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Continuous roll-to-roll patterning of three-dimensional periodic nanostructures

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Microsystems & Nanoengineering 2020年第1期6卷 1067-1077页

作者： I-Te Chen Elizabeth Schappell Xiaolong Zhang Chih-Hao Chang Department of Mechanical and Aerospace Engineering North Carolina State UniversityRaleighNC 27695USA Walker Department of Mechanical Engineering University of Texas at AustinAustinTX 78712USA

In this work,we introduce a roll-to-roll system that can continuously print three-dimensional(3D)periodic nanostructures over large areas.This approach is based on Langmuir-Blodgett assembly of colloidal nanospheres,which diffract normal incident light to create a complex intensity pattern for near-field nanolithography.The geometry of the 3D nanostructure is defined by the Talbot effect and can be precisely designed by tuning the ratio of the nanosphere diameter to the exposure wavelength.Using this system,we have demonstrated patterning of 3D photonic crystals with a 500 nm period on a 50×200 mm^(2) flexible substrate,with a system throughput of 3mm/s.The patterning yield is quantitatively analyzed by an automated electron beam inspection method,demonstrating long-term repeatability of an up to 88% yield over a 4-month period.The inspection method can also be employed to examine pattern uniformity,achieving an average yield of up to 78.6% over full substrate areas.The proposed patterning method is highly versatile and scalable as a nanomanufacturing platform and can find application in nanophotonics,nanoarchitected materials,and multifunctional nanostructures.

关键词： tuning lithography periodic

A novel optical high-pressure apparatus for studying the combustion of solid propellant under periodic strain

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Science China(Technological Sciences) 2023年第3期66卷 896-900页

作者： OUYANG JianFeng GU MingMing WANG ShaoJie CUI CunHao SHI XiaoMing HOU KaiYu ZHOU ZhongYue QI Fei School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240 China Shanghai Electro-Mechanical Engineering Institute Shanghai 201109China Shanghai Academy of Spaceflight Technology Shanghai 201109China

The combustion of solid propellants can provide tremendous thrust to drive solid rocket motors.Solid propellant grains are subjected to mechanical loads during practical combustion applications.The causes of mechanical loads include,but are not limited to,impulsive loads during ignition and periodic loads(>5 Hz)due to mechanical oscillation[1,2].

关键词： periodic apparatus oscillation

Time-headway distribution for random-sequential-update TASEP with periodic and open boundaries

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Journal of Traffic and Transportation Engineering(English Edition) 2020年第1期7卷 30-41页

作者： Pavel Hrabák Faculty of Information Technology Czech Technical University in PraguePrague 16000Czechia

The temporal-headway distribution for Totally Asymmetric Simple Exclusion Process(TASEP) with random-sequential update is investigated.Considering the stationary/steady state of the process,exact formula for the step-headway distribution is derived for conditions when the stationary measure is Bernoulli,Le.,for periodic boundaries and for open boundaries with entering boundary rate α and leaving boundary rate 0 satisfying α+β=1.The step-headway formula for general values of boundary rates is calculated numerically by means of the matrix product ansatz.The formula is applicable mainly for the model defined on finite small lattice representing short segment of complex network.In this case the dependency of the motion of individual particles is noticeable and cannot be neglected.The finite lattice results are compared to continuous time distribution obtained by mans of the large L limit It can be observed that the scaled distribution converges quite fast to continuous time distribution.However,in the case of rather small lattice the distribution significantly differs from the limiting one.Moreover,in the case of Bernoulli stationary measure,the distribution is not dependent on the position of the reference site on the lattice.Considering general values of boundary parameters,the shape of the distribution is influenced by the density profile of the process near boundaries.This influence vanishes with increasing lattice size.

关键词： Transportation TASEP Time-headway distribution Random-sequential update periodic and open boundaries

A study on periodic boundary condition in direct numerical simulation for gas–solid flow

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Chinese Journal of Chemical Engineering 2020年第1期28卷 236-241页

作者： Shiwen Liu Xiaowen Liu Feiguo Chen Limin Wang Wei Ge State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China

Direct numerical simulation(DNS) of gas–solid flow at high resolution has been carried out by coupling the lattice Boltzmann method(LBM) for gas flow and the discrete element method(DEM) for solid particles. However,the body force periodic boundary condition(FPBC) commonly used to cut down the huge computational cost of such simulation has faced accuracy concerns. In this study, a novel two-region periodic boundary condition(TPBC) is presented to remedy this problem, with the flow driven in the region with body force and freely evolving in the other region. With simulation cases for simple circulating fluidized bed risers, the validity and advantages of TPBC are demonstrated with more reasonable heterogeneity of the particle distribution as compared to the corresponding case with FPBC.

关键词： Direct numerical simulation periodic boundary condition Two-region periodic boundary condition Gas–solid flow Heterogeneity

Pushing periodic-disorder-induced phase matching into the deep-ultraviolet spectral region:theory and demonstration

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Light(Science & Applications) 2020年第1期9卷 1590-1597页

作者： Mingchuan Shao Fei Liang Haohai Yu Huaijin Zhang State Key Laboratory of Crystal Materials and Institute of Crystal Materials Shandong UniversityJinan 250100China

Nonlinear frequency conversion is a ubiquitous technique that is used to obtain broad-range lasers and supercontinuum coherent sources.The phase-matching condition(momentum conservation relation)is the key criterion but a challenging bottleneck in highly efficient conversion.Birefringent phase matching(BPM)and quasiphase matching(QPM)are two feasible routes but are strongly limited in natural anisotropic crystals or ferroelectric crystals.Therefore,it is in urgent demand for a general technique that can compensate for the phase mismatching in universal nonlinear materials and in broad wavelength ranges.Here,an additional periodic phase(APP)from order/disorder alignment is proposed to meet the phase-matching condition in arbitrary nonlinear crystals and demonstrated from the visible region to the deep-ultraviolet region(e.g.,LiNbO_(3) and quartz).Remarkably,pioneering 177.3-nm coherent output is first obtained in commercial quartz crystal with an unprecedented conversion efficiency above 1‰.This study not only opens a new roadmap to resuscitate those long-neglected nonlinear optical crystals for wavelength extension,but also may revolutionize next-generation nonlinear photonics and their further applications.

关键词： matching ultraviolet periodic

Limits of topological protection under local periodic driving

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Light(Science & Applications) 2019年第1期8卷 631-642页

作者： Z.Fedorova(Cherpakova) *** C.Dauer F.Letscher M.Fleischhauer S.Eggert S.Linden Gvon Freymann Physikalisches Institut Universität Bonn53115 BonnGermany Physics Department and Research Center OPTIMAS TU Kaiserslautern67663 KaiserslauternGermany Graduate School Materials Science in Mainz 67663 KaiserslauternGermany Fraunhofer Institute for Industrial Mathematics ITWM 67663 KaiserslauternGermany

The bulk-edge correspondence guarantees that the interface between two topologically distinct insulators supports at least one topological edge state that is robust against static perturbations.Here,we address the question of how dynamic perturbations of the interface affect the robustness of edge states.We illuminate the limits of topological protection for Floquet systems in the special case of a static bulk.We use two independent dynamic quantum simulators based on coupled plasmonic and dielectric photonic waveguides to implement the topological Su-Schriefer-Heeger model with convenient control of the full space-and time-dependence of the Hamiltonian.Local time-periodic driving of the interface does not change the topological character of the system but nonetheless leads to dramatic changes of the edge state,which becomes rapidly depopulated in a certain frequency window.A theoretical Floquet analysis shows that the coupling of Floquet replicas to the bulk bands is responsible for this effect.Additionally,we determine the depopulation rate of the edge state and compare it to numerical simulations.

关键词： effect. topological periodic

Self-trapped spatially localized states in combined linear-nonlinear periodic potentials

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Frontiers of physics 2020年第1期15卷 17-24页

作者： Jin-Cheng Shi Jian-Hua Zeng State Key Laboratory of Transient Optics and Photonics Xi’an Institute of Optics and Precision Mechanics of CASXi’an 710119China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory for Physical Electronics and Devices of the Ministry of Education&Shaanxi Key Lab of Information Photonic Technique Xi’an Jiaotong UniversityXi’an 710049China

We analyze the existence and stability of two kinds of self-trapped spatially localized gap modes,gap solitons and truncated nonlinear Bloch waves,in one-and two-dimensional optical or matter-wave media with self-focusing nonlinearity,supported by a combination of linear and nonlinear periodic lattice potentials.The former is found to be stable once placed inside a single well of the nonlinear lattice,it is unstable otherwise.Contrary to the case with constant self-focusing nonlinearity,where the latter solution is always unstable,here,we demonstrate that it nevertheless can be stabilized by the nonlinear lattice since the model under consideration combines the unique properties of both the linear and nonlinear lattices.The practical possibilities for experimental realization of the predicted solutions are also discussed.

关键词： gap solitons and gap waves Bose-Einstein condensates linear and nonlinear periodic potentials

Fabrication of periodic Nanostructures Using AFM Tip-Based Nanomachining:Combining Groove and Material Pile-Up Topographies

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Engineering 2018年第6期4卷 787-795页

作者： Yanquan Geng Yongda Yan Jiqiang Wang Emmanuel Brousseau Yanwen Sun Yazhou Sun Key Laboratory of Micro-systems and Micro-structures Manufacturing of the Ministry of Education Harbin Institute of TechnologyHarbin 150001China Center for Precision Engineering Harbin Institute of TechnologyHarbin 150001China Cardiff School of Engineering Cardiff UniversityCardiff CF24 3AAUK

This paper presents an atomic force microscopy(AFM)tip-based nanomachining method to fabricate periodic nanostructures.This method relies on combining the topography generated by machined grooves with the topography resulting from accumulated pile-up material on the side of these grooves.It is shown that controlling the distance between adjacent and parallel grooves is the key factor in ensuring the quality of the resulting nanostructures.The presented experimental data show that periodic patterns with good quality can be achieved when the feed value between adjacent scratching paths is equal to the width between the two peaks of material pile-up on the sides of a single groove.The quality of the periodicity of the obtained nanostructures is evaluated by applying one-and two-dimensional fast Fourier transform(FFT)algorithms.The ratio of the area of the peak part to the total area in the normalized amplitude–frequency characteristic diagram of the cross-section of the measured AFM image is employed to quantitatively analyze the periodic nanostructures.Finally,the optical effect induced by the use of machined periodic nanostructures for surface colorization is investigated for potential applications in the fields of anti-counterfeiting and metal sensing.

关键词： Atomic force microscopy Nanomachining periodic nanostructure Single-crystal copper

Frequency-modulated continuous waves controlled by space-time-coding metasurface with nonlinearly periodic phases

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Light(Science & Applications) 2022年第10期11卷 2424-2434页

作者： Jun Chen Ke Jun Yan Dai Jun Wei Zhang Zhanye Chen Ming Zheng Chen Yunfeng Lu Lei Zhang Li Wang Qun Yan Zhou Long Li Jin Shan Ding Qiang Cheng Tie Jun Cui Institute of Electromagnetic Space Southeast University210096 NanjingChina State Key Laboratory of Millimeter Waves Southeast University210096 NanjingChina School of Electronic Engineering Xidian University710071 Xi'anChina

The rapid development of space-time-coding metasurfaces(STCMs)offers a new avenue to manipulate spatial electromagnetic beams,waveforms,and frequency spectra simultaneously with high efficiency.To date,most studies are primarily focused on harmonic generations and independent controls of finite-order harmonics and their spatial waves,but the manipulations of continuously temporal waveforms that include much rich frequency spectral components are still limited in both theory and experiment based on STCM.Here,we propose a theoretical framework and method to generate frequency-modulated continuous waves(FMCWs)and control their spatial propagation behaviors simultaneously via a novel STCM with nonlinearly periodic phases.Since the carrier frequency of FMCW changes with time rapidly,we can produce customized time-varying reflection phases at will by the required FMCW under the illumination of a monochromatic wave.More importantly,the propagation directions of the time-varying beams can be controlled by encoding the metasurface with different initial phase gradients.A programmable STCM prototype with a full-phase range is designed and fabricated to realize reprogrammable FMCW functions,and experimental results show good agreement with the theoretical analyses.

关键词： nonlinear continuous periodic