406604)+2 种基金the Zhejiang Provincial Natural Science Foundation of China(Grant Nos.LDT23F01011F01,LDT23F01015F01,and LDT23F01014F01)the“Pioneer”and“Leading Goose”R&D Program of Zhejiang Province(Grant No.2022C01068)the China Postdoctoral Science Foundation(Grant Nos.2023TQ0006 and GZC20230057).
文摘Light-field fluorescence microscopy(LFM)is a powerful elegant compact method for long-term highspeed imaging of complex biological systems,such as neuron activities and rapid movements of organelles.LFM experiments typically generate terabytes of image data and require a substantial amount of storage space.Some lossy compression algorithms have been proposed recently with good compression performance.However,since the specimen usually only tolerates low-power density illumination for longterm imaging with low phototoxicity,the image signal-to-noise ratio(SNR)is relatively low,which will cause the loss of some efficient position or intensity information using such lossy compression algorithms.Here,we propose a phase-space continuity-enhanced bzip2(PC-bzip2)lossless compression method for LFM data as a high-efficiency and open-source tool that combines graphics processing unit-based fast entropy judgment and multicore-CPU-based high-speed lossless compression.Our proposed method achieves almost 10%compression ratio improvement while keeping the capability of high-speed compression,compared with the original bzip2.We evaluated our method on fluorescence beads data and fluorescence staining cells data with different SNRs.Moreover,by introducing temporal continuity,our method shows the superior compression ratio on time series data of zebrafish blood vessels.
基金supported by the National Key Research and Development Program of China(No.2021YFB3600504)the National Natural Science Foundation of China(Nos.62175015 and 62075016)。
文摘A concept of divergence angle of light beams(DALB)is proposed to analyze the depth of field(DOF)of a 3D light-field display system.The mathematical model between DOF and DALB is established,and the conclusion that DOF and DALB are inversely proportional is drawn.To reduce DALB and generate clear depth perception,a triple composite aspheric lens structure with a viewing angle of 100°is designed and experimentally demonstrated.The DALB-constrained 3D light-field display system significantly improves the clarity of 3D images and also performs well in imaging at a 3D scene with a DOF over 30 cm.
基金supported by the National Natural Science Foundation of China(No.61575030)the Scientific Research Foundation of Zhejiang A&F University,China(Nos.2022LFR030,2022LFR050,and 2024LFR047).
文摘The simplicity and low-cost way to improve qualitative and quantitative analytical performance has always been a crucial concern for laser-induced breakdown spectroscopy(LIBS),and many scientists have been engaged in this evolving research direction.In this review,we investigated an update on recent developments in light-field modulated operation in LIBS.It covered a brief description of LIBS,optical polarization,and beam shaping.Here,the optical polarization is divided into laser beam polariza-tion and plasma polarization.In addition,the methodology and develop-ment of light-field modulated LIBS were summarized and discussed.Finally,the existing problems with light-field modulated LIBS were presented,along with some of their own insights and the future direction of their development.This review will provide a guideline for LIBS researchers with basic knowledge,which is very useful in the signal opti-mization of LIBS research and applications.
基金supported by the National Natural Science Foundation of China (Grant No. 51776051)
文摘The real-time measurement and reconstruction of three-dimensional temperature are essential when studying the combustion process inside a flame. In the proposed sectioned flame light field imaging model, flame sections are reconstructed based on the characteristics identified using the Lucy-Richardson or nearest neighbor filtering methods, or a joint method involving a combination of both, to improve on the accuracy of two-dimensional temperature reconstruction. Compared to the results of a previous work, the proposed method increases the resolution in the depth of field direction and the extraction of the flame temperature of all sections from the same height ensures the accuracy of the reconstructed temperature distribution across the cross-section of the flame. The relative error when compared to the actual flame is less than 10%. Thus, this approach allows the accurate estimation of the three-dimensional temperature distribution inside a flame, and enables the rapid and effective reconstruction of the three-dimensional temperature field.
