Metasurfaces are ultrathin optical elements that are highly promising for constructing lightweight and compact optical systems.For their practical implementation,it is imperative to maximize the metasurface efficiency...Metasurfaces are ultrathin optical elements that are highly promising for constructing lightweight and compact optical systems.For their practical implementation,it is imperative to maximize the metasurface efficiency.Topology optimization provides a pathway for pushing the limits of metasurface efficiency;however,topology optimization methods have been limited to the design of microscale devices due to the extensive computational resources that are required.We introduce a new strategy for optimizing large-area metasurfaces in a computationally efficient manner.By stitching together individually optimized sections of the metasurface,we can reduce the computational complexity of the optimization from high-polynomial to linear.As a proof of concept,we design and experimentally demonstrate large-area,high-numerical-aperture silicon metasurface lenses with focusing efficiencies exceeding 90%.These concepts can be generalized to the design of multifunctional,broadband diffractive optical devices and will enable the implementation of large-area,high-performance metasurfaces in practical optical systems.展开更多
The growing maturity of nanofabrication has ushered massive sophisticated optical structures available on a photonic chip.The integration of subwavelength-structured metasurfaces and metamaterials on the canonical bui...The growing maturity of nanofabrication has ushered massive sophisticated optical structures available on a photonic chip.The integration of subwavelength-structured metasurfaces and metamaterials on the canonical building block of optical waveguides is gradually reshaping the landscape of photonic integrated circuits,giving rise to numerous metawaveguides with unprecedented strength in controlling guided electromagnetic waves.Here,we review recent advances in meta-structured waveguides that synergize various functional subwavelength photonic architectures with diverse waveguide platforms,such as dielectric or plasmonic waveguides and optical fibers.Foundational results and representative applications are comprehensively summarized.Brief physical models with explicit design tutorials,either physical intuition-based design methods or computer algorithms-based inverse designs,are cataloged as well.We highlight how meta-optics can infuse new degrees of freedom to waveguide-based devices and systems,by enhancing light-matter interaction strength to drastically boost device performance,or offering a versatile designer media for manipulating light in nanoscale to enable novel functionalities.We further discuss current challenges and outline emerging opportunities of this vibrant field for various applications in photonic integrated circuits,biomedical sensing,artificial intelligence and beyond.展开更多
Chemical looping combustion （CLC） and chemical looping reforming （CLR） are innovative technologies for clean and efficient hydrocarbon conversion into power, fuels, and chemicals through cyclic redox reac- tions. ...Chemical looping combustion （CLC） and chemical looping reforming （CLR） are innovative technologies for clean and efficient hydrocarbon conversion into power, fuels, and chemicals through cyclic redox reac- tions. Metal oxide materials play an essential role in the chemical looping redox processes. During reduc- tion, the oxygen carriers donate the required amount of oxygen ions for hydrocarbon conversion and product synthesis. In the oxidation step, the depleted metal oxide oxygen carriers are replenished with molecular oxygen from the air while heat is released. In recent years, there have been significant advances in oxygen carrier materials for various chemical looping applications. Among these metal oxide materials, iron-based oxygen carriers are attractive due to their high oxygen-carrying capacity, cost ben- efits, and versatility in applications for chemical looping reactions. Their reactivity can also be enhanced via structural design and modification. This review discusses recent advances in the development of oxy- gen carrier materials and the mechanisms of hydrocarbon conversion over these materials. These advances will facilitate the development of oxygen carrier materials for more efficient chemical looping technology applications.展开更多
The Jiangmen Underground Neutrino Observatory(JUNO)is a large liquid scintillator detector designed to explore many topics in fundamental physics.In this study,the potential of searching for proton decay in the p→νK...The Jiangmen Underground Neutrino Observatory(JUNO)is a large liquid scintillator detector designed to explore many topics in fundamental physics.In this study,the potential of searching for proton decay in the p→νK^(+)mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification.Moreover,the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals.Based on these advantages,the detection efficiency for the proton decay via p→νK^(+)is 36.9%±4.9%with a background level of 0.2±0.05(syst)±0.2(stat)events after 10 years of data collection.The estimated sensitivity based on 200 kton-years of exposure is 9.6×1033 years,which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies.展开更多
JUNO is a multi-purpose neutrino observatory under construction in the south of China.This publication presents new sensitivity estimates for the measurement of the △m_(31)^(2),△m_(21)^(2),sin^(2)θ_(12),and sin^(2)...JUNO is a multi-purpose neutrino observatory under construction in the south of China.This publication presents new sensitivity estimates for the measurement of the △m_(31)^(2),△m_(21)^(2),sin^(2)θ_(12),and sin^(2)θ_(13) oscillation parameters using reactor antineutrinos,which is one of the primary physics goals of the experiment.The sensitivities are obtained using the best knowledge available to date on the location and overburden of the experimental site,the nuclear reactors in the surrounding area and beyond,the detector response uncertainties,and the reactor antineutrino spectral shape constraints expected from the TAO satellite detector.It is found that the △m_(21)^(2) and sin^(2)θ_(12) oscillation parameters will be determined to 0.5%precision or better in six years of data collection.In the same period,the △m_(31)^(2) parameter will be determined to about 0.2%precision for each mass ordering hypothesis.The new precision represents approximately an order of magnitude improvement over existing constraints for these three parameters.展开更多
Long-range and fast transport of coherent excitons is important for the development of high-speed excitonic circuits and quantum computing applications.However,most of these coherent excitons have only been observed i...Long-range and fast transport of coherent excitons is important for the development of high-speed excitonic circuits and quantum computing applications.However,most of these coherent excitons have only been observed in some low-dimensional semiconductors when coupled with cavities,as there are large inhomogeneous broadening and dephasing effects on the transport of excitons in their native states in materials.Here,by confining coherent excitons at the 2D quantum limit,we first observed molecular aggregation-enabled‘supertransport’of excitons in atomically thin two-dimensional(2D)organic semiconductors between coherent states,with a measured high effective exciton diffusion coefficient of ~346.9 cm^(2)/s at room temperature.This value is one to several orders of magnitude higher than the values reported for other organic molecular aggregates and low-dimensional inorganic materials.Without coupling to any optical cavities,the monolayer pentacene sample,a very clean 2D quantum system(~1.2 nm thick)with high crystallinity(J-type aggregation)and minimal interfacial states,showed superradiant emission from Frenkel excitons,which was experimentally confirmed by the temperature-dependent photoluminescence(PL)emission,highly enhanced radiative decay rate,significantly narrowed PL peak width and strongly directional in-plane emission.The coherence in monolayer pentacene samples was observed to be delocalised over~135 molecules,which is significantly larger than the values(a few molecules)observed for other organic thin films.In addition,the supertransport of excitons in monolayer pentacene samples showed highly anisotropic behaviour.Our results pave the way for the development of future high-speed excitonic circuits,fast OLEDs,and other optoelectronic devices.展开更多
Multifunctional metasurfaces based on wavelength-decoupled supercells are experimentally demonstrated,enabling new regimes of optical control for arbitrary orthogonal polarizations at different wavelengths.
We introduce an imaging system that can simultaneously record complete Mueller polarization responses for a set of wavelength channels in a single image capture.The division-of-focal-plane concept combines a multiplex...We introduce an imaging system that can simultaneously record complete Mueller polarization responses for a set of wavelength channels in a single image capture.The division-of-focal-plane concept combines a multiplexed illumination scheme based on Fourier optics together with an integrated telescopic light-field imaging system.Polarization-resolved imaging is achieved using broadband nanostructured plasmonic polarizers as functional pinhole apertures.The recording of polarization and wavelength information on the image sensor is highly interpretable.We also develop a calibration approach based on a customized neural network architecture that can produce calibrated measurements in real-time.As a proof-of-concept demonstration,we use our calibrated system to accurately reconstruct a thin film thickness map from a four-inch wafer.We anticipate that our concept will have utility in metrology,machine vision,computational imaging,and optical computing platforms.展开更多
Epidermal electronic systems feature physical properties that approximate those of the skin,to enable intimate,long-lived skin interfaces for physiological measurements,human–machine interfaces and other applications...Epidermal electronic systems feature physical properties that approximate those of the skin,to enable intimate,long-lived skin interfaces for physiological measurements,human–machine interfaces and other applications that cannot be addressed by wearable hardware that is commercially available today.A primary challenge is power supply;the physical bulk,large mass and high mechanical modulus associated with conventional battery technologies can hinder efforts to achieve epidermal characteristics,and near-field power transfer schemes offer only a limited operating distance.Here we introduce an epidermal,farfield radio frequency(RF)power harvester built using a modularized collection of ultrathin antennas,rectifiers and voltage doublers.These components,separately fabricated and tested,can be integrated together via methods involving soft contact lamination.Systematic studies of the individual components and the overall performance in various dielectric environments highlight the key operational features of these systems and strategies for their optimization.The results suggest robust capabilities for battery-free RF power,with relevance to many emerging epidermal technologies.展开更多
Alloderm was the first acellular dermal matrix used and remains a popular choice among plastic surgeons.However,while the overall surgical outcome of breast reconstruction using alloderm has been a success,the economi...Alloderm was the first acellular dermal matrix used and remains a popular choice among plastic surgeons.However,while the overall surgical outcome of breast reconstruction using alloderm has been a success,the economic burden on the health care system makes it a subject of frequent re-evaluations in cost-effectiveness.Prompted by the high price of$3,700 USD for a 6 cm×16 cm area,our group proposes the meshing of AlloDerm to decrease the total amount needed for breast reconstruction,while achieving comparable surgical outcomes as using unmeshed alloderm.展开更多
基金supported by the U.S.Air Force under Award Number FA9550-18-1-0070the Office of Naval Research under Award Number N00014-16-1-2630+3 种基金the David and Lucile Packard Foundationsupported by the National Science Foundation(NSF)through an NSF Graduate Research Fellowshipsupported by the Department of Defense(DoD)through an NDSEG Research Fellowshipsupported by the National Science Foundation as part of the National Nanotechnology Coordinated Infrastructure under award ECCS-1542152.
文摘Metasurfaces are ultrathin optical elements that are highly promising for constructing lightweight and compact optical systems.For their practical implementation,it is imperative to maximize the metasurface efficiency.Topology optimization provides a pathway for pushing the limits of metasurface efficiency;however,topology optimization methods have been limited to the design of microscale devices due to the extensive computational resources that are required.We introduce a new strategy for optimizing large-area metasurfaces in a computationally efficient manner.By stitching together individually optimized sections of the metasurface,we can reduce the computational complexity of the optimization from high-polynomial to linear.As a proof of concept,we design and experimentally demonstrate large-area,high-numerical-aperture silicon metasurface lenses with focusing efficiencies exceeding 90%.These concepts can be generalized to the design of multifunctional,broadband diffractive optical devices and will enable the implementation of large-area,high-performance metasurfaces in practical optical systems.
基金Q.X.acknowledges support from National Natural Science Foundation of China(Grants Nos.62075113,61675114)S.S.is supported by National Key Research and Development Program of China(Nos.2020YFA0710101,2017YFA0303504)+8 种基金National Natural Science Foundation of China(11874118)Natural Science Foundation of Shanghai(18ZR1403400,20JC1414601)Fudan University-CIOMP Joint Fund(No.FC2018-008)M.Z.is supported by National Natural Science Foundation of China(61775069,61635004)J.A.F.is supported by Office of Naval Research(under Award No.N00014-20-1-2105)ARPA-E(under Award No.DE-AR0001212)Z.X.and X.Y.acknowledge support from National Natural Science Foundation of China(61935013,U1701661,61975133)the Natural Science Foundation of Guangdong Province(2020A1515011185)the Science and Technology Innovation Commission of Shenzhen(JCYJ20180507182035270,JCYJ20200109114018750).
文摘The growing maturity of nanofabrication has ushered massive sophisticated optical structures available on a photonic chip.The integration of subwavelength-structured metasurfaces and metamaterials on the canonical building block of optical waveguides is gradually reshaping the landscape of photonic integrated circuits,giving rise to numerous metawaveguides with unprecedented strength in controlling guided electromagnetic waves.Here,we review recent advances in meta-structured waveguides that synergize various functional subwavelength photonic architectures with diverse waveguide platforms,such as dielectric or plasmonic waveguides and optical fibers.Foundational results and representative applications are comprehensively summarized.Brief physical models with explicit design tutorials,either physical intuition-based design methods or computer algorithms-based inverse designs,are cataloged as well.We highlight how meta-optics can infuse new degrees of freedom to waveguide-based devices and systems,by enhancing light-matter interaction strength to drastically boost device performance,or offering a versatile designer media for manipulating light in nanoscale to enable novel functionalities.We further discuss current challenges and outline emerging opportunities of this vibrant field for various applications in photonic integrated circuits,biomedical sensing,artificial intelligence and beyond.
文摘Chemical looping combustion （CLC） and chemical looping reforming （CLR） are innovative technologies for clean and efficient hydrocarbon conversion into power, fuels, and chemicals through cyclic redox reac- tions. Metal oxide materials play an essential role in the chemical looping redox processes. During reduc- tion, the oxygen carriers donate the required amount of oxygen ions for hydrocarbon conversion and product synthesis. In the oxidation step, the depleted metal oxide oxygen carriers are replenished with molecular oxygen from the air while heat is released. In recent years, there have been significant advances in oxygen carrier materials for various chemical looping applications. Among these metal oxide materials, iron-based oxygen carriers are attractive due to their high oxygen-carrying capacity, cost ben- efits, and versatility in applications for chemical looping reactions. Their reactivity can also be enhanced via structural design and modification. This review discusses recent advances in the development of oxy- gen carrier materials and the mechanisms of hydrocarbon conversion over these materials. These advances will facilitate the development of oxygen carrier materials for more efficient chemical looping technology applications.
基金supported by the Chinese Academy of Sciencesthe National Key R&D Program of China+22 种基金the CAS Center for Excellence in Particle PhysicsWuyi Universitythe Tsung-Dao Lee Institute of Shanghai Jiao Tong University in Chinathe Institut National de Physique Nucléaire et de Physique de Particules (IN2P3) in Francethe Istituto Nazionale di Fisica Nucleare (INFN) in Italythe Italian-Chinese collaborative research program MAECI-NSFCthe Fond de la Recherche Scientifique (F.R.S-FNRS)FWO under the "Excellence of Science-EOS" in Belgiumthe Conselho Nacional de Desenvolvimento Científico e Tecnològico in Brazilthe Agencia Nacional de Investigacion y Desarrollo in Chilethe Charles University Research Centrethe Ministry of Education,Youth,and Sports in Czech Republicthe Deutsche Forschungsgemeinschaft (DFG)the Helmholtz Associationthe Cluster of Excellence PRISMA+ in Germanythe Joint Institute of Nuclear Research (JINR)Lomonosov Moscow State University in Russiathe joint Russian Science Foundation (RSF)National Natural Science Foundation of China (NSFC) research programthe MOST and MOE in Taiwan,Chinathe Chulalongkorn UniversitySuranaree University of Technology in Thailandthe University of California at Irvine in USA
文摘The Jiangmen Underground Neutrino Observatory(JUNO)is a large liquid scintillator detector designed to explore many topics in fundamental physics.In this study,the potential of searching for proton decay in the p→νK^(+)mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification.Moreover,the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals.Based on these advantages,the detection efficiency for the proton decay via p→νK^(+)is 36.9%±4.9%with a background level of 0.2±0.05(syst)±0.2(stat)events after 10 years of data collection.The estimated sensitivity based on 200 kton-years of exposure is 9.6×1033 years,which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies.
基金Supported by the Chinese Academy of Sciencesthe National Key R&D Program of China+18 种基金the CAS Center for Excellence in Particle Physics,Wuyi Universitythe Tsung-Dao Lee Institute of Shanghai Jiao Tong University in Chinathe Institut National de Physique Nucléaire et de Physique de Particules(IN2P3)in Francethe Istituto Nazionale di Fisica Nucleare(INFN)in Italythe Italian-Chinese collaborative research program MAECI-NSFCthe Fond de la Recherche Scientifique(F.R.S-FNRS)FWO under the“Excellence of Science-EOS in Belgium”the Conselho Nacional de Desenvolvimento Científico e Tecnològico in Brazilthe Agencia Nacional de Investigacion y Desarrollo and ANID-Millennium Science Initiative Program-ICN2019_044 in Chilethe Charles University Research Centre and the Ministry of Education,Youth,and Sports in Czech Republicthe Deutsche Forschungsgemeinschaft(DFG)the Helmholtz Associationthe Cluster of Excellence PRISMA+in Germanythe Joint Institute of Nuclear Research(JINR)and Lomonosov Moscow State University in Russiathe joint Russian Science Foundation(RSF)National Natural Science Foundation of China(NSFC)research programthe MOST and MOE in Taiwanthe Chulalongkorn University and Suranaree University of Technology in Thailand,University of California at Irvinethe National Science Foundation in USA。
文摘JUNO is a multi-purpose neutrino observatory under construction in the south of China.This publication presents new sensitivity estimates for the measurement of the △m_(31)^(2),△m_(21)^(2),sin^(2)θ_(12),and sin^(2)θ_(13) oscillation parameters using reactor antineutrinos,which is one of the primary physics goals of the experiment.The sensitivities are obtained using the best knowledge available to date on the location and overburden of the experimental site,the nuclear reactors in the surrounding area and beyond,the detector response uncertainties,and the reactor antineutrino spectral shape constraints expected from the TAO satellite detector.It is found that the △m_(21)^(2) and sin^(2)θ_(12) oscillation parameters will be determined to 0.5%precision or better in six years of data collection.In the same period,the △m_(31)^(2) parameter will be determined to about 0.2%precision for each mass ordering hypothesis.The new precision represents approximately an order of magnitude improvement over existing constraints for these three parameters.
基金funding support from ANU PhD student scholarship,China Scholarship Council,Australian Research Council(ARC,numbers DE140100805 and DP180103238)ARC Centre of Excellence in Future Low-Energy Electronics Technologies(project number CE170100039)ARC Centre of Excellence in Quantum Computation and Communication Technology(project number CE170100012).
文摘Long-range and fast transport of coherent excitons is important for the development of high-speed excitonic circuits and quantum computing applications.However,most of these coherent excitons have only been observed in some low-dimensional semiconductors when coupled with cavities,as there are large inhomogeneous broadening and dephasing effects on the transport of excitons in their native states in materials.Here,by confining coherent excitons at the 2D quantum limit,we first observed molecular aggregation-enabled‘supertransport’of excitons in atomically thin two-dimensional(2D)organic semiconductors between coherent states,with a measured high effective exciton diffusion coefficient of ~346.9 cm^(2)/s at room temperature.This value is one to several orders of magnitude higher than the values reported for other organic molecular aggregates and low-dimensional inorganic materials.Without coupling to any optical cavities,the monolayer pentacene sample,a very clean 2D quantum system(~1.2 nm thick)with high crystallinity(J-type aggregation)and minimal interfacial states,showed superradiant emission from Frenkel excitons,which was experimentally confirmed by the temperature-dependent photoluminescence(PL)emission,highly enhanced radiative decay rate,significantly narrowed PL peak width and strongly directional in-plane emission.The coherence in monolayer pentacene samples was observed to be delocalised over~135 molecules,which is significantly larger than the values(a few molecules)observed for other organic thin films.In addition,the supertransport of excitons in monolayer pentacene samples showed highly anisotropic behaviour.Our results pave the way for the development of future high-speed excitonic circuits,fast OLEDs,and other optoelectronic devices.
文摘Multifunctional metasurfaces based on wavelength-decoupled supercells are experimentally demonstrated,enabling new regimes of optical control for arbitrary orthogonal polarizations at different wavelengths.
基金supported by the Samsung Global Outreach Program and the Office of Naval Research under Award Number N00014-16-1-2630EW was supported by the Stanford Graduate Fellowship.Fabrication was performed in part at the Stanford Nanofabrication Facility(SNF)and the Stanford Nano Shared Facilities(SNSF)supported by the National Science Foundation as part of the National Nanotechnology Coordinated Infrastructure under award ECCS-1542152.
文摘We introduce an imaging system that can simultaneously record complete Mueller polarization responses for a set of wavelength channels in a single image capture.The division-of-focal-plane concept combines a multiplexed illumination scheme based on Fourier optics together with an integrated telescopic light-field imaging system.Polarization-resolved imaging is achieved using broadband nanostructured plasmonic polarizers as functional pinhole apertures.The recording of polarization and wavelength information on the image sensor is highly interpretable.We also develop a calibration approach based on a customized neural network architecture that can produce calibrated measurements in real-time.As a proof-of-concept demonstration,we use our calibrated system to accurately reconstruct a thin film thickness map from a four-inch wafer.We anticipate that our concept will have utility in metrology,machine vision,computational imaging,and optical computing platforms.
基金XF and YM acknowledge the support from the National Basic Research Program of China(Grant No.2015CB351900)the National Natural Science Foundation of China(Grant Nos.11402135 and 11320101001).
文摘Epidermal electronic systems feature physical properties that approximate those of the skin,to enable intimate,long-lived skin interfaces for physiological measurements,human–machine interfaces and other applications that cannot be addressed by wearable hardware that is commercially available today.A primary challenge is power supply;the physical bulk,large mass and high mechanical modulus associated with conventional battery technologies can hinder efforts to achieve epidermal characteristics,and near-field power transfer schemes offer only a limited operating distance.Here we introduce an epidermal,farfield radio frequency(RF)power harvester built using a modularized collection of ultrathin antennas,rectifiers and voltage doublers.These components,separately fabricated and tested,can be integrated together via methods involving soft contact lamination.Systematic studies of the individual components and the overall performance in various dielectric environments highlight the key operational features of these systems and strategies for their optimization.The results suggest robust capabilities for battery-free RF power,with relevance to many emerging epidermal technologies.
文摘Alloderm was the first acellular dermal matrix used and remains a popular choice among plastic surgeons.However,while the overall surgical outcome of breast reconstruction using alloderm has been a success,the economic burden on the health care system makes it a subject of frequent re-evaluations in cost-effectiveness.Prompted by the high price of$3,700 USD for a 6 cm×16 cm area,our group proposes the meshing of AlloDerm to decrease the total amount needed for breast reconstruction,while achieving comparable surgical outcomes as using unmeshed alloderm.
