The optical manipulation of nanoparticles on superlubricity surfaces was investigated.The research revealed that,due to the near-zero static friction and extremely low dynamic friction at superlubricity interfaces,the...The optical manipulation of nanoparticles on superlubricity surfaces was investigated.The research revealed that,due to the near-zero static friction and extremely low dynamic friction at superlubricity interfaces,the maximum intensity for controlling the optical field can be less than 100 W/cm^(2).The controlled nanoparticle radius can be as small as 5 nm,which is more than one order of magnitude smaller than that of nanoparticles controlled through traditional optical manipulation.Manipulation can be achieved on sub-microsecond to microsecond timescales.Furthermore,the manipulation takes place on solid surfaces and in nonliquid environments,with minimal impact from Brownian motion.By appropriately increasing the dynamic friction,controlling the light intensity,or reducing the pressure,the effects of Brownian motion can be eliminated,allowing for the construction of microstructures with a size as small as 1/75 of the wavelength of light while controlling the light intensity,which is seven orders of magnitude smaller compared to manipulating nanoparticles on traditional surfaces.This enables the control of super-resolution optical microstructures.The optical super-resolution manipulation of nanoparticles on superlubricity surfaces has important applications in fields such as nanofabrication,photolithography,optical metasurfaces,and biochemical analysis.展开更多
Liquid crystal Pacharatnam-Berry phase optical elements(PBOEs)have found promising applications in augmented reality and virtual reality because of their slim formfactor,lightweight,and high optical efficiency.However...Liquid crystal Pacharatnam-Berry phase optical elements(PBOEs)have found promising applications in augmented reality and virtual reality because of their slim formfactor,lightweight,and high optical efficiency.However,chromatic aberration remains a serious longstanding problem for diffractive optics,hindering their broader adoption.To overcome the chromatic aberrations for red,green and blue(RGB)light sources,in this paper,we propose a counterintuitive multi-twist structure to achieve narrowband PBOEs without crosstalk,which plays a vital role to eliminate the chromatic aberration.The performance of our designed and fabricated narrowband Pacharatnam-Berry lenses(PBLs)aligns well with our simulation results.Furthermore,in a feasibility demonstration experiment using a laser projector,our proposed PBL system indeed exhibits a diminished chromatic aberration as compared to a broadband PBL.Additionally,polarization raytracing is implemented to demonstrate the versatility of the multi-twist structure for designing any RGB wavelengths with high contrast ratios.This analysis explores the feasibility of using RGB laser lines and quantum dot light-emitting diodes.Overall,our approach enables high optical efficiency,low fabrication complexity,and high degree of design freedom to accommodate any liquid crystal material and RGB light sources,holding immense potential for widespread applications of achromatic PBOEs.展开更多
We show that a metasurface composed of a subwavelength metallic slit array embedded in an asymmetric dielectric environment can exhibit either diffraction （EOD）. The cascaded refractive extraordinary optical transmi...We show that a metasurface composed of a subwavelength metallic slit array embedded in an asymmetric dielectric environment can exhibit either diffraction （EOD）. The cascaded refractive extraordinary optical transmission （EOT） or extraordinary optical indices of the dielectrics can leverage multiple decaying passages into variant subsections with different diffraction order combinations according to the diffraction order chart in the k-vector space, providing a flexible by changing the wavevector of the efficiencies can be enhanced to near or EOD in a single tional metasurface onstrated. Our findings incident light. As a result, either the unity by the excitation of the localized provide a convenient way components on a single planar device.展开更多
In this paper,a novel method is proposed and employed to design a single diffractive optical element（DOE） for implementing spectrum-splitting and beam-concentration（SSBC） functions simultaneously.We develop an opt...In this paper,a novel method is proposed and employed to design a single diffractive optical element（DOE） for implementing spectrum-splitting and beam-concentration（SSBC） functions simultaneously.We develop an optimization algorithm,through which the SSBC DOE can be optimized within an arbitrary thickness range according to the limitations of modern photolithography technology.Theoretical simulation results reveal that the designed SSBC DOE has a high optical focusing efficiency.It is expected that the designed SSBC DOE should have practical applications in high-efficiency solar cell systems.展开更多
On-chip diffractive optical neural networks(DONNs)bring the advantages of parallel processing and low energy consumption.However,an accurate representation of the optical field’s evolution in the structure cannot be ...On-chip diffractive optical neural networks(DONNs)bring the advantages of parallel processing and low energy consumption.However,an accurate representation of the optical field’s evolution in the structure cannot be provided using the previous diffraction-based analysis method.Moreover,the loss caused by the open boundaries poses challenges to applications.A multimode DONN architecture based on a more precise eigenmode analysis method is proposed.We have constructed a universal library of input,output,and metaline structures utilizing this method,and realized a multimode DONN composed of the structures from the library.On the designed multimode DONNs with only one layer of the metaline,the classification task of an Iris plants dataset is verified with an accuracy of 90%on the blind test dataset,and the performance of the one-bit binary adder task is also validated.Compared to the previous architectures,the multimode DONN exhibits a more compact design and higher energy efficiency.展开更多
The ultimate goal of artificial intelligence(AI)is to mimic the human brain to perform decision-making and control directly from high-dimensional sensory input.Diffractive optical networks(DONs)provide a promising sol...The ultimate goal of artificial intelligence(AI)is to mimic the human brain to perform decision-making and control directly from high-dimensional sensory input.Diffractive optical networks(DONs)provide a promising solution for implementing AI with high speed and low power-consumption.Most reported DONs focus on tasks that do not involve environmental interaction,such as object recognition and image classification.By contrast,the networks capable of decision-making and control have not been developed.Here,we propose using deep reinforcement learning to implement DONs that imitate human-level decisionmaking and control capability.Such networks,which take advantage of a residual architecture,allow finding optimal control policies through interaction with the environment and can be readily implemented with existing optical devices.The superior performance is verified using three types of classic games:tic-tac-toe,Super Mario Bros.,and Car Racing.Finally,we present an experimental demonstration of playing tic-tac-toe using the network based on a spatial light modulator.Our work represents a solid step forward in advancing DONs,which promises a fundamental shift from simple recognition or classification tasks to the high-level sensory capability of AI.It may find exciting applications in autonomous driving,intelligent robots,and intelligent manufacturing.展开更多
In this paper,we present the electric field controllable diffractive optical elements in strontium-barium niobate single crystals with stable tailored spiral-shaped domain structure and demonstrate the generation of o...In this paper,we present the electric field controllable diffractive optical elements in strontium-barium niobate single crystals with stable tailored spiral-shaped domain structure and demonstrate the generation of optical beam with orbital angular momentum.The required domain pattern was created in the sample with initial domain structure by electric field application using the photolithographically defined liquid electrode.A series of bipolar triangular electric field pulses were applied to the sample for determination of the optimal parameters for complete polarization switching under the electrode.The stable tailored domain pattern of the spiral shape was created by the application of the unipolar pulse of a special shape.The complete switching under the electrode and partial switching under the photoresist layer have been revealed.The imaging by Cherenkov-type second harmonic generation microscopy confirmed that the created domain structure reaches the opposite polar surface.The imaging of the diffraction pattern of the laser beam passing through a voltage-biased DOE confirmed the formation of the beam with orbital angular momentum.The half-wave voltages of 237V and 302 V for wavelength 632.8 nm and 532 nm,respectively,for 2-mmthick sample were measured.The obtained knowledge can be used for the development of domain engineering methods in strontium-barium niobate single crystals for the creation of tailored domain structures for manufacturing of electric field controllablediffractiveoptical elements.展开更多
A new distribution scheme of decryption keys used in optical verification systems is proposed. The encryption procedure is digitally implemented with the use of an iteration algorithm in computer. Three target images ...A new distribution scheme of decryption keys used in optical verification systems is proposed. The encryption procedure is digitally implemented with the use of an iteration algorithm in computer. Three target images corresponding to three wavelengths are encoded into three sets of phase-only masks （POMs） by a special distributing method. These three sets of POMs are assigned to three authorized users as the personal identification. A lensless optical system is used as the verification system. In the verification procedure, every two of the three authorized users can pass the verification procedure cooperatively, but only one user cannot do. Numerical simulation shows that the proposed distribution scheme of decryption keys not only can improve the security level of verification system, but also can bring convenience and flexibility for authorized users.展开更多
Diffractive optical elements（DOEs） with spectrum separation and beam concentration（SSBC） functions have important applications in solar cell systems. With the SSBC DOEs, the sunlight radiation is divided into seve...Diffractive optical elements（DOEs） with spectrum separation and beam concentration（SSBC） functions have important applications in solar cell systems. With the SSBC DOEs, the sunlight radiation is divided into several wave bands so as to be effectively absorbed by photovoltaic materials with different band gaps. A new method is proposed for designing high-efficiency SSBC DOEs, which is physically simple, numerically fast, and universally applicable. The SSBC DOEs are designed by the new design method, and their performances are analyzed by the Fresnel diffraction integral method.The new design method takes two advantages over the previous design method. Firstly, the optical focusing efficiency is heightened by up to 10%. Secondly, focal positions of all the designed wavelengths can be designated arbitrarily and independently. It is believed that the designed SSBC DOEs should have practical applications to solar cell systems.展开更多
Based on the facts that multijunction solar cells can increase the efficiency and concentration can reduce the cost dramatically, a special design of parallel multijunction solar cells was presented. The design employ...Based on the facts that multijunction solar cells can increase the efficiency and concentration can reduce the cost dramatically, a special design of parallel multijunction solar cells was presented. The design employed a diffractive optical element （DOE） to split and concentrate the sunlight. A rainbow region and a zero-order diffraction region were generated on the output plane where solar cells with corresponding band gaps were placed. An analytical expression of the light intensity distribution on the output plane of the special DOE was deduced, and the limiting photovoltaic efficiency of such parallel multijunction solar ceils was obtained based on Shockley-Queisser＇s theory. An efficiency exceeding the Shockley--Queisser limit （33%） can be expected using multijunction solar cells consisting of separately fabricated subcells. The results provide an important alternative approach to realize high photovoltaic efficiency without the need for expensive epitaxial technology widely used in tandem solar cells, thus stimulating the research and application of high efficiency and low cost solar cells.展开更多
Thin films of zinc-doped cadmium oxide with different Zn-doping levels（0, 2, 4, 6, and 8 at%） were deposited on glass substrates by employing an inexpensive, simplified spray technique using perfume atomizer at rela...Thin films of zinc-doped cadmium oxide with different Zn-doping levels（0, 2, 4, 6, and 8 at%） were deposited on glass substrates by employing an inexpensive, simplified spray technique using perfume atomizer at relatively low substrate temperature（375 °C） compared with the conventional spray method. The effect of Zn doping on the structural,morphological, optical, and electrical properties of the films was investigated. XRD patterns revealed that all the films are polycrystalline in nature having cubic crystal structure with a preferential orientation along the（1 1 1） plane irrespective of Zn-doping level. Zn-doping level causes a slight shift in the（1 1 1） diffraction peak toward higher angle. The crystallite size of the films was found to be in the range of 28–37 nm. The band gap value increases with Zn doping and reaches a maximum of 2.65 eV for the film coated with 6 at% Zn doping and for further higher doping concentration it decreases.Electrical studies indicate that Zn doping causes a reduction in the resistivity of the films and a minimum resistivity of15.69 X cm is observed for the film coated with 6 at% Zn.展开更多
Two improved algorithms are proposed to extend a diffractive optical element （DOE） to work under the broad spec- trum of sunlight. An optimum design has been found for the DOE, with a weighted average optical effici...Two improved algorithms are proposed to extend a diffractive optical element （DOE） to work under the broad spec- trum of sunlight. An optimum design has been found for the DOE, with a weighted average optical efficiency of about 6.8% better than that of the previous design. The optimization of designing high optical efficiency DOEs will pave the way for future designs of high-efficiency, low-cost lateral multijunction solar cells based on such a DOE.展开更多
Based on a modified coupled wave theory of Kogelnik, we have studied the diffraction of an ultrashort pulsed beam with an arbitrary polarization state from a volume holographic grating in photorefractive LiNbO3 crysta...Based on a modified coupled wave theory of Kogelnik, we have studied the diffraction of an ultrashort pulsed beam with an arbitrary polarization state from a volume holographic grating in photorefractive LiNbO3 crystals. The results indicate that the diffracted intensity distributions in the spectral and temporal domains and the diffraction efficiency of the grating are both changed by the polarization state and spectral bandwidth of the input pulsed beam. A method is given of choosing the grating parameters and input conditions to obtain a large variation range of the spectral bandwidth of the diffracted pulsed beam with an appropriate diffraction efficiency. Our study presents a possibility of using a volume holographic grating recorded in anisotropic materials to shape a broadband ultrashort pulsed beam by modulating its polarization state.展开更多
The oxidation of aluminium was studied using optical emission spectroscopy （OES） during the evaporation of aluminium in traces of oxygen in a thermal plasma reactor. The ratio of the measured line intensities of Al-...The oxidation of aluminium was studied using optical emission spectroscopy （OES） during the evaporation of aluminium in traces of oxygen in a thermal plasma reactor. The ratio of the measured line intensities of Al-O with that of Al follows the exact trend as of that obtained from the corresponding line intensities in X-ray diffraction spectra of the synthesized samples. In this paper the inherent capacity of emission spectroscopy in evaluating the growth processes under plasma induced reactions is presented.展开更多
In the Fresnel transform domain, an effective improvement to the conventional iterative algorithm for designing the diffractive optical elements (DOEs) used for spatial beam shaping has been proposed. The algorithm ca...In the Fresnel transform domain, an effective improvement to the conventional iterative algorithm for designing the diffractive optical elements (DOEs) used for spatial beam shaping has been proposed. The algorithm can successfully achieve to design DOEs for beam shaping. Compared with conventional algorithm, this algorithm can provide faster convergence, more powerful ability to overcome local minimum problem and better shaping quality. By computer simulation, the result has shown that the DOEs designed by this algorithm has snch advantages as high uniformity at the main lobe, low profile error and steep edge.展开更多
1 Introduction 1.1 Advantages of DOE 1)High diffraction efficiency; 2)Dispersive; 3)More selectivity of designing parameters; 4)More selectivity of primary materials; 5)Can make components miniature,forming array and ...1 Introduction 1.1 Advantages of DOE 1)High diffraction efficiency; 2)Dispersive; 3)More selectivity of designing parameters; 4)More selectivity of primary materials; 5)Can make components miniature,forming array and integration. 1.2 1.3 megapixel triplet plastic mobile展开更多
The photo-kinetics of fluorescent molecules have enabled the circumvention of the far-field optical diffraction limit.Despite its enormous potential,the necessity to label the sample may adversely influence the delica...The photo-kinetics of fluorescent molecules have enabled the circumvention of the far-field optical diffraction limit.Despite its enormous potential,the necessity to label the sample may adversely influence the delicate biology under investigation.Thus,continued development efforts are needed to surpass the far-field label-free diffraction barrier.The statistical similarity or finite coherence of the scattered light off the sample in label-free mode hinders the application of existing super-resolution methods based on incoherent fluorescence imaging.In this article,we present physics and propose a methodology to circumvent this challenge by exploiting the photoluminescence(PL)of silicon nitride waveguides for near-field illumination of unlabeled samples.The technique is abbreviated EPSLON,Evanescently decaying Photoluminescence Scattering enables Label-free Optical Nanoscopy.We demonstrate that such an illumination has properties that mimic the photo-kinetics of nano-sized fluorescent molecules,i.e.,such an illumination permits incoherence between the scattered fields from various locations on the sample plane.Thus,the illumination scheme enables the development of a far-field label-free incoherent imaging system that is linear in intensity and stable over time,thereby permitting the application of techniques like structured illumination microscopy(SIM)and intensity-fluctuation-based optical nanoscopy(IFON)in label-free mode to circumvent the diffraction limit.In this proof-of-concept work,we observed a two-point resolution of~180 nm on super-resolved nanobeads and resolution improvements between 1.9×to 2.8×over the diffraction limit,as quantified using Fourier Ring Correlation(FRC),on various biological samples.We believe EPSLON is a step forward within the field of incoherent far-field label-free super-resolution microscopy that holds a key to investigating biological systems in their natural state without the need for exogenous labels.展开更多
As an optical processor,a diffractive deep neural network(D2NN)utilizes engineered diffractive surfaces designed through machine learning to perform all-optical information processing,completing its tasks at the speed...As an optical processor,a diffractive deep neural network(D2NN)utilizes engineered diffractive surfaces designed through machine learning to perform all-optical information processing,completing its tasks at the speed of light propagation through thin optical layers.With sufficient degrees of freedom,D2NNs can perform arbitrary complex-valued linear transformations using spatially coherent light.Similarly,D2NNs can also perform arbitrary linear intensity transformations with spatially incoherent illumination;however,under spatially incoherent light,these transformations are nonnegative,acting on diffraction-limited optical intensity patterns at the input field of view.Here,we expand the use of spatially incoherent D2NNs to complex-valued information processing for executing arbitrary complex-valued linear transformations using spatially incoherent light.Through simulations,we show that as the number of optimized diffractive features increases beyond a threshold dictated by the multiplication of the input and output space-bandwidth products,a spatially incoherent diffractive visual processor can approximate any complex-valued linear transformation and be used for all-optical image encryption using incoherent illumination.The findings are important for the all-optical processing of information under natural light using various forms of diffractive surface-based optical processors.展开更多
Vector structured beams(VSBs)offer infinite eigenstates and open up new possibilities for highcapacity optical and quantum communications by the multiplexing of the states.Therefore,the sorting and measuring of VSBs a...Vector structured beams(VSBs)offer infinite eigenstates and open up new possibilities for highcapacity optical and quantum communications by the multiplexing of the states.Therefore,the sorting and measuring of VSBs are extremely important.However,the efficient manipulations of a large number of VSBs have simultaneously remained challenging up to now,especially in integrated optical systems.Here,we propose a compact spin-multiplexed diffractive metasurface capable of continuously sorting and detecting arbitrary VSBs through spatial intensity separation.By introducing a diffractive optical neural network with cascaded metasurface systems,we demonstrate arbitrary VSBs sorters that can simultaneously identify Laguerre–Gaussian modes(l=−4 to 4,p=1 to 4),Hermitian–Gaussian modes(m=1 to 4,n=1 to 3),and Bessel–Gaussian modes(l=1 to 12).Such a sorter for arbitrary VSBs could revolutionize applications in integrated and high-dimensional optical communication systems.展开更多
We present a broadband and polarization-insensitive unidirectional imager that operates at the visible part of the spectrum,where image formation occurs in one direction,while in the opposite direction,it is blocked.T...We present a broadband and polarization-insensitive unidirectional imager that operates at the visible part of the spectrum,where image formation occurs in one direction,while in the opposite direction,it is blocked.This approach is enabled by deep learning-driven diffractive optical design with wafer-scale nano-fabrication using high-purity fused silica to ensure optical transparency and thermal stability.Our design achieves unidirectional imaging across three visible wavelengths(covering red,green,and blue parts of the spectrum),and we experimentally validated this broadband unidirectional imager by creating high-fidelity images in the forward direction and generating weak,distorted output patterns in the backward direction,in alignment with our numerical simulations.This work demonstrates wafer-scale production of diffractive optical processors,featuring 16 levels of nanoscale phase features distributed across two axially aligned diffractive layers for visible unidirectional imaging.This approach facilitates mass-scale production of~0.5 billion nanoscale phase features per wafer,supporting high-throughput manufacturing of hundreds to thousands of multi-layer diffractive processors suitable for large apertures and parallel processing of multiple tasks.Beyond broadband unidirectional imaging in the visible spectrum,this study establishes a pathway for artificial-intelligence-enabled diffractive optics with versatile applications,signaling a new era in optical device functionality with industrial-level,massively scalable fabrication.展开更多
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.62174040 and 12174423)the 13th Batch of Outstanding Young Scientific and Technological Talents Project in Guizhou Province(No.[2021]5618)+1 种基金the Science and Technology Projects of Guizhou Provincial(No.ZK[2024]501)the Scientific Research Fund of Guizhou Minzu University(No.GZMUZK[2023]CXTD07).
文摘The optical manipulation of nanoparticles on superlubricity surfaces was investigated.The research revealed that,due to the near-zero static friction and extremely low dynamic friction at superlubricity interfaces,the maximum intensity for controlling the optical field can be less than 100 W/cm^(2).The controlled nanoparticle radius can be as small as 5 nm,which is more than one order of magnitude smaller than that of nanoparticles controlled through traditional optical manipulation.Manipulation can be achieved on sub-microsecond to microsecond timescales.Furthermore,the manipulation takes place on solid surfaces and in nonliquid environments,with minimal impact from Brownian motion.By appropriately increasing the dynamic friction,controlling the light intensity,or reducing the pressure,the effects of Brownian motion can be eliminated,allowing for the construction of microstructures with a size as small as 1/75 of the wavelength of light while controlling the light intensity,which is seven orders of magnitude smaller compared to manipulating nanoparticles on traditional surfaces.This enables the control of super-resolution optical microstructures.The optical super-resolution manipulation of nanoparticles on superlubricity surfaces has important applications in fields such as nanofabrication,photolithography,optical metasurfaces,and biochemical analysis.
基金supports from the National Key Research and Development Program of China(2023YFB2806803)the National Natural Science Foundation of China(62075127).
文摘Liquid crystal Pacharatnam-Berry phase optical elements(PBOEs)have found promising applications in augmented reality and virtual reality because of their slim formfactor,lightweight,and high optical efficiency.However,chromatic aberration remains a serious longstanding problem for diffractive optics,hindering their broader adoption.To overcome the chromatic aberrations for red,green and blue(RGB)light sources,in this paper,we propose a counterintuitive multi-twist structure to achieve narrowband PBOEs without crosstalk,which plays a vital role to eliminate the chromatic aberration.The performance of our designed and fabricated narrowband Pacharatnam-Berry lenses(PBLs)aligns well with our simulation results.Furthermore,in a feasibility demonstration experiment using a laser projector,our proposed PBL system indeed exhibits a diminished chromatic aberration as compared to a broadband PBL.Additionally,polarization raytracing is implemented to demonstrate the versatility of the multi-twist structure for designing any RGB wavelengths with high contrast ratios.This analysis explores the feasibility of using RGB laser lines and quantum dot light-emitting diodes.Overall,our approach enables high optical efficiency,low fabrication complexity,and high degree of design freedom to accommodate any liquid crystal material and RGB light sources,holding immense potential for widespread applications of achromatic PBOEs.
基金National Natural Science Foundation of China(NSFC)(11604217,11574218,11734012,61420106014,61522504)Fundamental Research Funds for the Central Universities(21617410)Guangdong Provincial Innovation and Entrepreneurship Project(2016ZT06D081)
文摘We show that a metasurface composed of a subwavelength metallic slit array embedded in an asymmetric dielectric environment can exhibit either diffraction （EOD）. The cascaded refractive extraordinary optical transmission （EOT） or extraordinary optical indices of the dielectrics can leverage multiple decaying passages into variant subsections with different diffraction order combinations according to the diffraction order chart in the k-vector space, providing a flexible by changing the wavevector of the efficiencies can be enhanced to near or EOD in a single tional metasurface onstrated. Our findings incident light. As a result, either the unity by the excitation of the localized provide a convenient way components on a single planar device.
基金Project supported by the National Basic Research Program of China (Grant No. 2011CB301801)the National Natural Science Foundation of China (GrantNos. 91233202,10904099,11204188,61205097,and 11174211)
文摘In this paper,a novel method is proposed and employed to design a single diffractive optical element（DOE） for implementing spectrum-splitting and beam-concentration（SSBC） functions simultaneously.We develop an optimization algorithm,through which the SSBC DOE can be optimized within an arbitrary thickness range according to the limitations of modern photolithography technology.Theoretical simulation results reveal that the designed SSBC DOE has a high optical focusing efficiency.It is expected that the designed SSBC DOE should have practical applications in high-efficiency solar cell systems.
基金supported by the National Natural Science Foundation of China (Grant No.62135009)the Beijing Municipal Science and Technology Commission,Administrative Commission of Zhongguancun Science Park (Grant No.Z221100005322010).
文摘On-chip diffractive optical neural networks(DONNs)bring the advantages of parallel processing and low energy consumption.However,an accurate representation of the optical field’s evolution in the structure cannot be provided using the previous diffraction-based analysis method.Moreover,the loss caused by the open boundaries poses challenges to applications.A multimode DONN architecture based on a more precise eigenmode analysis method is proposed.We have constructed a universal library of input,output,and metaline structures utilizing this method,and realized a multimode DONN composed of the structures from the library.On the designed multimode DONNs with only one layer of the metaline,the classification task of an Iris plants dataset is verified with an accuracy of 90%on the blind test dataset,and the performance of the one-bit binary adder task is also validated.Compared to the previous architectures,the multimode DONN exhibits a more compact design and higher energy efficiency.
基金supported by the National Natural Science Foundation of China(Grant Nos.12064025,12264028,12364045,and 12304420)the Natural Science Foundation of Jiangxi Province(Grant Nos.20212ACB202006,20232BAB201040,and 20232BAB211025)+3 种基金the Shanghai Pujiang Program(Grant No.22PJ1402900)the Australian Research Council Discovery Project(Grant No.DP200101353)the Interdisciplinary Innovation Fund of Nanchang University(Grant No.2019-9166-27060003)the China Scholarship Council(Grant No.202008420045).
文摘The ultimate goal of artificial intelligence(AI)is to mimic the human brain to perform decision-making and control directly from high-dimensional sensory input.Diffractive optical networks(DONs)provide a promising solution for implementing AI with high speed and low power-consumption.Most reported DONs focus on tasks that do not involve environmental interaction,such as object recognition and image classification.By contrast,the networks capable of decision-making and control have not been developed.Here,we propose using deep reinforcement learning to implement DONs that imitate human-level decisionmaking and control capability.Such networks,which take advantage of a residual architecture,allow finding optimal control policies through interaction with the environment and can be readily implemented with existing optical devices.The superior performance is verified using three types of classic games:tic-tac-toe,Super Mario Bros.,and Car Racing.Finally,we present an experimental demonstration of playing tic-tac-toe using the network based on a spatial light modulator.Our work represents a solid step forward in advancing DONs,which promises a fundamental shift from simple recognition or classification tasks to the high-level sensory capability of AI.It may find exciting applications in autonomous driving,intelligent robots,and intelligent manufacturing.
基金support of the Ministry of Science and Higher Education of the Russian Federation(state task FEUZ-2023-0017)The equipment of the Ural Center for Shared Use“"Modern nanotechnology"Ural Federal University(Reg.No 2968)was used.
文摘In this paper,we present the electric field controllable diffractive optical elements in strontium-barium niobate single crystals with stable tailored spiral-shaped domain structure and demonstrate the generation of optical beam with orbital angular momentum.The required domain pattern was created in the sample with initial domain structure by electric field application using the photolithographically defined liquid electrode.A series of bipolar triangular electric field pulses were applied to the sample for determination of the optimal parameters for complete polarization switching under the electrode.The stable tailored domain pattern of the spiral shape was created by the application of the unipolar pulse of a special shape.The complete switching under the electrode and partial switching under the photoresist layer have been revealed.The imaging by Cherenkov-type second harmonic generation microscopy confirmed that the created domain structure reaches the opposite polar surface.The imaging of the diffraction pattern of the laser beam passing through a voltage-biased DOE confirmed the formation of the beam with orbital angular momentum.The half-wave voltages of 237V and 302 V for wavelength 632.8 nm and 532 nm,respectively,for 2-mmthick sample were measured.The obtained knowledge can be used for the development of domain engineering methods in strontium-barium niobate single crystals for the creation of tailored domain structures for manufacturing of electric field controllablediffractiveoptical elements.
文摘A new distribution scheme of decryption keys used in optical verification systems is proposed. The encryption procedure is digitally implemented with the use of an iteration algorithm in computer. Three target images corresponding to three wavelengths are encoded into three sets of phase-only masks （POMs） by a special distributing method. These three sets of POMs are assigned to three authorized users as the personal identification. A lensless optical system is used as the verification system. In the verification procedure, every two of the three authorized users can pass the verification procedure cooperatively, but only one user cannot do. Numerical simulation shows that the proposed distribution scheme of decryption keys not only can improve the security level of verification system, but also can bring convenience and flexibility for authorized users.
基金Project supported by the National Basic Research Program of China(Grant No.2013CBA01702)the National Natural Science Foundation of China(Grant Nos.11474206,91233202,11374216,and 11404224)+1 种基金the Scientific Research Project of Beijing Education Commission,China(Grant No.KM201310028005)the Scientific Research Base Development Program of the Beijing Municipal Commission of Education and the Beijing Youth Top-Notch Talent Training Plan,China(Grant No.CIT&TCD201504080)
文摘Diffractive optical elements（DOEs） with spectrum separation and beam concentration（SSBC） functions have important applications in solar cell systems. With the SSBC DOEs, the sunlight radiation is divided into several wave bands so as to be effectively absorbed by photovoltaic materials with different band gaps. A new method is proposed for designing high-efficiency SSBC DOEs, which is physically simple, numerically fast, and universally applicable. The SSBC DOEs are designed by the new design method, and their performances are analyzed by the Fresnel diffraction integral method.The new design method takes two advantages over the previous design method. Firstly, the optical focusing efficiency is heightened by up to 10%. Secondly, focal positions of all the designed wavelengths can be designated arbitrarily and independently. It is believed that the designed SSBC DOEs should have practical applications to solar cell systems.
基金supported by the National Natural Science Foundation of China(Grant Nos.91233202,21173260,and 51072221)the National Basic Research Program of China(Grant No.2012CB932903)
文摘Based on the facts that multijunction solar cells can increase the efficiency and concentration can reduce the cost dramatically, a special design of parallel multijunction solar cells was presented. The design employed a diffractive optical element （DOE） to split and concentrate the sunlight. A rainbow region and a zero-order diffraction region were generated on the output plane where solar cells with corresponding band gaps were placed. An analytical expression of the light intensity distribution on the output plane of the special DOE was deduced, and the limiting photovoltaic efficiency of such parallel multijunction solar ceils was obtained based on Shockley-Queisser＇s theory. An efficiency exceeding the Shockley--Queisser limit （33%） can be expected using multijunction solar cells consisting of separately fabricated subcells. The results provide an important alternative approach to realize high photovoltaic efficiency without the need for expensive epitaxial technology widely used in tandem solar cells, thus stimulating the research and application of high efficiency and low cost solar cells.
文摘Thin films of zinc-doped cadmium oxide with different Zn-doping levels（0, 2, 4, 6, and 8 at%） were deposited on glass substrates by employing an inexpensive, simplified spray technique using perfume atomizer at relatively low substrate temperature（375 °C） compared with the conventional spray method. The effect of Zn doping on the structural,morphological, optical, and electrical properties of the films was investigated. XRD patterns revealed that all the films are polycrystalline in nature having cubic crystal structure with a preferential orientation along the（1 1 1） plane irrespective of Zn-doping level. Zn-doping level causes a slight shift in the（1 1 1） diffraction peak toward higher angle. The crystallite size of the films was found to be in the range of 28–37 nm. The band gap value increases with Zn doping and reaches a maximum of 2.65 eV for the film coated with 6 at% Zn doping and for further higher doping concentration it decreases.Electrical studies indicate that Zn doping causes a reduction in the resistivity of the films and a minimum resistivity of15.69 X cm is observed for the film coated with 6 at% Zn.
基金Project supported by the National Natural Science Foundation of China(Grants Nos.91233202,21173260,and 51072221)the National Basic Research Program of China(Grant No.2012CB932903
文摘Two improved algorithms are proposed to extend a diffractive optical element （DOE） to work under the broad spec- trum of sunlight. An optimum design has been found for the DOE, with a weighted average optical efficiency of about 6.8% better than that of the previous design. The optimization of designing high optical efficiency DOEs will pave the way for future designs of high-efficiency, low-cost lateral multijunction solar cells based on such a DOE.
基金Project supported by the State Key Development Program for Basic Research of China （Grant No 2002CCA03500）, and the National Natural Science Foundation of China （Grant No 60177016）.
文摘Based on a modified coupled wave theory of Kogelnik, we have studied the diffraction of an ultrashort pulsed beam with an arbitrary polarization state from a volume holographic grating in photorefractive LiNbO3 crystals. The results indicate that the diffracted intensity distributions in the spectral and temporal domains and the diffraction efficiency of the grating are both changed by the polarization state and spectral bandwidth of the input pulsed beam. A method is given of choosing the grating parameters and input conditions to obtain a large variation range of the spectral bandwidth of the diffracted pulsed beam with an appropriate diffraction efficiency. Our study presents a possibility of using a volume holographic grating recorded in anisotropic materials to shape a broadband ultrashort pulsed beam by modulating its polarization state.
基金support rendered by BRNS (DAE, India) for the project
文摘The oxidation of aluminium was studied using optical emission spectroscopy （OES） during the evaporation of aluminium in traces of oxygen in a thermal plasma reactor. The ratio of the measured line intensities of Al-O with that of Al follows the exact trend as of that obtained from the corresponding line intensities in X-ray diffraction spectra of the synthesized samples. In this paper the inherent capacity of emission spectroscopy in evaluating the growth processes under plasma induced reactions is presented.
文摘In the Fresnel transform domain, an effective improvement to the conventional iterative algorithm for designing the diffractive optical elements (DOEs) used for spatial beam shaping has been proposed. The algorithm can successfully achieve to design DOEs for beam shaping. Compared with conventional algorithm, this algorithm can provide faster convergence, more powerful ability to overcome local minimum problem and better shaping quality. By computer simulation, the result has shown that the DOEs designed by this algorithm has snch advantages as high uniformity at the main lobe, low profile error and steep edge.
文摘1 Introduction 1.1 Advantages of DOE 1)High diffraction efficiency; 2)Dispersive; 3)More selectivity of designing parameters; 4)More selectivity of primary materials; 5)Can make components miniature,forming array and integration. 1.2 1.3 megapixel triplet plastic mobile
文摘The photo-kinetics of fluorescent molecules have enabled the circumvention of the far-field optical diffraction limit.Despite its enormous potential,the necessity to label the sample may adversely influence the delicate biology under investigation.Thus,continued development efforts are needed to surpass the far-field label-free diffraction barrier.The statistical similarity or finite coherence of the scattered light off the sample in label-free mode hinders the application of existing super-resolution methods based on incoherent fluorescence imaging.In this article,we present physics and propose a methodology to circumvent this challenge by exploiting the photoluminescence(PL)of silicon nitride waveguides for near-field illumination of unlabeled samples.The technique is abbreviated EPSLON,Evanescently decaying Photoluminescence Scattering enables Label-free Optical Nanoscopy.We demonstrate that such an illumination has properties that mimic the photo-kinetics of nano-sized fluorescent molecules,i.e.,such an illumination permits incoherence between the scattered fields from various locations on the sample plane.Thus,the illumination scheme enables the development of a far-field label-free incoherent imaging system that is linear in intensity and stable over time,thereby permitting the application of techniques like structured illumination microscopy(SIM)and intensity-fluctuation-based optical nanoscopy(IFON)in label-free mode to circumvent the diffraction limit.In this proof-of-concept work,we observed a two-point resolution of~180 nm on super-resolved nanobeads and resolution improvements between 1.9×to 2.8×over the diffraction limit,as quantified using Fourier Ring Correlation(FRC),on various biological samples.We believe EPSLON is a step forward within the field of incoherent far-field label-free super-resolution microscopy that holds a key to investigating biological systems in their natural state without the need for exogenous labels.
基金support of the U.S.Department of Energy (DOE),Office of Basic Energy Sciences,Division of Materials Sciences and Engineering under Award#DE-SC0023088.
文摘As an optical processor,a diffractive deep neural network(D2NN)utilizes engineered diffractive surfaces designed through machine learning to perform all-optical information processing,completing its tasks at the speed of light propagation through thin optical layers.With sufficient degrees of freedom,D2NNs can perform arbitrary complex-valued linear transformations using spatially coherent light.Similarly,D2NNs can also perform arbitrary linear intensity transformations with spatially incoherent illumination;however,under spatially incoherent light,these transformations are nonnegative,acting on diffraction-limited optical intensity patterns at the input field of view.Here,we expand the use of spatially incoherent D2NNs to complex-valued information processing for executing arbitrary complex-valued linear transformations using spatially incoherent light.Through simulations,we show that as the number of optimized diffractive features increases beyond a threshold dictated by the multiplication of the input and output space-bandwidth products,a spatially incoherent diffractive visual processor can approximate any complex-valued linear transformation and be used for all-optical image encryption using incoherent illumination.The findings are important for the all-optical processing of information under natural light using various forms of diffractive surface-based optical processors.
基金supported by the National Natural Science Foundation of China(Grant No.12274105)the Heilongjiang Natural Science Funds for Distinguished Young Scholars(Grant No.JQ2022A001)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.HIT.OCEF.2021020)the Joint Guidance Project of the Natural Science Foundation of Heilongjiang Province(Grant No.LH2023A006).
文摘Vector structured beams(VSBs)offer infinite eigenstates and open up new possibilities for highcapacity optical and quantum communications by the multiplexing of the states.Therefore,the sorting and measuring of VSBs are extremely important.However,the efficient manipulations of a large number of VSBs have simultaneously remained challenging up to now,especially in integrated optical systems.Here,we propose a compact spin-multiplexed diffractive metasurface capable of continuously sorting and detecting arbitrary VSBs through spatial intensity separation.By introducing a diffractive optical neural network with cascaded metasurface systems,we demonstrate arbitrary VSBs sorters that can simultaneously identify Laguerre–Gaussian modes(l=−4 to 4,p=1 to 4),Hermitian–Gaussian modes(m=1 to 4,n=1 to 3),and Bessel–Gaussian modes(l=1 to 12).Such a sorter for arbitrary VSBs could revolutionize applications in integrated and high-dimensional optical communication systems.
基金Ozcan Lab at UCLA acknowledges the U.S.Department of Energy(DOE),Office of Basic Energy Sciences,Division of Materials Sciences and Engineering under award no.DE-SC0023088.
文摘We present a broadband and polarization-insensitive unidirectional imager that operates at the visible part of the spectrum,where image formation occurs in one direction,while in the opposite direction,it is blocked.This approach is enabled by deep learning-driven diffractive optical design with wafer-scale nano-fabrication using high-purity fused silica to ensure optical transparency and thermal stability.Our design achieves unidirectional imaging across three visible wavelengths(covering red,green,and blue parts of the spectrum),and we experimentally validated this broadband unidirectional imager by creating high-fidelity images in the forward direction and generating weak,distorted output patterns in the backward direction,in alignment with our numerical simulations.This work demonstrates wafer-scale production of diffractive optical processors,featuring 16 levels of nanoscale phase features distributed across two axially aligned diffractive layers for visible unidirectional imaging.This approach facilitates mass-scale production of~0.5 billion nanoscale phase features per wafer,supporting high-throughput manufacturing of hundreds to thousands of multi-layer diffractive processors suitable for large apertures and parallel processing of multiple tasks.Beyond broadband unidirectional imaging in the visible spectrum,this study establishes a pathway for artificial-intelligence-enabled diffractive optics with versatile applications,signaling a new era in optical device functionality with industrial-level,massively scalable fabrication.
