With the advent of the era of big data,artificial intelligence has attracted continuous attention from all walks of life,and has been widely used in medical image analysis,molecular and material science,language recog...With the advent of the era of big data,artificial intelligence has attracted continuous attention from all walks of life,and has been widely used in medical image analysis,molecular and material science,language recognition and other fields.As the basis of artificial intelligence,the research results of neural network are remarkable.However,due to the inherent defect that electrical signal is easily interfered and the processing speed is proportional to the energy loss,researchers have turned their attention to light,trying to build neural networks in the field of optics,making full use of the parallel processing ability of light to solve the problems of electronic neural networks.After continuous research and development,optical neural network has become the forefront of the world.Here,we mainly introduce the development of this field,summarize and compare some classical researches and algorithm theories,and look forward to the future of optical neural network.展开更多
In recent years,the explosive development of artificial intelligence implementing by artificial neural networks(ANNs)creates inconceivable demands for computing hardware.However,conventional computing hardware based o...In recent years,the explosive development of artificial intelligence implementing by artificial neural networks(ANNs)creates inconceivable demands for computing hardware.However,conventional computing hardware based on electronic transistor and von Neumann architecture cannot satisfy such an inconceivable demand due to the unsustainability of Moore’s Law and the failure of Dennard’s scaling rules.Fortunately,analog optical computing offers an alternative way to release unprecedented computational capability to accelerate varies computing drained tasks.In this article,the challenges of the modern computing technologies and potential solutions are briefly explained in Chapter 1.In Chapter 2,the latest research progresses of analog optical computing are separated into three directions:vector/matrix manipulation,reservoir computing and photonic Ising machine.Each direction has been explicitly summarized and discussed.The last chapter explains the prospects and the new challenges of analog optical computing.展开更多
Holography has attracted tremendous interest due to its capability of storing boththe amplitude and phase of light field and reproducing vivid three-dimensionalscenes. However, the large pixel size, low resolution, sm...Holography has attracted tremendous interest due to its capability of storing boththe amplitude and phase of light field and reproducing vivid three-dimensionalscenes. However, the large pixel size, low resolution, small field-of-view (FOV) andlimited space-bandwidth of traditional spatial light modulator (SLM) devices restrictthe possibility of improving the quality of reconstructed images. With thedevelopment of nanofabrication technologies, metasurfaces have shown greatpotential in manipulating the amplitude, phase, polarization, frequency orsimultaneously multiple parameters of output light in ultrashort distance withsubwavelength resolution by tailoring the scattering behaviour of consistednanostructures. Such flexibilities make metasurface a promising candidate forholographic related applications. Here, we review recent progresses in the field ofmetasurface holography. From the perspective of the fundamental properties oflight, we classify the metasurface holography into several categories such as phaseonlyholography, amplitude-only holography, complex amplitude holography and soon. Then, we introduce the corresponding working principles and design strategies.Meanwhile, some emerging types of metasurface holography such as tunableholography, nonlinear holography, Janus (or directional related) and bilayermetasurfaces holography are also discussed. At last, we make our outlook onmetasurface holography and discuss the challenges we may face in the future.展开更多
Applying intelligence algorithms to conceive nanoscale meta-devices becomes a flourishing and extremely active scientific topic over the past few years.Inverse design of functional nanostructures is at the heart of th...Applying intelligence algorithms to conceive nanoscale meta-devices becomes a flourishing and extremely active scientific topic over the past few years.Inverse design of functional nanostructures is at the heart of this topic,in which artificial intelligence(AI)furnishes various optimization toolboxes to speed up prototyping of photonic layouts with enhanced performance.In this review,we offer a systemic view on recent advancements in nanophotonic components designed by intelligence algorithms,manifesting a development trend from performance optimizations towards inverse creations of novel designs.To illustrate interplays between two fields,AI and photonics,we take meta-atom spectral manipulation as a case study to introduce algorithm operational principles,and subsequently review their manifold usages among a set of popular meta-elements.As arranged from levels of individual optimized piece to practical system,we discuss algorithm-assisted nanophotonic designs to examine their mutual benefits.We further comment on a set of open questions including reasonable applications of advanced algorithms,expensive data issue,and algorithm benchmarking,etc.Overall,we envision mounting photonic-targeted methodologies to substantially push forward functional artificial meta-devices to profit both fields.展开更多
Computational microscopy,as a subfield of computational imaging,combines optical manipulation and image algorithmic reconstruction to recover multi-dimensional microscopic images or information of micro-objects.In rec...Computational microscopy,as a subfield of computational imaging,combines optical manipulation and image algorithmic reconstruction to recover multi-dimensional microscopic images or information of micro-objects.In recent years,the revolution in light-emitting diodes(LEDs),low-cost consumer image sensors,modern digital computers,and smartphones provide fertile opportunities for the rapid development of computational microscopy.Consequently,diverse forms of computational microscopy have been invented,including digital holographic microscopy(DHM),transport of intensity equation(TIE),differential phase contrast(DPC)microscopy,lens-free on-chip holography,and Fourier ptychographic microscopy(FPM).These computational microscopy techniques not only provide high-resolution,label-free,quantitative phase imaging capability but also decipher new and advanced biomedical research and industrial applications.Nevertheless,most computational microscopy techniques are still at an early stage of“proof of concept”or“proof of prototype”(based on commercially available microscope platforms).Translating those concepts to stand-alone optical instruments for practical use is an essential step for the promotion and adoption of computational microscopy by the wider bio-medicine,industry,and education community.In this paper,we present four smart computational light microscopes(SCLMs)developed by our laboratory,i.e.,smart computational imaging laboratory(SCILab)of Nanjing University of Science and Technology(NJUST),China.These microscopes are empowered by advanced computational microscopy techniques,including digital holography,TIE,DPC,lensless holography,and FPM,which not only enables multi-modal contrast-enhanced observations for unstained specimens,but also can recover their three-dimensional profiles quantitatively.We introduce their basic principles,hardware configurations,reconstruction algorithms,and software design,quantify their imaging performance,and illustrate their typical applications for cell analysis,medical diagnosis,and microlens characterization.展开更多
The orbital angular momentum (OAM) of beams provides a new dimension, andhave already found lots of applications in various domains. Among suchapplications, the precisely and quantitatively diagnostic of intensity dis...The orbital angular momentum (OAM) of beams provides a new dimension, andhave already found lots of applications in various domains. Among suchapplications, the precisely and quantitatively diagnostic of intensity distributionsamong different OAM modes, namely the OAM spectrum of a beam, is of greatsignificance. In this paper we propose and experimentally validate a simpleinterferential method to achieve this goal. By analyzing the interference patternformed by the beam and a reference field, the OAM spectrum can be obtainedinstantaneously. Furthermore, the proposed method is also available for morecomplex light fields, for instance, the multi-ring optical vortices. In the proof-ofconceptexperiment, the OAM spectra of both single-mode and N-foldmultiplexed OAM modes with various intensity distributions are well detected.Our work offers a new way to precisely measure the OAM spectra of beams andwill advance the development of many applications ranging from classical toquantum physics as the OAM based large-capacity data transmissions, rotationdetection, quantum manipulation and so on.展开更多
With the non-ionizing,non-invasive,high penetration,high resolution and spectral fingerprinting features of terahertz(THz)wave,THz spectroscopy has great potential for the qualitative and quantitative identification o...With the non-ionizing,non-invasive,high penetration,high resolution and spectral fingerprinting features of terahertz(THz)wave,THz spectroscopy has great potential for the qualitative and quantitative identification of key substances in biomedical field,such as the early diagnosis of cancer,the accurate boundary determination of pathological tissue and non-destructive detection of superficial tissue.However,biological samples usually contain various of substances(such as water,proteins,fat and fiber),resulting in the signal-to-noise ratio(SNR)for the absorption peaks of target substances are very small and then the target substances are hard to be identified.Here,we present recent works for the SNR improvement of THz signal.These works include the usage of attenuated total reflection(ATR)spectroscopy,the fabrication of sample-sensitive metamaterials,the utilization of different agents(including contrast agents,optical clearing agents and aptamers),the application of reconstruction algorithms and the optimization of THz spectroscopy system.These methods have been proven to be effective theoretically,but only few of them have been applied into actual usage.We also analyze the reasons and summarize the advantages and disadvantages of each method.At last,we present the prospective application of THz spectroscopy in biomedical field.展开更多
Femtosecond laser machining of biomimetic micro/nanostructures with high aspect ratio(larger than 10)on ultrahard materials,such as sapphire,is a challenging task,because the uncontrollable surface damage usually resu...Femtosecond laser machining of biomimetic micro/nanostructures with high aspect ratio(larger than 10)on ultrahard materials,such as sapphire,is a challenging task,because the uncontrollable surface damage usually results in poor surface structures,especially for deep scribing.Here,we report an inside-out femtosecond laser deep scribing technology in combination with etching process for fabricating bio-inspired micro/nanostructures with high-aspect-ratio on sapphire.To effectively avoid the uncontrollable damage at the solid/air interface,a sacrificial layer of silicon oxide was employed for surface protection.High-quality microstructures with an aspect ratio as high as 80:1 have been fabricated on sapphire surface.As a proof-of-concept application,we produced a moth-eye inspired antireflective window with sub-wavelength pyramid arrays on sapphire surface,by which broadband(3-5μm)and high transmittance(98%at 4μm,the best results reported so far)have been achieved.The sacrificial layer assisted inside-out femtosecond laser deep scribing technology is effective and universal,holding great promise for producing micro/nanostructured optical devices.展开更多
In this paper, we propose a holographic capture and projection system of real objectsbased on tunable zoom lenses. Different from the traditional holographic system, aliquid lens-based zoom camera and a digital conica...In this paper, we propose a holographic capture and projection system of real objectsbased on tunable zoom lenses. Different from the traditional holographic system, aliquid lens-based zoom camera and a digital conical lens are used as key parts to reachthe functions of holographic capture and projection, respectively. The zoom camera isproduced by combing liquid lenses and solid lenses, which has the advantages of fastresponse and light weight. By electrically controlling the curvature of the liquid-liquidsurface, the focal length of the zoom camera can be changed easily. As anothertunable zoom lens, the digital conical lens has a large focal depth and the opticalproperty is perfectly used in the holographic system for adaptive projection, especiallyfor multilayer imaging. By loading the phase of the conical lens on the spatial lightmodulator, the reconstructed image can be projected with large depths. With theproposed system, holographic zoom capture and color reproduction of real objects canbe achieved based on a simple structure. Experimental results verify the feasibility ofthe proposed system. The proposed system is expected to be applied to microprojectionand three-dimensional display technology.展开更多
In recent years,machine learning,especially various deep neural networks,as an emerging technique for data analysis and processing,has brought novel insights into the development of fiber lasers,in particular complex,...In recent years,machine learning,especially various deep neural networks,as an emerging technique for data analysis and processing,has brought novel insights into the development of fiber lasers,in particular complex,dynamical,or disturbance-sensitive fiber laser systems.This paper highlights recent attractive research that adopted machine learning in the fiber laser field,including design and manipulation for ondemand laser output,prediction and control of nonlinear effects,reconstruction and evaluation of laser properties,as well as robust control for lasers and laser systems.We also comment on the challenges and potential future development.展开更多
High-speed optical interconnects of data centers and high performance computers(HPC) have become the rapid development direction in the field of opticalcommunication owing to the explosive growth of market demand. Cur...High-speed optical interconnects of data centers and high performance computers(HPC) have become the rapid development direction in the field of opticalcommunication owing to the explosive growth of market demand. Currently, opticalinterconnect systems are moving towards higher capacity and integration.High-sensitivity receivers with avalanche photodiodes (APDs) are paid more attentiondue to the capability to enhance gain bandwidth. The impact ionization coefficientratio is one crucial parameter for avalanche photodiode optimization, whichsignificantly affects the excess noise and the gain bandwidth product (GBP). Thedevelopment of silicon-germanium (Si-Ge) APDs are promising thanks to the lowimpact ionization coefficient ratio of silicon, the simple structure, and the CMOScompatible process. Separate absorption charge multiplication (SACM) structures aretypically adopted in Si-Ge APDs to achieve high bandwidth and low noise. This paperreviews design and optimization in high-speed Si-Ge APDs, including advanced APDstructures, APD modeling and APD receivers.展开更多
Orbital angular momentum(OAM)detection underpins almost all aspects of vortex beams’advances such as communication and quantum analogy.Conventional schemes are frustrated by low speed,complicated system,limited detec...Orbital angular momentum(OAM)detection underpins almost all aspects of vortex beams’advances such as communication and quantum analogy.Conventional schemes are frustrated by low speed,complicated system,limited detection range.Here,we devise an intelligent processor composed of photonic and electronic neurons for OAM spectrum measurement in a fast,accurate and direct manner.Specifically,optical layers extract invisible topological charge information from incoming light and a shallow electronic layer predicts the exact spectrum.The integration of optical-computing promises us a compact single-shot system with high speed and energy efficiency(optical operations/electronic operations~10^(3)),neither necessitating reference wave nor repetitive steps.Importantly,our processor is endowed with salient generalization ability and robustness against diverse structured light and adverse effects(mean squared error~10^((−5))).We further raise a universal model interpretation paradigm to reveal the underlying physical mechanisms in the hybrid processor,as distinct from conventional‘black-box’networks.Such interpretation algorithm can improve the detection efficiency up to 25-fold.We also complete the theory of optoelectronic network enabling its efficient training.This work not only contributes to the explorations on OAM physics and applications,and also broadly inspires the advanced links between intelligent computing and physical effects.展开更多
Electromagnetic anapole mode is a nonradiative state of light originating from the deconstructive interference of radiation of the oscillating electric and toroidal dipole moments.The high quality anapole-related reso...Electromagnetic anapole mode is a nonradiative state of light originating from the deconstructive interference of radiation of the oscillating electric and toroidal dipole moments.The high quality anapole-related resonances can be used in enhancing nonlinear electromagnetic properties of materials and in sensor applications.In this work,we experimentally demonstrate plasmonic anapole metamaterial sensor of environmental refractive index in the optical part of the spectrum.Our results show that the sensor exhibits high sensitivity to the ambient refractive index at the level of 330 nm/RIU and noise floor of 8.7×10^(-5)RIU.This work will pave the way for applications of anapole metamaterials in biosensing and spectroscopy.展开更多
Terahertz technology has broad application prospects in biomedical detection.However, the mixed characteristics of actual samples make the terahertz spectrumcomplex and difficult to distinguish, and there is no practi...Terahertz technology has broad application prospects in biomedical detection.However, the mixed characteristics of actual samples make the terahertz spectrumcomplex and difficult to distinguish, and there is no practical terahertz detectionmethod for clinical medicine. Here, we propose a three-step one-way terahertzmodel, presenting a detailed flow analysis of terahertz technology in the biomedicaldetection of renal fibrosis as an example: 1) biomarker determination: screeningdisease biomarkers and establishing the terahertz spectrum and concentrationgradient;2) mixture interference removal: clearing the interfering signals in the mixturefor the biomarker in the animal model and evaluating and retaining the effectivecharacteristic peaks;and 3) individual difference removal: excluding individualinterference differences and confirming the final effective terahertz parameters in thehuman sample. The root mean square error of our model is three orders ofmagnitude lower than that of the gold standard, with profound implications for therapid, accurate and early detection of diseases.展开更多
Over the past 5 years,digital coding and programmable metamaterials have beendeveloped rapidly since their first exhibition in 2014.The iconic feature of the digitalcoding metamaterial is using digital codes like"...Over the past 5 years,digital coding and programmable metamaterials have beendeveloped rapidly since their first exhibition in 2014.The iconic feature of the digitalcoding metamaterial is using digital codes like"0"and"1 to represent the distinctelectromagnetic(EM)responses.This seemingly trivial progress has successfullyreform the design theory from the effective medium to coding patterns,bridgingthe physical world and digital information world.More interestingly,beyond thesimple coding on the parameters or patterns,the digital coding metamaterials aremore intend to introduce the concept of direct interactions and operations of digitalinformation within EM fields,to realize infomation processing,transmission orrecognition.Toaccurately exhibit the informational specialties,we classify the codingmetamaterials,digital metamaterials and programmable metamaterials,as well asother information-operating metamaterials,as information metamaterials In thisreview article,we fistly introduce the digital coding concept,working mechanism,and related design methods.Then,three important theories including the scatteringpattem calculation,convolution operationand entropyofdigital codingmetamaterials,arediscussed in details.Finally we introduce several system-level works based on theinfomation metamaterials,such as the new-architecture wireless communication systemsand reprogrammable imaging systems,to show the powerful manipulation capabilities ofinformation metamaterials.As the nextgeneration of infomation metamaterials,two proofof-concept smart metamaterials and their advanced architectures are discussed.In thesummary,the development track of information metamaterials and future trends are presented.展开更多
Accurate depiction of waves in temporal and spatial is essential to the investigation of interactions between physical objects and waves.Digital holography(DH)can perform quantitative analysis of wave-matter interacti...Accurate depiction of waves in temporal and spatial is essential to the investigation of interactions between physical objects and waves.Digital holography(DH)can perform quantitative analysis of wave-matter interactions.Full detector-bandwidth reconstruc-tion can be realized based on in-line DH.But the overlapping of twin images strongly prevents quantitative analysis.For off-axis DH,the object wave and the detector bandwidth need to satisfy certain conditions to perform reconstruction accurately.Here,we present a reliable approach involving a coupled configuration for combining two in-line holograms and one off-axis hologram,using a rapidly converging iterative procedure based on two-plane coupled phase retrieval(TwPCPR)method.It realizes a fast-convergence holographic calculation method.High-resolution and full-field recon-struction by exploiting the full bandwidth are demonstrated for complex-amplitude reconstruction.Off-axis optimization phase provides an effective initial guess to avoid stagnation and minimize the required measurements of multi-plane phase retrieval.The proposed strategy works well for more extended samples without any prior assumptions of the objects including support,non-negative,sparse constraints,etc.It helps to enhance and empower applications in wavefront sensing,computational microscopy and biological tissue analysis.展开更多
Fourier transform, mapping the information in one domain to its reciprocal space, isof fundamental significance in real-time and parallel processing of massive data forsound and image manipulation. As a powerful platf...Fourier transform, mapping the information in one domain to its reciprocal space, isof fundamental significance in real-time and parallel processing of massive data forsound and image manipulation. As a powerful platform of high-efficiency wavecontrol, Huygens’ metasurface may offer to bridge the electromagnetic signalprocessing and analog Fourier transform at the hardware level and with remarkablyimproved performance. We here demonstrate a Huygens’ metasurface hologram,where the image pattern can be self-rotated or projected in free space bymodulating the phase distribution based on the rotational invariance, time-shiftingand scaling properties of Fourier transform. Our proof-of-concept experiment showshigh-efficiency imaging operation in accordance with theoretical predictions,validating the proposed scheme as an ideal way to perform largely parallel spatialdomainmathematical operations in the analog domain using electromagnetic fields.展开更多
Neuromorphic computing applies concepts extracted from neuroscience to developdevices shaped like neural systems and achieve brain-like capacity and efficiency. Inthis way, neuromorphic machines, able to learn from th...Neuromorphic computing applies concepts extracted from neuroscience to developdevices shaped like neural systems and achieve brain-like capacity and efficiency. Inthis way, neuromorphic machines, able to learn from the surrounding environmentto deduce abstract concepts and to make decisions, promise to start a technologicalrevolution transforming our society and our life. Current electronic implementationsof neuromorphic architectures are still far from competing with their biologicalcounterparts in terms of real-time information-processing capabilities, packingdensity and energy efficiency. A solution to this impasse is represented by theapplication of photonic principles to the neuromorphic domain creating in this waythe field of neuromorphic photonics. This new field combines the advantages ofphotonics and neuromorphic architectures to build systems with high efficiency,high interconnectivity and high information density, and paves the way to ultrafast,power efficient and low cost and complex signal processing. In this Perspective, wereview the rapid development of the neuromorphic computing field both in theelectronic and in the photonic domain focusing on the role and the applications ofmemristors. We discuss the need and the possibility to conceive a photonicmemristor and we offer a positive outlook on the challenges and opportunities forthe ambitious goal of realising the next generation of full-optical neuromorphichardware.展开更多
Protein assays show great importance in medical research and disease diagnoses.Liquid crystals(LCs),as a branch of sensitive materials,offer promising applicability in the field of biosensing.Herein,we developed an ul...Protein assays show great importance in medical research and disease diagnoses.Liquid crystals(LCs),as a branch of sensitive materials,offer promising applicability in the field of biosensing.Herein,we developed an ultrasensitive biosensor for the detection of low-concentration protein molecules,employing LC-amplified optofluidic resonators.In this design,the orientation of LCs was disturbed by immobilized protein molecules through the reduction of the vertical anchoring force from the alignment layer.A biosensing platform based on the whispering-gallery mode(WGM)from the LC-amplified optofluidic resonator was developed and explored,in which the spectral wavelength shift was monitored as the sensing parameter.The microbubble structure provided a stable and reliable WGM resonator with a high Q factor for LCs.It is demonstrated that the wall thickness of the microbubble played a key role in enhancing the sensitivity of the LC-amplified WGM microcavity.It is also found that protein molecules coated on the internal surface of microbubble led to their interactions with laser beams and the orientation transition of LCs.Both effects amplified the target information and triggered a sensitive wavelength shift in WGM spectra.A detection limit of 1 fM for bovine serum albumin(BSA)was achieved to demonstrate the high-sensitivity of our sensing platform in protein assays.Compared to the detection using a conventional polarized optical microscope(POM),the sensitivity was improved by seven orders of magnitude.Furthermore,multiple types of proteins and specific biosensing were also investigated to verify the potential of LC-amplified optofluidic resonators in the biomolecular detection.Our studies indicate that LC-amplified optofluidic resonators offer a new solution for the ultrasensitive real-time biosensing and the characterization of biomolecular interactions.展开更多
Nanoimprint lithography(NIL)has attracted attention recently as a promising fabrication method for dielectric metalenses owing to its low cost and high throughput,however,high aspect ratio(HAR)nanostructures are requi...Nanoimprint lithography(NIL)has attracted attention recently as a promising fabrication method for dielectric metalenses owing to its low cost and high throughput,however,high aspect ratio(HAR)nanostructures are required to manipulate the full 2πphase of light.Conventional NIL using a hard-polydimethylsiloxane(h-PDMS)mold inevitably incurs shear stress on the nanostructures which is inversely proportional to the surface area parallel to the direction of detachment.Therefore,HAR structures are subjected to larger shear stresses,causing structural failure.Herein,we propose a novel wet etching NIL method with no detachment process to fabricate flawless HAR metalenses.The water-soluble replica mold is fabricated with polyvinyl alcohol(PVA)which is simpler than an h-PDMS mold,and the flexibility of the PVA mold is suitable for direct printing as its high tensile modulus allows high-resolution patterning of HAR metalenses.The diffraction-limited focusing of the printed metalenses demonstrates that it operates as an ideal lens in the visible regime.This method can potentially be used for manufacturing various nanophotonic devices that require HAR nanostructures at low cost and high throughput,facilitating commercialization.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant 11773018 and Grant 61727802in part by the Key Research and Development programs in Jiangsu China under Grant BE2018126+1 种基金in part by the Fundamental Research Funds for the Central Universities under Grant 30919011401 and Grant 30920010001in part by the Leading Technology of Jiangsu Basic Research Plan under Grant BK20192003.
文摘With the advent of the era of big data,artificial intelligence has attracted continuous attention from all walks of life,and has been widely used in medical image analysis,molecular and material science,language recognition and other fields.As the basis of artificial intelligence,the research results of neural network are remarkable.However,due to the inherent defect that electrical signal is easily interfered and the processing speed is proportional to the energy loss,researchers have turned their attention to light,trying to build neural networks in the field of optics,making full use of the parallel processing ability of light to solve the problems of electronic neural networks.After continuous research and development,optical neural network has become the forefront of the world.Here,we mainly introduce the development of this field,summarize and compare some classical researches and algorithm theories,and look forward to the future of optical neural network.
文摘In recent years,the explosive development of artificial intelligence implementing by artificial neural networks(ANNs)creates inconceivable demands for computing hardware.However,conventional computing hardware based on electronic transistor and von Neumann architecture cannot satisfy such an inconceivable demand due to the unsustainability of Moore’s Law and the failure of Dennard’s scaling rules.Fortunately,analog optical computing offers an alternative way to release unprecedented computational capability to accelerate varies computing drained tasks.In this article,the challenges of the modern computing technologies and potential solutions are briefly explained in Chapter 1.In Chapter 2,the latest research progresses of analog optical computing are separated into three directions:vector/matrix manipulation,reservoir computing and photonic Ising machine.Each direction has been explicitly summarized and discussed.The last chapter explains the prospects and the new challenges of analog optical computing.
基金National Key Research and Development Program of China 2017YFB1002900,Ministry of Science and Technology,ChinaFok Ying-Tong Education Foundation of China(161009)+3 种基金Beijing Nova Program(Z171100001117047)Natural Science Foundation of Beijing Municipality(4172057)National Natural Science Foundation of China(61775019)Beijing Outstanding Young Scientist Program(BJJWZYJH01201910007022).
文摘Holography has attracted tremendous interest due to its capability of storing boththe amplitude and phase of light field and reproducing vivid three-dimensionalscenes. However, the large pixel size, low resolution, small field-of-view (FOV) andlimited space-bandwidth of traditional spatial light modulator (SLM) devices restrictthe possibility of improving the quality of reconstructed images. With thedevelopment of nanofabrication technologies, metasurfaces have shown greatpotential in manipulating the amplitude, phase, polarization, frequency orsimultaneously multiple parameters of output light in ultrashort distance withsubwavelength resolution by tailoring the scattering behaviour of consistednanostructures. Such flexibilities make metasurface a promising candidate forholographic related applications. Here, we review recent progresses in the field ofmetasurface holography. From the perspective of the fundamental properties oflight, we classify the metasurface holography into several categories such as phaseonlyholography, amplitude-only holography, complex amplitude holography and soon. Then, we introduce the corresponding working principles and design strategies.Meanwhile, some emerging types of metasurface holography such as tunableholography, nonlinear holography, Janus (or directional related) and bilayermetasurfaces holography are also discussed. At last, we make our outlook onmetasurface holography and discuss the challenges we may face in the future.
基金National Natural Science Foundation of China(No.62005224,61927820)National Key Research and Development Program of China(2017YFA0205700)。
文摘Applying intelligence algorithms to conceive nanoscale meta-devices becomes a flourishing and extremely active scientific topic over the past few years.Inverse design of functional nanostructures is at the heart of this topic,in which artificial intelligence(AI)furnishes various optimization toolboxes to speed up prototyping of photonic layouts with enhanced performance.In this review,we offer a systemic view on recent advancements in nanophotonic components designed by intelligence algorithms,manifesting a development trend from performance optimizations towards inverse creations of novel designs.To illustrate interplays between two fields,AI and photonics,we take meta-atom spectral manipulation as a case study to introduce algorithm operational principles,and subsequently review their manifold usages among a set of popular meta-elements.As arranged from levels of individual optimized piece to practical system,we discuss algorithm-assisted nanophotonic designs to examine their mutual benefits.We further comment on a set of open questions including reasonable applications of advanced algorithms,expensive data issue,and algorithm benchmarking,etc.Overall,we envision mounting photonic-targeted methodologies to substantially push forward functional artificial meta-devices to profit both fields.
基金supported by the National Natural Science Foundation of China(61905115)Leading Technology of Jiangsu Basic Research Plan(BK20192003)+3 种基金National Defense Science and Technology Foundation of China(2019-JCJQ-JJ-381)Youth Foundation of Jiangsu Province(BK20190445)Fundamental Research Funds for the Central Universities(30920032101)Open Research Fund of Jiangsu Key Laboratory of Spectral Imaging&Intelligent Sense(3091801410411).
文摘Computational microscopy,as a subfield of computational imaging,combines optical manipulation and image algorithmic reconstruction to recover multi-dimensional microscopic images or information of micro-objects.In recent years,the revolution in light-emitting diodes(LEDs),low-cost consumer image sensors,modern digital computers,and smartphones provide fertile opportunities for the rapid development of computational microscopy.Consequently,diverse forms of computational microscopy have been invented,including digital holographic microscopy(DHM),transport of intensity equation(TIE),differential phase contrast(DPC)microscopy,lens-free on-chip holography,and Fourier ptychographic microscopy(FPM).These computational microscopy techniques not only provide high-resolution,label-free,quantitative phase imaging capability but also decipher new and advanced biomedical research and industrial applications.Nevertheless,most computational microscopy techniques are still at an early stage of“proof of concept”or“proof of prototype”(based on commercially available microscope platforms).Translating those concepts to stand-alone optical instruments for practical use is an essential step for the promotion and adoption of computational microscopy by the wider bio-medicine,industry,and education community.In this paper,we present four smart computational light microscopes(SCLMs)developed by our laboratory,i.e.,smart computational imaging laboratory(SCILab)of Nanjing University of Science and Technology(NJUST),China.These microscopes are empowered by advanced computational microscopy techniques,including digital holography,TIE,DPC,lensless holography,and FPM,which not only enables multi-modal contrast-enhanced observations for unstained specimens,but also can recover their three-dimensional profiles quantitatively.We introduce their basic principles,hardware configurations,reconstruction algorithms,and software design,quantify their imaging performance,and illustrate their typical applications for cell analysis,medical diagnosis,and microlens characterization.
基金National Natural Science Foundation of China(NSFC)(11834001,61905012)National Postdoctoral Program for Innovative Talents of China(BX20190036)+2 种基金China Postdoctoral Science Foundation(2019M650015)Beijing Institute of Technology Research Fund Program for Young ScholarsCETC joint research foundation(6141B08231125).
文摘The orbital angular momentum (OAM) of beams provides a new dimension, andhave already found lots of applications in various domains. Among suchapplications, the precisely and quantitatively diagnostic of intensity distributionsamong different OAM modes, namely the OAM spectrum of a beam, is of greatsignificance. In this paper we propose and experimentally validate a simpleinterferential method to achieve this goal. By analyzing the interference patternformed by the beam and a reference field, the OAM spectrum can be obtainedinstantaneously. Furthermore, the proposed method is also available for morecomplex light fields, for instance, the multi-ring optical vortices. In the proof-ofconceptexperiment, the OAM spectra of both single-mode and N-foldmultiplexed OAM modes with various intensity distributions are well detected.Our work offers a new way to precisely measure the OAM spectra of beams andwill advance the development of many applications ranging from classical toquantum physics as the OAM based large-capacity data transmissions, rotationdetection, quantum manipulation and so on.
基金National Major Project of Scientific Instrument and Equipment Development(2017YFF0106300)National Natural Science Foundation of China(61922059,61771314,61722111,81961138014)+3 种基金Shanghai Rising-Star Program(17QA1402500)the 111 Project(D18014)the International Joint Lab Program supported by Science and Technology Commission Shanghai Municipality(17590750300)the Key project supported by Science and Technology Commission Shanghai Municipality(YDZX20193100004960).
文摘With the non-ionizing,non-invasive,high penetration,high resolution and spectral fingerprinting features of terahertz(THz)wave,THz spectroscopy has great potential for the qualitative and quantitative identification of key substances in biomedical field,such as the early diagnosis of cancer,the accurate boundary determination of pathological tissue and non-destructive detection of superficial tissue.However,biological samples usually contain various of substances(such as water,proteins,fat and fiber),resulting in the signal-to-noise ratio(SNR)for the absorption peaks of target substances are very small and then the target substances are hard to be identified.Here,we present recent works for the SNR improvement of THz signal.These works include the usage of attenuated total reflection(ATR)spectroscopy,the fabrication of sample-sensitive metamaterials,the utilization of different agents(including contrast agents,optical clearing agents and aptamers),the application of reconstruction algorithms and the optimization of THz spectroscopy system.These methods have been proven to be effective theoretically,but only few of them have been applied into actual usage.We also analyze the reasons and summarize the advantages and disadvantages of each method.At last,we present the prospective application of THz spectroscopy in biomedical field.
基金supported by the National Natural Science Foundation of China(NSFC,Grant Nos.61825502,61960206003,61935008 and 62105117)the Scientific Research Project of the Education Department of Jilin Province(JJKH20221005KJ).
文摘Femtosecond laser machining of biomimetic micro/nanostructures with high aspect ratio(larger than 10)on ultrahard materials,such as sapphire,is a challenging task,because the uncontrollable surface damage usually results in poor surface structures,especially for deep scribing.Here,we report an inside-out femtosecond laser deep scribing technology in combination with etching process for fabricating bio-inspired micro/nanostructures with high-aspect-ratio on sapphire.To effectively avoid the uncontrollable damage at the solid/air interface,a sacrificial layer of silicon oxide was employed for surface protection.High-quality microstructures with an aspect ratio as high as 80:1 have been fabricated on sapphire surface.As a proof-of-concept application,we produced a moth-eye inspired antireflective window with sub-wavelength pyramid arrays on sapphire surface,by which broadband(3-5μm)and high transmittance(98%at 4μm,the best results reported so far)have been achieved.The sacrificial layer assisted inside-out femtosecond laser deep scribing technology is effective and universal,holding great promise for producing micro/nanostructured optical devices.
基金supported by the National Natural Science Foundation of China under Grant No.61805130,61805169 and 61535007.
文摘In this paper, we propose a holographic capture and projection system of real objectsbased on tunable zoom lenses. Different from the traditional holographic system, aliquid lens-based zoom camera and a digital conical lens are used as key parts to reachthe functions of holographic capture and projection, respectively. The zoom camera isproduced by combing liquid lenses and solid lenses, which has the advantages of fastresponse and light weight. By electrically controlling the curvature of the liquid-liquidsurface, the focal length of the zoom camera can be changed easily. As anothertunable zoom lens, the digital conical lens has a large focal depth and the opticalproperty is perfectly used in the holographic system for adaptive projection, especiallyfor multilayer imaging. By loading the phase of the conical lens on the spatial lightmodulator, the reconstructed image can be projected with large depths. With theproposed system, holographic zoom capture and color reproduction of real objects canbe achieved based on a simple structure. Experimental results verify the feasibility ofthe proposed system. The proposed system is expected to be applied to microprojectionand three-dimensional display technology.
基金Natural Science Foundation of Hunan province,China(Grant No.2019JJ10005)supported by Projects for National Excellent Young Talents and Hunan Provincial Innovation Construct Project(No.2019RS3017).
文摘In recent years,machine learning,especially various deep neural networks,as an emerging technique for data analysis and processing,has brought novel insights into the development of fiber lasers,in particular complex,dynamical,or disturbance-sensitive fiber laser systems.This paper highlights recent attractive research that adopted machine learning in the fiber laser field,including design and manipulation for ondemand laser output,prediction and control of nonlinear effects,reconstruction and evaluation of laser properties,as well as robust control for lasers and laser systems.We also comment on the challenges and potential future development.
基金supported by Shaanxi Province Overseas High-Level Talents Program,Chinese Academy of Sciences 100 Talents Program,Xi’an Institute of Optics and Precision Mechanics Start-Up Funding,and State Key Laboratory of Transient Optics and Photonics Independent Research Project.
文摘High-speed optical interconnects of data centers and high performance computers(HPC) have become the rapid development direction in the field of opticalcommunication owing to the explosive growth of market demand. Currently, opticalinterconnect systems are moving towards higher capacity and integration.High-sensitivity receivers with avalanche photodiodes (APDs) are paid more attentiondue to the capability to enhance gain bandwidth. The impact ionization coefficientratio is one crucial parameter for avalanche photodiode optimization, whichsignificantly affects the excess noise and the gain bandwidth product (GBP). Thedevelopment of silicon-germanium (Si-Ge) APDs are promising thanks to the lowimpact ionization coefficient ratio of silicon, the simple structure, and the CMOScompatible process. Separate absorption charge multiplication (SACM) structures aretypically adopted in Si-Ge APDs to achieve high bandwidth and low noise. This paperreviews design and optimization in high-speed Si-Ge APDs, including advanced APDstructures, APD modeling and APD receivers.
基金National Natural Science Foundation of China(61975087)Natural Science Foundation of China(62275137).
文摘Orbital angular momentum(OAM)detection underpins almost all aspects of vortex beams’advances such as communication and quantum analogy.Conventional schemes are frustrated by low speed,complicated system,limited detection range.Here,we devise an intelligent processor composed of photonic and electronic neurons for OAM spectrum measurement in a fast,accurate and direct manner.Specifically,optical layers extract invisible topological charge information from incoming light and a shallow electronic layer predicts the exact spectrum.The integration of optical-computing promises us a compact single-shot system with high speed and energy efficiency(optical operations/electronic operations~10^(3)),neither necessitating reference wave nor repetitive steps.Importantly,our processor is endowed with salient generalization ability and robustness against diverse structured light and adverse effects(mean squared error~10^((−5))).We further raise a universal model interpretation paradigm to reveal the underlying physical mechanisms in the hybrid processor,as distinct from conventional‘black-box’networks.Such interpretation algorithm can improve the detection efficiency up to 25-fold.We also complete the theory of optoelectronic network enabling its efficient training.This work not only contributes to the explorations on OAM physics and applications,and also broadly inspires the advanced links between intelligent computing and physical effects.
基金supported by the UK Engineering and Physical Science Research Council(grants EP/M009122/1 and EP/T02643X/1)the Royal Society(grant IEC/R3/170092)+6 种基金the European Research Council(Advanced Grant No.FLEET-786851)the Singapore Ministry of Education(N.I.Z.grant MOE2016-T3-1-006)the University Grants Committee/Research Grants Council of the Hong Kong Special Administrative Region,China(Project No.AoE/P-502/20 and GRF Project:15303521)the Shenzhen Science and Technology Innovation Commission(Grant No.SGDX2019081623281169)the Department of Science and Technology of Guangdong Province(2020B1515120073)the City University of Hong Kong(Grant No.9380131).
文摘Electromagnetic anapole mode is a nonradiative state of light originating from the deconstructive interference of radiation of the oscillating electric and toroidal dipole moments.The high quality anapole-related resonances can be used in enhancing nonlinear electromagnetic properties of materials and in sensor applications.In this work,we experimentally demonstrate plasmonic anapole metamaterial sensor of environmental refractive index in the optical part of the spectrum.Our results show that the sensor exhibits high sensitivity to the ambient refractive index at the level of 330 nm/RIU and noise floor of 8.7×10^(-5)RIU.This work will pave the way for applications of anapole metamaterials in biosensing and spectroscopy.
基金supported by NSFC(61922059,81961138014,61805140,81873609,61771314)the Terahertz Science and Technology Frontier Project(6198802).
文摘Terahertz technology has broad application prospects in biomedical detection.However, the mixed characteristics of actual samples make the terahertz spectrumcomplex and difficult to distinguish, and there is no practical terahertz detectionmethod for clinical medicine. Here, we propose a three-step one-way terahertzmodel, presenting a detailed flow analysis of terahertz technology in the biomedicaldetection of renal fibrosis as an example: 1) biomarker determination: screeningdisease biomarkers and establishing the terahertz spectrum and concentrationgradient;2) mixture interference removal: clearing the interfering signals in the mixturefor the biomarker in the animal model and evaluating and retaining the effectivecharacteristic peaks;and 3) individual difference removal: excluding individualinterference differences and confirming the final effective terahertz parameters in thehuman sample. The root mean square error of our model is three orders ofmagnitude lower than that of the gold standard, with profound implications for therapid, accurate and early detection of diseases.
基金Key Research and Development Program of China(2017YA0700201,2017YFA0700202,and 2017YFA0700201)National Natural Science Foundation of China(61631007,61571117,61501112,61501117,61522106,617310061735010,61722106,61701107,and 61701108)111 Project(111-2-05)Fund for International Cooperation and Exchange of National Natural Science Foundation of China(61761136007)。
文摘Over the past 5 years,digital coding and programmable metamaterials have beendeveloped rapidly since their first exhibition in 2014.The iconic feature of the digitalcoding metamaterial is using digital codes like"0"and"1 to represent the distinctelectromagnetic(EM)responses.This seemingly trivial progress has successfullyreform the design theory from the effective medium to coding patterns,bridgingthe physical world and digital information world.More interestingly,beyond thesimple coding on the parameters or patterns,the digital coding metamaterials aremore intend to introduce the concept of direct interactions and operations of digitalinformation within EM fields,to realize infomation processing,transmission orrecognition.Toaccurately exhibit the informational specialties,we classify the codingmetamaterials,digital metamaterials and programmable metamaterials,as well asother information-operating metamaterials,as information metamaterials In thisreview article,we fistly introduce the digital coding concept,working mechanism,and related design methods.Then,three important theories including the scatteringpattem calculation,convolution operationand entropyofdigital codingmetamaterials,arediscussed in details.Finally we introduce several system-level works based on theinfomation metamaterials,such as the new-architecture wireless communication systemsand reprogrammable imaging systems,to show the powerful manipulation capabilities ofinformation metamaterials.As the nextgeneration of infomation metamaterials,two proofof-concept smart metamaterials and their advanced architectures are discussed.In thesummary,the development track of information metamaterials and future trends are presented.
基金National Natural Science Foundation of China(NSFC)(61827825).
文摘Accurate depiction of waves in temporal and spatial is essential to the investigation of interactions between physical objects and waves.Digital holography(DH)can perform quantitative analysis of wave-matter interactions.Full detector-bandwidth reconstruc-tion can be realized based on in-line DH.But the overlapping of twin images strongly prevents quantitative analysis.For off-axis DH,the object wave and the detector bandwidth need to satisfy certain conditions to perform reconstruction accurately.Here,we present a reliable approach involving a coupled configuration for combining two in-line holograms and one off-axis hologram,using a rapidly converging iterative procedure based on two-plane coupled phase retrieval(TwPCPR)method.It realizes a fast-convergence holographic calculation method.High-resolution and full-field recon-struction by exploiting the full bandwidth are demonstrated for complex-amplitude reconstruction.Off-axis optimization phase provides an effective initial guess to avoid stagnation and minimize the required measurements of multi-plane phase retrieval.The proposed strategy works well for more extended samples without any prior assumptions of the objects including support,non-negative,sparse constraints,etc.It helps to enhance and empower applications in wavefront sensing,computational microscopy and biological tissue analysis.
基金National Natural Science Foundation of China(No.61701141,61731010)National Research Foundation,Prime Minister’s Office,Singapore(CRP award NRFCRP15–2015-03).
文摘Fourier transform, mapping the information in one domain to its reciprocal space, isof fundamental significance in real-time and parallel processing of massive data forsound and image manipulation. As a powerful platform of high-efficiency wavecontrol, Huygens’ metasurface may offer to bridge the electromagnetic signalprocessing and analog Fourier transform at the hardware level and with remarkablyimproved performance. We here demonstrate a Huygens’ metasurface hologram,where the image pattern can be self-rotated or projected in free space bymodulating the phase distribution based on the rotational invariance, time-shiftingand scaling properties of Fourier transform. Our proof-of-concept experiment showshigh-efficiency imaging operation in accordance with theoretical predictions,validating the proposed scheme as an ideal way to perform largely parallel spatialdomainmathematical operations in the analog domain using electromagnetic fields.
文摘Neuromorphic computing applies concepts extracted from neuroscience to developdevices shaped like neural systems and achieve brain-like capacity and efficiency. Inthis way, neuromorphic machines, able to learn from the surrounding environmentto deduce abstract concepts and to make decisions, promise to start a technologicalrevolution transforming our society and our life. Current electronic implementationsof neuromorphic architectures are still far from competing with their biologicalcounterparts in terms of real-time information-processing capabilities, packingdensity and energy efficiency. A solution to this impasse is represented by theapplication of photonic principles to the neuromorphic domain creating in this waythe field of neuromorphic photonics. This new field combines the advantages ofphotonics and neuromorphic architectures to build systems with high efficiency,high interconnectivity and high information density, and paves the way to ultrafast,power efficient and low cost and complex signal processing. In this Perspective, wereview the rapid development of the neuromorphic computing field both in theelectronic and in the photonic domain focusing on the role and the applications ofmemristors. We discuss the need and the possibility to conceive a photonicmemristor and we offer a positive outlook on the challenges and opportunities forthe ambitious goal of realising the next generation of full-optical neuromorphichardware.
基金Nation Science Foundation of China(Grant No.61735011).
文摘Protein assays show great importance in medical research and disease diagnoses.Liquid crystals(LCs),as a branch of sensitive materials,offer promising applicability in the field of biosensing.Herein,we developed an ultrasensitive biosensor for the detection of low-concentration protein molecules,employing LC-amplified optofluidic resonators.In this design,the orientation of LCs was disturbed by immobilized protein molecules through the reduction of the vertical anchoring force from the alignment layer.A biosensing platform based on the whispering-gallery mode(WGM)from the LC-amplified optofluidic resonator was developed and explored,in which the spectral wavelength shift was monitored as the sensing parameter.The microbubble structure provided a stable and reliable WGM resonator with a high Q factor for LCs.It is demonstrated that the wall thickness of the microbubble played a key role in enhancing the sensitivity of the LC-amplified WGM microcavity.It is also found that protein molecules coated on the internal surface of microbubble led to their interactions with laser beams and the orientation transition of LCs.Both effects amplified the target information and triggered a sensitive wavelength shift in WGM spectra.A detection limit of 1 fM for bovine serum albumin(BSA)was achieved to demonstrate the high-sensitivity of our sensing platform in protein assays.Compared to the detection using a conventional polarized optical microscope(POM),the sensitivity was improved by seven orders of magnitude.Furthermore,multiple types of proteins and specific biosensing were also investigated to verify the potential of LC-amplified optofluidic resonators in the biomolecular detection.Our studies indicate that LC-amplified optofluidic resonators offer a new solution for the ultrasensitive real-time biosensing and the characterization of biomolecular interactions.
基金H.L.acknowledges the Technology Innovation program(20016234)funded by the Ministry of Trade and Industry&Energy(MOTIE)and the National Research Foundation(NRF)grants(NRF-2019K1A4A7A02113032,NRF-2022M3H4A1A02046445,NRF-2018M3D1A1058997)funded by the Ministry of Science and ICT(MSIT)of the Korean governmentJ.R.acknowledges the POSCO-POSTECH-RIST Convergence Research Center program funded by POSCO,an industry-university strategic grant funded by Samsung Display,and the NRF grants(NRF-2022M3C1A3081312,NRF-2022M3H4A1A02074314,NRF-2019R1A5A8080290,CAMM-2019M3A6B3030637)funded by the MSIT of the Korean government+1 种基金C.W.Q.acknowledges the support by AME Individual Research Grant(IRG)funded by A*STAR,Singapore(Grant No.A2083c0060).J.K.acknowledges the POSTECH Alchemist fellowship.
文摘Nanoimprint lithography(NIL)has attracted attention recently as a promising fabrication method for dielectric metalenses owing to its low cost and high throughput,however,high aspect ratio(HAR)nanostructures are required to manipulate the full 2πphase of light.Conventional NIL using a hard-polydimethylsiloxane(h-PDMS)mold inevitably incurs shear stress on the nanostructures which is inversely proportional to the surface area parallel to the direction of detachment.Therefore,HAR structures are subjected to larger shear stresses,causing structural failure.Herein,we propose a novel wet etching NIL method with no detachment process to fabricate flawless HAR metalenses.The water-soluble replica mold is fabricated with polyvinyl alcohol(PVA)which is simpler than an h-PDMS mold,and the flexibility of the PVA mold is suitable for direct printing as its high tensile modulus allows high-resolution patterning of HAR metalenses.The diffraction-limited focusing of the printed metalenses demonstrates that it operates as an ideal lens in the visible regime.This method can potentially be used for manufacturing various nanophotonic devices that require HAR nanostructures at low cost and high throughput,facilitating commercialization.
