Nonlinear wavefront shaping is crucial for advancing optical technologies,enabling applications in optical computation,information processing,and imaging.However,a significant challenge is that once a metasurface is f...Nonlinear wavefront shaping is crucial for advancing optical technologies,enabling applications in optical computation,information processing,and imaging.However,a significant challenge is that once a metasurface is fabricated,the nonlinear wavefront it generates is fixed,offering little flexibility.This limitation often necessitates the fabrication of different metasurfaces for different wavefronts,which is both time-consuming and inefficient.To address this,we combine evolutionary algorithms with spatial light modulators(SLMs)to dynamically control wavefronts using a single metasurface,reducing the need for multiple fabrications and enabling the generation of arbitrary nonlinear wavefront patterns without requiring complicated optical alignment.We demonstrate this approach by introducing a genetic algorithm(GA)to manipulate visible wavefronts converted from near-infrared light via third-harmonic generation(THG)in a silicon metasurface.The Si metasurface supports multipolar Mie resonances that strongly enhance light-matter interactions,thereby significantly boosting THG emission at resonant positions.Additionally,the cubic relationship between THG emission and the infrared input reduces noise in the diffractive patterns produced by the SLM.This allows for precise experimental engineering of the nonlinear emission patterns with fewer alignment constraints.Our approach paves the way for self-optimized nonlinear wavefront shaping,advancing optical computation and information processing techniques.展开更多
Dielectric metasurfaces play an increasingly important role in enhancing optical nonlinear generations owing to their ability to support strong light-matter interactions based on Mie-type multipolar resonances.Compare...Dielectric metasurfaces play an increasingly important role in enhancing optical nonlinear generations owing to their ability to support strong light-matter interactions based on Mie-type multipolar resonances.Compared to metasurfaces composed of the periodic arrangement of nanoparticles,inverse,so-called,membrane metasurfaces offer unique possibilities for supporting multipolar resonances,while maintaining small unit cell size,large mode volume and high field enhancement for enhancing nonlinear frequency conversion.Here,we theoretically and experimentally investigate the formation of bound states in the continuum(BICs)from silicon dimer-hole membrane metasurfaces.We demonstrate that our BIC-formed resonance features a strong and tailorable electric near-field confinement inside the silicon membrane films.Furthermore,we show that by tuning the gap between the holes,one can open a leaky channel to transform these regular BICs into quasi-BICs,which can be excited directly under normal plane wave incidence.To prove the capabilities of such metasurfaces,we demonstrate the conversion of an infrared image to the visible range,based on the Third-harmonic generation(THG)process with the resonant membrane metasurfaces.Our results suggest a new paradigm for realising efficient nonlinear photonics metadevices and hold promise for extending the applications of nonlinear structuring surfaces to new types of all-optical near-infrared imaging technologies.展开更多
Miniaturized on-chip spectrometers with small footprints,lightweight,and low cost are in great demand for portable optical sensing,lab-on-chip systems,and so on.Such miniaturized spectrometers are usually based on eng...Miniaturized on-chip spectrometers with small footprints,lightweight,and low cost are in great demand for portable optical sensing,lab-on-chip systems,and so on.Such miniaturized spectrometers are usually based on engineered spectral response units and then reconstruct unknown spectra with algorithms.However,due to the limited footprints of computational on-chip spectrometers,the recovered spectral resolution is limited by the number of integrated spectral response units/filters.Thus,it is challenging to improve the spectral resolution without increasing the number of used filters.Here we present a computational on-chip spectrometer using electrochromic filter-based computational spectral units that can be electrochemically modulated to increase the efficient sampling number for higher spectral resolution.These filters are directly integrated on top of the photodetector pixels,and the spectral modulation of the filters results from redox reactions during the dual injection of ions and electrons into the electrochromic material.We experimentally demonstrate that the spectral resolution of the proposed spectrometer can be effectively improved as the number of applied voltages increases.The average difference of the peak wavelengths between the reconstructed and the reference spectra decreases from 1.61 nm to 0.29 nm.We also demonstrate the proposed spectrometer can be worked with only four or two filter units,assisted by electrochromic modulation.In addition,we also demonstrate that the electrochromic filter can be easily adapted for hyperspectral imaging,due to its uniform transparency.This strategy suggests a new way to enhance the performance of miniaturized spectrometers with tunable spectral filters for high resolution,low-cost,and portable spectral sensing,and would also inspire the exploration of other stimulus responses such as photochromic and force-chromic,etc,on computational spectrometers.展开更多
Nonlinear metasurfaces have experienced rapid growth recently due to their potential in various applications,including infrared imaging and spectroscopy.However,due to the low conversion efficiencies of metasurfaces,s...Nonlinear metasurfaces have experienced rapid growth recently due to their potential in various applications,including infrared imaging and spectroscopy.However,due to the low conversion efficiencies of metasurfaces,several strategies have been adopted to enhance their performances,including employing resonances at signal or nonlinear emission wavelengths.This strategy results in a narrow operational band of the nonlinear metasurfaces,which has bottlenecked many applications,including nonlinear holography,image encoding,and nonlinear metalenses.Here,we overcome this issue by introducing a new nonlinear imaging platform utilizing a pump beam to enhance signal conversion through four-wave mixing(FWM),whereby the metasurface is resonant at the pump wavelength rather than the signal or nonlinear emissions.As a result,we demonstrate broadband nonlinear imaging for arbitrary objects using metasurfaces.A silicon disk-on-slab metasurface is introduced with an excitable guided-mode resonance at the pump wavelength.This enabled direct conversion of a broad IR image ranging from>1000 to 4000 nm into visible.Importantly,adopting FWM substantially reduces the dependence on high-power signal inputs or resonant features at the signal beam of nonlinear imaging by utilizing the quadratic relationship between the pump beam intensity and the signal conversion efficiency.Our results,therefore,unlock the potential for broadband infrared imaging capabilities with metasurfaces,making a promising advancement for next-generation all-optical infrared imaging techniques with chip-scale photonic devices.展开更多
Circadian rhythms play crucial roles in orchestrating diverse physiological processes that are critical for health and disease.Dysregulated circadian rhythms are closely associated with various human metabolic disease...Circadian rhythms play crucial roles in orchestrating diverse physiological processes that are critical for health and disease.Dysregulated circadian rhythms are closely associated with various human metabolic diseases,including type 2 diabetes,cardiovascular disease,and non-alcoholic fatty liver disease.Modern lifestyles are frequently associated with an irregular circadian rhythm,which poses a significant risk to public health.While the central clock has a set periodicity,circadian oscillators in peripheral organs,particularly in the liver,can be entrained by metabolic alterations or stress cues.At the molecular level,the signal transduction pathways that mediate stress responses interact with the key determinants of circadian oscillation to maintain metabolic homeostasis under physiological or pathological conditions.In the liver,a number of nuclear receptors or transcriptional regulators,which are regulated by metabolites,hormones,the circadian clock,or environmental stressors,serve as direct links between stress responses and circadian metabolism.In this review,we summarize recent advances in the understanding of the interactions between stress responses(endoplasmic reticulum stress response,oxidative stress response,and inflammatory responses)and circadian metabolism,and the role of these interactions in the development of metabolic diseases.展开更多
Entity and relation extraction is an indispensable part of domain knowledge graph construction,which can serve relevant knowledge needs in a specific domain,such as providing support for product research,sales,risk co...Entity and relation extraction is an indispensable part of domain knowledge graph construction,which can serve relevant knowledge needs in a specific domain,such as providing support for product research,sales,risk control,and domain hotspot analysis.The existing entity and relation extraction methods that depend on pretrained models have shown promising performance on open datasets.However,the performance of these methods degrades when they face domain-specific datasets.Entity extraction models treat characters as basic semantic units while ignoring known character dependency in specific domains.Relation extraction is based on the hypothesis that the relations hidden in sentences are unified,thereby neglecting that relations may be diverse in different entity tuples.To address the problems above,this paper first introduced prior knowledge composed of domain dictionaries to enhance characters’dependence.Second,domain rules were built to eliminate noise in entity relations and promote potential entity relation extraction.Finally,experiments were designed to verify the effectiveness of our proposed methods.Experimental results on two domains,including laser industry and unmanned ship,showed the superiority of our methods.The F1 value on laser industry entity,unmanned ship entity,laser industry relation,and unmanned ship relation datasets is improved by+1%,+6%,+2%,and+1%,respectively.In addition,the extraction accuracy of entity relation triplet reaches 83%and 76%on laser industry entity pair and unmanned ship entity pair datasets,respectively.展开更多
基金support from the Biotechnology and Biological Council Doctoral Training Programme(BBSRC DTP)the support from the Royal Society and Wolfson Foundation(RSWF\FT\191022).
文摘Nonlinear wavefront shaping is crucial for advancing optical technologies,enabling applications in optical computation,information processing,and imaging.However,a significant challenge is that once a metasurface is fabricated,the nonlinear wavefront it generates is fixed,offering little flexibility.This limitation often necessitates the fabrication of different metasurfaces for different wavefronts,which is both time-consuming and inefficient.To address this,we combine evolutionary algorithms with spatial light modulators(SLMs)to dynamically control wavefronts using a single metasurface,reducing the need for multiple fabrications and enabling the generation of arbitrary nonlinear wavefront patterns without requiring complicated optical alignment.We demonstrate this approach by introducing a genetic algorithm(GA)to manipulate visible wavefronts converted from near-infrared light via third-harmonic generation(THG)in a silicon metasurface.The Si metasurface supports multipolar Mie resonances that strongly enhance light-matter interactions,thereby significantly boosting THG emission at resonant positions.Additionally,the cubic relationship between THG emission and the infrared input reduces noise in the diffractive patterns produced by the SLM.This allows for precise experimental engineering of the nonlinear emission patterns with fewer alignment constraints.Our approach paves the way for self-optimized nonlinear wavefront shaping,advancing optical computation and information processing techniques.
基金the support from the Royal Society scholarshipsupport from the UK Research and Innovation Future Leaders Fellowship (MR/T040513/1).
文摘Dielectric metasurfaces play an increasingly important role in enhancing optical nonlinear generations owing to their ability to support strong light-matter interactions based on Mie-type multipolar resonances.Compared to metasurfaces composed of the periodic arrangement of nanoparticles,inverse,so-called,membrane metasurfaces offer unique possibilities for supporting multipolar resonances,while maintaining small unit cell size,large mode volume and high field enhancement for enhancing nonlinear frequency conversion.Here,we theoretically and experimentally investigate the formation of bound states in the continuum(BICs)from silicon dimer-hole membrane metasurfaces.We demonstrate that our BIC-formed resonance features a strong and tailorable electric near-field confinement inside the silicon membrane films.Furthermore,we show that by tuning the gap between the holes,one can open a leaky channel to transform these regular BICs into quasi-BICs,which can be excited directly under normal plane wave incidence.To prove the capabilities of such metasurfaces,we demonstrate the conversion of an infrared image to the visible range,based on the Third-harmonic generation(THG)process with the resonant membrane metasurfaces.Our results suggest a new paradigm for realising efficient nonlinear photonics metadevices and hold promise for extending the applications of nonlinear structuring surfaces to new types of all-optical near-infrared imaging technologies.
基金supported by the National Natural Science Foundation of China(U23A20481,62075004,11804018,62275010)Beijing Municipal Natural Science Foundation(1232027)+2 种基金China Postdoctoral Science Foundation(2022M720347,2024T171115)the International Postdoctoral Exchange Fellowship Program(YJ20220241)the Fundamental Research Funds for the Central Universities.
文摘Miniaturized on-chip spectrometers with small footprints,lightweight,and low cost are in great demand for portable optical sensing,lab-on-chip systems,and so on.Such miniaturized spectrometers are usually based on engineered spectral response units and then reconstruct unknown spectra with algorithms.However,due to the limited footprints of computational on-chip spectrometers,the recovered spectral resolution is limited by the number of integrated spectral response units/filters.Thus,it is challenging to improve the spectral resolution without increasing the number of used filters.Here we present a computational on-chip spectrometer using electrochromic filter-based computational spectral units that can be electrochemically modulated to increase the efficient sampling number for higher spectral resolution.These filters are directly integrated on top of the photodetector pixels,and the spectral modulation of the filters results from redox reactions during the dual injection of ions and electrons into the electrochromic material.We experimentally demonstrate that the spectral resolution of the proposed spectrometer can be effectively improved as the number of applied voltages increases.The average difference of the peak wavelengths between the reconstructed and the reference spectra decreases from 1.61 nm to 0.29 nm.We also demonstrate the proposed spectrometer can be worked with only four or two filter units,assisted by electrochromic modulation.In addition,we also demonstrate that the electrochromic filter can be easily adapted for hyperspectral imaging,due to its uniform transparency.This strategy suggests a new way to enhance the performance of miniaturized spectrometers with tunable spectral filters for high resolution,low-cost,and portable spectral sensing,and would also inspire the exploration of other stimulus responses such as photochromic and force-chromic,etc,on computational spectrometers.
基金the Royal Society scholarshipG.S.acknowledges support from Biotechnology and Biological Council Doctoral Training Programme(BBSRC DTP)+1 种基金D.S.and D.N.N.acknowledge the support by the Australian Research Council(CE200100010 and FT230100058)L.Xu and M.Rahmani acknowledge support from the UK Research and Innovation Future Leaders Fellowship(MR/T040513/1)。
文摘Nonlinear metasurfaces have experienced rapid growth recently due to their potential in various applications,including infrared imaging and spectroscopy.However,due to the low conversion efficiencies of metasurfaces,several strategies have been adopted to enhance their performances,including employing resonances at signal or nonlinear emission wavelengths.This strategy results in a narrow operational band of the nonlinear metasurfaces,which has bottlenecked many applications,including nonlinear holography,image encoding,and nonlinear metalenses.Here,we overcome this issue by introducing a new nonlinear imaging platform utilizing a pump beam to enhance signal conversion through four-wave mixing(FWM),whereby the metasurface is resonant at the pump wavelength rather than the signal or nonlinear emissions.As a result,we demonstrate broadband nonlinear imaging for arbitrary objects using metasurfaces.A silicon disk-on-slab metasurface is introduced with an excitable guided-mode resonance at the pump wavelength.This enabled direct conversion of a broad IR image ranging from>1000 to 4000 nm into visible.Importantly,adopting FWM substantially reduces the dependence on high-power signal inputs or resonant features at the signal beam of nonlinear imaging by utilizing the quadratic relationship between the pump beam intensity and the signal conversion efficiency.Our results,therefore,unlock the potential for broadband infrared imaging capabilities with metasurfaces,making a promising advancement for next-generation all-optical infrared imaging techniques with chip-scale photonic devices.
基金This research was supported by USA National Institutes of Health(NIH)grants DK090313,ES017829,and AR066634(to K.Zhang)American Heart Association Grants 0635423Z and 09GRNT2280479(to K.Zhang).
文摘Circadian rhythms play crucial roles in orchestrating diverse physiological processes that are critical for health and disease.Dysregulated circadian rhythms are closely associated with various human metabolic diseases,including type 2 diabetes,cardiovascular disease,and non-alcoholic fatty liver disease.Modern lifestyles are frequently associated with an irregular circadian rhythm,which poses a significant risk to public health.While the central clock has a set periodicity,circadian oscillators in peripheral organs,particularly in the liver,can be entrained by metabolic alterations or stress cues.At the molecular level,the signal transduction pathways that mediate stress responses interact with the key determinants of circadian oscillation to maintain metabolic homeostasis under physiological or pathological conditions.In the liver,a number of nuclear receptors or transcriptional regulators,which are regulated by metabolites,hormones,the circadian clock,or environmental stressors,serve as direct links between stress responses and circadian metabolism.In this review,we summarize recent advances in the understanding of the interactions between stress responses(endoplasmic reticulum stress response,oxidative stress response,and inflammatory responses)and circadian metabolism,and the role of these interactions in the development of metabolic diseases.
基金This work is funded by the Shanghai Sailing Program(Grant No.20YF1413800)Military Medical Science and Technology Youth Cultivating Program(Grant No.20QNPY106)High Performance Computing Center of Shanghai University,and Shanghai Engineering Research Center of Intelligent Computing System(Grant No.19DZ2252600).
文摘Entity and relation extraction is an indispensable part of domain knowledge graph construction,which can serve relevant knowledge needs in a specific domain,such as providing support for product research,sales,risk control,and domain hotspot analysis.The existing entity and relation extraction methods that depend on pretrained models have shown promising performance on open datasets.However,the performance of these methods degrades when they face domain-specific datasets.Entity extraction models treat characters as basic semantic units while ignoring known character dependency in specific domains.Relation extraction is based on the hypothesis that the relations hidden in sentences are unified,thereby neglecting that relations may be diverse in different entity tuples.To address the problems above,this paper first introduced prior knowledge composed of domain dictionaries to enhance characters’dependence.Second,domain rules were built to eliminate noise in entity relations and promote potential entity relation extraction.Finally,experiments were designed to verify the effectiveness of our proposed methods.Experimental results on two domains,including laser industry and unmanned ship,showed the superiority of our methods.The F1 value on laser industry entity,unmanned ship entity,laser industry relation,and unmanned ship relation datasets is improved by+1%,+6%,+2%,and+1%,respectively.In addition,the extraction accuracy of entity relation triplet reaches 83%and 76%on laser industry entity pair and unmanned ship entity pair datasets,respectively.
