With the same level of measurement accuracy,more portable and miniaturized measurement systems will have greater advantages,providing users with more flexible and convenient measurement solutions.Here,we introduce a n...With the same level of measurement accuracy,more portable and miniaturized measurement systems will have greater advantages,providing users with more flexible and convenient measurement solutions.Here,we introduce a new type of digital image correlation(DIC)system that incorporates a binocular meta-lens,featuring a simple and compact configuration.Meta-lens is one of the promising flat optical imaging devices that are ultra-thin,customizable,and well-suited for use in confined spaces.We evaluated this binocular meta-lens based DIC(BM-DIC)system through classic in-plane and out-of-plane translation tests,followed by a bending test on a helicopter wing model to capture 3D displacement and deformation fields.For in-plane translations,the system achieved high precision with a standard deviation(σ)below 2μm.Despite a small baseline of 4 mm,the system maintained aσof approximately 32μm for out-of-plane translations.Comparative analysis with conventional dual-camera stereo DIC systems showed that the BM-DIC system maintains an acceptable relative error margin of about 1%in measured strain fields despite a 75-fold reduction in baseline length.This research demonstrates the integration of DIC techniques with advanced meta-lens technology,indicating substantial potential to enhance the capabilities of DIC technology in experimental solid mechanics.展开更多
Meta-lens are a new type of planar optical element that can flexibly manipulate the phase, polarization and amplitude of the beam, and are currently receiving a great deal of attention as they are easier to process an...Meta-lens are a new type of planar optical element that can flexibly manipulate the phase, polarization and amplitude of the beam, and are currently receiving a great deal of attention as they are easier to process and manufacture. Off-axis meta-lens are a special type of meta-lens with a certain degree of dispersion that can be used as a beam-splitting element, providing a unique and feasible way to realize micro-miniature instruments. We analyze the effects of different numerical apertures and off-axis angles on the spectral resolution, focusing efficiency and simulation results of off-axis meta-lens to provide ideas for subsequent research and application of off-axis meta-lens. A number of off-axis meta-lens with parameters NA = 0.408 α = 13°, NA = 0.18 α = 13°<sup></sup> and NA = 0.408 α = 20° were simulated through Lumerical software. The results show that the off-axis angle is related to the resolution;the larger the angle, the better the spectral resolution but the lower the focusing efficiency;when the numerical aperture is smaller, the smaller the coverage of the phase distribution, which will lead to a larger deviation between simulation and theory. The designer needs to balance the numerical aperture, off-axis angle and other parameters reasonably according to the requirements in order to achieve the desired effect. The findings of this study have important reference values for the theoretical analysis of off-axis meta-lens and the design of parameters in practical applications. .展开更多
The increasing popularity of the metaverse has led to a growing interest and market size in spatial computing from both academia and industry.Developing portable and accurate imaging and depth sensing systems is cruci...The increasing popularity of the metaverse has led to a growing interest and market size in spatial computing from both academia and industry.Developing portable and accurate imaging and depth sensing systems is crucial for advancing next-generation virtual reality devices.This work demonstrates an intelligent,lightweight,and compact edge-enhanced depth perception system that utilizes a binocular meta-lens for spatial computing.The miniaturized system comprises a binocular meta-lens,a 532 nm filter,and a CMOS sensor.For disparity computation,we propose a stereo-matching neural network with a novel H-Module.The H-Module incorporates an attention mechanism into the Siamese network.The symmetric architecture,with cross-pixel interaction and cross-view interaction,enables a more comprehensive analysis of contextual information in stereo images.Based on spatial intensity discontinuity,the edge enhancement eliminates illposed regions in the image where ambiguous depth predictions may occur due to a lack of texture.With the assistance of deep learning,our edge-enhanced system provides prompt responses in less than 0.15 seconds.This edge-enhanced depth perception meta-lens imaging system will significantly contribute to accurate 3D scene modeling,machine vision,autonomous driving,and robotics development.展开更多
Large-element-spacing(LES)antenna arrays present an attractive proposition with their cost-effectiveness and sim-plified structures.However,they often encounter the challenge of high-level grating lobes.This paper pro...Large-element-spacing(LES)antenna arrays present an attractive proposition with their cost-effectiveness and sim-plified structures.However,they often encounter the challenge of high-level grating lobes.This paper proposes a novel meta-lens methodology to effectively address the grating lobe issue in fixed-beam LES arrays.The proposed approach involves strategically positioning a meta-lens above the LES arrays at a suitable vertical distance.This setup enables precise manipulation and compen-sation of the near-field phase,resulting in the suppression or elimination of grating lobes without introducing additional design com-plexity.Comprehensive theoretical analyses,meticulous design calculations employing efficient numerical methods,rigorous field simulations,and practical experiments are conducted.The results demonstrate that our meta-lens solution achieves significant grating-lobe suppressions and substantial gain enhancements with only a marginal increase in system profile or volume.The proposed meta-lens approach is versatile and applicable to various LES antenna arrays,including sparse/thinned arrays,regardless of their size,element spacing,and configuration(uniform or non-uniform,periodic or aperiodic).展开更多
目的评价多区正向离焦(DIMS)镜片对近视儿童等效球镜度(SE)和眼轴长度(AL)的抑制效果。方法检索中国知网、万方数据、维普网、中国生物医学文献数据库、PubMed、Embase、Cochrane Library、Web of Science从建库至2023年6月报道的DIMS...目的评价多区正向离焦(DIMS)镜片对近视儿童等效球镜度(SE)和眼轴长度(AL)的抑制效果。方法检索中国知网、万方数据、维普网、中国生物医学文献数据库、PubMed、Embase、Cochrane Library、Web of Science从建库至2023年6月报道的DIMS镜片干预近视进展的临床研究,试验组采用DIMS镜片进行干预,对照组配戴单焦眼镜(SVL)。由2位研究人员独立依据纳入和排除标准进行文献检索、筛选和数据提取。按照Cochrane手册要求进行文献质量及偏倚风险评价。使用Revman5.4软件完成meta分析。结果共计7项应用DIMS镜片干预近视进展的临床研究被纳入分析。7项研究提供了完整SE数据用于分析,DIMS组和SVL组的样本量分别为1164眼和1140眼;5项研究提供了完整AL数据用于分析,DIMS组和SVL组的样本量分别为339眼和315眼;DIMS组与SVL组间SE和AL差异均有统计学意义(SE:WMD=0.40,95%CI:0.32~0.47,P<0.001;AL:WMD=-0.14,95%CI:-0.17~-0.11,P<0.001),DIMS镜片可以有效延缓近视患者SE进展和AL增长速度。结论DIMS镜片可在一定程度上延缓SE进展和AL增长速度。展开更多
基金financial support from the Research Grants Council of the Hong Kong Special Administrative Region,China(Project No.C5031-22G,CityU11310522,CityU11300123)City University of Hong Kong(Project No.9610628)+5 种基金National Natural Science Foundation of China(NSFC)(12172222,12302368,22227901)National Science and Technology Major Project of China(J2019-V-0004-0095)Science Center for Gas Turbine Project(2023-B-V-002-001)Aeronautical Science Foundation of China(20230046057018)China Postdoctoral Science Foundation(2023M742231)Postdoctoral Fellowship Program of CPSF(GZC20231561。
文摘With the same level of measurement accuracy,more portable and miniaturized measurement systems will have greater advantages,providing users with more flexible and convenient measurement solutions.Here,we introduce a new type of digital image correlation(DIC)system that incorporates a binocular meta-lens,featuring a simple and compact configuration.Meta-lens is one of the promising flat optical imaging devices that are ultra-thin,customizable,and well-suited for use in confined spaces.We evaluated this binocular meta-lens based DIC(BM-DIC)system through classic in-plane and out-of-plane translation tests,followed by a bending test on a helicopter wing model to capture 3D displacement and deformation fields.For in-plane translations,the system achieved high precision with a standard deviation(σ)below 2μm.Despite a small baseline of 4 mm,the system maintained aσof approximately 32μm for out-of-plane translations.Comparative analysis with conventional dual-camera stereo DIC systems showed that the BM-DIC system maintains an acceptable relative error margin of about 1%in measured strain fields despite a 75-fold reduction in baseline length.This research demonstrates the integration of DIC techniques with advanced meta-lens technology,indicating substantial potential to enhance the capabilities of DIC technology in experimental solid mechanics.
文摘Meta-lens are a new type of planar optical element that can flexibly manipulate the phase, polarization and amplitude of the beam, and are currently receiving a great deal of attention as they are easier to process and manufacture. Off-axis meta-lens are a special type of meta-lens with a certain degree of dispersion that can be used as a beam-splitting element, providing a unique and feasible way to realize micro-miniature instruments. We analyze the effects of different numerical apertures and off-axis angles on the spectral resolution, focusing efficiency and simulation results of off-axis meta-lens to provide ideas for subsequent research and application of off-axis meta-lens. A number of off-axis meta-lens with parameters NA = 0.408 α = 13°, NA = 0.18 α = 13°<sup></sup> and NA = 0.408 α = 20° were simulated through Lumerical software. The results show that the off-axis angle is related to the resolution;the larger the angle, the better the spectral resolution but the lower the focusing efficiency;when the numerical aperture is smaller, the smaller the coverage of the phase distribution, which will lead to a larger deviation between simulation and theory. The designer needs to balance the numerical aperture, off-axis angle and other parameters reasonably according to the requirements in order to achieve the desired effect. The findings of this study have important reference values for the theoretical analysis of off-axis meta-lens and the design of parameters in practical applications. .
基金supports from the Research Grants Council of the Hong Kong Special Administrative Region,China[Project No.C5031-22GCityU11310522+3 种基金CityU11300123]the Department of Science and Technology of Guangdong Province[Project No.2020B1515120073]City University of Hong Kong[Project No.9610628]JST CREST(Grant No.JPMJCR1904).
文摘The increasing popularity of the metaverse has led to a growing interest and market size in spatial computing from both academia and industry.Developing portable and accurate imaging and depth sensing systems is crucial for advancing next-generation virtual reality devices.This work demonstrates an intelligent,lightweight,and compact edge-enhanced depth perception system that utilizes a binocular meta-lens for spatial computing.The miniaturized system comprises a binocular meta-lens,a 532 nm filter,and a CMOS sensor.For disparity computation,we propose a stereo-matching neural network with a novel H-Module.The H-Module incorporates an attention mechanism into the Siamese network.The symmetric architecture,with cross-pixel interaction and cross-view interaction,enables a more comprehensive analysis of contextual information in stereo images.Based on spatial intensity discontinuity,the edge enhancement eliminates illposed regions in the image where ambiguous depth predictions may occur due to a lack of texture.With the assistance of deep learning,our edge-enhanced system provides prompt responses in less than 0.15 seconds.This edge-enhanced depth perception meta-lens imaging system will significantly contribute to accurate 3D scene modeling,machine vision,autonomous driving,and robotics development.
基金National Natural Science Foundation of China(Grant Nos.62071187,62071125,and 62301162)Natural Science Foundation of Fujian Province,China(Grant No.2023J01058)+1 种基金Industry-Education Cooperation Project in Fujian Province,China(Grant No.2022H6018)Fujian Province Major Special Topic Project(Grant No.2022HZ026007).
文摘Large-element-spacing(LES)antenna arrays present an attractive proposition with their cost-effectiveness and sim-plified structures.However,they often encounter the challenge of high-level grating lobes.This paper proposes a novel meta-lens methodology to effectively address the grating lobe issue in fixed-beam LES arrays.The proposed approach involves strategically positioning a meta-lens above the LES arrays at a suitable vertical distance.This setup enables precise manipulation and compen-sation of the near-field phase,resulting in the suppression or elimination of grating lobes without introducing additional design com-plexity.Comprehensive theoretical analyses,meticulous design calculations employing efficient numerical methods,rigorous field simulations,and practical experiments are conducted.The results demonstrate that our meta-lens solution achieves significant grating-lobe suppressions and substantial gain enhancements with only a marginal increase in system profile or volume.The proposed meta-lens approach is versatile and applicable to various LES antenna arrays,including sparse/thinned arrays,regardless of their size,element spacing,and configuration(uniform or non-uniform,periodic or aperiodic).
文摘目的评价多区正向离焦(DIMS)镜片对近视儿童等效球镜度(SE)和眼轴长度(AL)的抑制效果。方法检索中国知网、万方数据、维普网、中国生物医学文献数据库、PubMed、Embase、Cochrane Library、Web of Science从建库至2023年6月报道的DIMS镜片干预近视进展的临床研究,试验组采用DIMS镜片进行干预,对照组配戴单焦眼镜(SVL)。由2位研究人员独立依据纳入和排除标准进行文献检索、筛选和数据提取。按照Cochrane手册要求进行文献质量及偏倚风险评价。使用Revman5.4软件完成meta分析。结果共计7项应用DIMS镜片干预近视进展的临床研究被纳入分析。7项研究提供了完整SE数据用于分析,DIMS组和SVL组的样本量分别为1164眼和1140眼;5项研究提供了完整AL数据用于分析,DIMS组和SVL组的样本量分别为339眼和315眼;DIMS组与SVL组间SE和AL差异均有统计学意义(SE:WMD=0.40,95%CI:0.32~0.47,P<0.001;AL:WMD=-0.14,95%CI:-0.17~-0.11,P<0.001),DIMS镜片可以有效延缓近视患者SE进展和AL增长速度。结论DIMS镜片可在一定程度上延缓SE进展和AL增长速度。
