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Optical Bistability in incident-Dependent Two-Dimensional Nonlinear Optical Superlattices

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Chinese Physics Letters 1996年第12期13卷 913-915页

作者： CHEN Xiang-fei LU Ya-lin LU Yan-qing MIN Nai-ben National Laboratory of Solid State Microstructures Nanjing UniversityNanjing 210093 CCAST(World Laboratory) P.O.Box 8730Beijing 100080

It is shown that,when two coherent waves are obliquely incident to a one-dimensional nonlinear optical superlattice containing Kerr-form dielectric nonlinearity,an incident-dependent two-dimensional nonlinear optical superlattice can be constructed.This structure can be bistable.There exist two types of optical bistable mechanism,i.e.,the index-modulation mechanism and distributed feedback mechanism.Owing to the index-modulation mechanism,the threshold for the bistability is lower than that of a more traditional one-dimensional distributed feedback structure.

关键词： mechanism structure incident

Wave Optics in Discrete Excitable Media

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Chinese Physics Letters 2012年第5期29卷 107-110页

作者：顾国锋韦海明唐国宁 College of Physics Science and Technology Guangxi Normal UniversityGuilin 541004

Refraction and reflection of planar waves in a discrete excitable medium is numerically investigated by using the Greenberg-Hasting model.It is fonnd that the medium is anisotropic because the speed of the planar wave depends on the excitability of the medium and the direction of wave propagation.The reflection,diffraction,refraction,double refraction and delayed refraction are observed by using the correct choice of model parameters.When the incident angle is larger than the critical angle,the reflection,which is a back refraction,takes place.The reflection angle changes with the incident angle.The refraction in certain situations obeys Shell's law.Also,our results demonstrate that the incident,refracted and reflected waves can have different periods.The reflected and refracted waves can disappear.

关键词： parameters. refraction incident

Topological Charge Conversion with Spiral-Slit Screens

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Chinese Physics Letters 2013年第10期30卷 108-111页

作者：李振华张美娜李杏刘春香程传福 College of Physics and Electronics Shandong Normal UniversityJinan 250014

We propose a method of converting the topological charge(TC)of an incident vortex light wave with spiral-slit screens.The phase in the incident vortex beam is redistributed via the optical path adjustment realized by changing the in-plane radial distance of the spiral slit.We numerically calculate the light field with Fresnel diffraction theory,and find the expected TC conversion on the observation plane.Our calculations also show that screens of pinholes distributed in a spiral curve can be used for the implementation instead of spiral slits.The method can also be used to distinguish the TCs of the incident vortices by reading the diffracted intensity patterns.

关键词： incident vortex topological

Recovering Unbounded Rough Surfaces with a Direct Imaging Method

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Acta Mathematicae Applicatae Sinica 2020年第1期36卷 119-133页

作者： Hai-wen ZHANG NCMIS and Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100190China

In this paper,we consider the inverse acoustic scattering problem by an unbounded rough surface.A direct imaging method is proposed to reconstruct the rough surfaces from scattered-field data for incident plane waves and the performance analysis is also presented.The reconstruction method is very robust to noises of measured data and does’t need to know the type of the boundary conditions of the surfaces in advance.Finally,numerical examples are carried out to illustrate that our method is fast,accurate and stable even for the case of multiple-scale profiles.

关键词： direct imaging method inverse scattering problem unbounded rough surface incident plane wave near-field data

A procedure to predict the precise seismic response of arch dams in time domain using boundary element formulation

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第4期11卷 790-803页

作者： Abbasali TaghaviGhalesari Mohsen Isari Reza Tarinejad Abdollah Sohrabi-Bidar Center for Transportation Infrastructure Systems University of Texas at El PasoEl PasoTX79968USA Faculty of Civil Engineering University of TabrizTabriz***Iran School of Geology University College of ScienceUniversity of TehranTehran14155-6619Iran

In this context,a new boundary element algorithm based on the time-convoluted traction kernels is employed to evaluate the spatially varying earthquake ground motions of the Pacoima dam in the USA subjected to SH,SV and P incident waves.An accurate three-dimensional (3D) model of the dam canyon is implemented into the computer code BEMSA to investigate the seismic response of the dam.The analyses are performed in time domain with a linearly elastic constitutive model for the medium.This modeling procedure has been validated by the results reported in the existing literature.According to the results of this study,the response of the dam to earthquake waves is generally influenced by predominant frequency of the incident motion,surface topography,relative distance of observation points,and type of the incident seismic wave.For the cases considered,the incident SV wave has led to the maximum amplification of incident motions,especially at the left side of the dam.The results indicate that the proposed procedure can be employed for accurate prediction of a dam response during an earthquake.

关键词： Boundary element method Spatially varying earthquake ground motion Pacoima dam Topography incident wave

Inelastic Scattering of ^(32)Mg at 190 MeV/Nucleon from a Thick Proton Target

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Chinese Physics Letters 2012年第10期29卷 28-30页

作者：李阔昂叶沿林 Heiko SCHEIT Pieter DOORNENBAL 武内聡青井考松下昌史竹下英里本林透櫻井博儀庞丹阳 School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing 100871 RIKEN Nishina Center WakoSaitama351-0198Japan School of Physics and Nuclear Energy Engineering Beihang UniversityBeijing 100191

The first excited 2^(+)state(885 keV)of ^(32)Mg and its corresponding deformation parameterβ_(2) are studied with proton inelastic scattering at 190 MeV/nucleon using in-beamγtechnology with a thick target.Angular distributions of the inelastic scattering cross sections are analyzed with coupled-channel calculations.The deformation parameterβ_(2)=0.41(3)obtained in this work agrees with the earlier experimental results obtained at lower beam energies.Our work demonstrates that the structure of unstable nuclei can be studied with proton inelastic scattering at high incident energies in the vicinity of 200 MeV/nucleon using thick targets.

关键词： beam excited incident

Visible Light Emission in Highly Charged Kr^(17+) Ions Colliding with an Al Surface

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Chinese Physics Letters 2013年第1期30卷 61-62页

作者：杨治虎徐秋梅郭义盼武晔虹宋张勇 Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000 Graduate University of Chinese Academy of Sciences Beijing 100049

We report light emission during the bombardment of Kr^(17+) ions on an Al surface in the wavelength range 300–700 nm.The three spectral lines of the sputtered Al atoms belong to transitions of Al I–at 309.26,Al I–4s 2S1/2 at 394.72 and Al I 3p^(2)P°_(3/2)–4_(s)^(2)S_(1/2) at 396.50 nm.During the neutralization process,the seven spectral lines of Kr I and Kr II from the incident ion of Kr^(17+)attribute to transitions of Kr I 5p^(2)[3/2]2–7d^(2)[1/2]°1 at 616.33,Kr II 5s ^(2)D_(5/2)–5p ^(2)D°_(3/2) at 410.86,Kr II 5p 4P°_(5/2)–6s 4P_(5/2) at 430.58,Kr II 4d^(2)D_(3/2)–4f ^(2)[3]°_(5/2) at 434.42,Kr II 4d ^(4)D_(1/2)–5p ^(2)S°_(1/2) at 485.80,Kr II 4p ^(4)S_(3/2)–6s ^(4)P°_(3/2) at 618.57 and Kr II 5p 4P°_(3/2)–4d ^(2)D_(5/2) at 656.41 nm.Light emissions of sputtered species depend on energy of the incident ions deposited on the target surface atoms.Light emissions of the neutralized projectiles are formed due to many electrons of the conduction band of the solid surface captured in excited states of the incident ion.

关键词： incident transitions

Plasmonic bound states in the continuum for unpolarized weak spatially coherent light

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Photonics Research 2023年第2期11卷 260-269页

作者： ZHUO WANG YAO LIANG JIAQI QU MU KU CHEN MINGJIE CUI ZHI CHENG JINGCHENG ZHANG JIN YAO SHUFAN CHEN DIN PING TSAI CHANGYUAN YU Photonics Research Institute Department of Electrical EngineeringThe Hong Kong Polytechnic UniversityKowloonHong KongChina Department of Electrical Engineering Centre for BiosystemsNeuroscienceand NanotechnologyCity University of Hong KongKowloonHong KongChina State Key Laboratory of Terahertz and Millimeter Waves City University of Hong KongKowloonHong KongChina Photonics Research Institute Department of Electronic and Information EngineeringThe Hong Kong Polytechnic UniversityKowloonHong KongChina

Plasmonic resonances empowered by bound states in the continuum(BICs) offer unprecedented opportunities to tailor light–matter interaction. However, excitation of high quality-factor(Q-factor) quasi-BICs is often limited to collimated light at specific polarization and incident directions, rendering challenges for unpolarized focused light. The major hurdle is the lack of robustness against weak spatial coherence and poor polarization of incident light. Here, addressing this limitation, we demonstrate sharp resonances in symmetric plasmonic metasurfaces by exploiting BICs in the parameter space, offering ultraweak angular dispersion effect and polarization-independent performance. Specifically, a high-Q(≈71) resonance with near-perfect absorption(>90%) is obtained for the input of unpolarized focused light covering wide incident angles(from 0° to 30°). Also, giant electric and magnetic field enhancement simultaneously occurs in quasi-BICs. These results provide a way to achieve efficient near-field enhancement using focused light produced by high numerical aperture objectives.

关键词： polarized incident continuum

Statistical Research on S-Wave incident Angle

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Earthquake Research in China 1994年第1期8卷 124-134页

作者： Jin Xing and Liao ZhenpengInstitute of Engineering Mechanics,SSB,Harbin,Heilongjiang 150080,China

In this paper,the following assumptions are made:1) seismic source is a point one;2) the near-fieid.seismic waves are body ones:3) the medium of the earth is a half-space which is homogeneous and elastic.Yccording to the above-mentioned assumptions,this paper obtains a theoretical formula to estimate S-wave incident angle by using the record of strong ground motion.During the process of calculations,the paper also presents a method of getting in-plane and inti-plane motions from the record of strong ground motion.By making use of 214 records of strong ground motion in the western America,this paper gives a statistical relation among S-wave incident angle,epicentral distance and frequency.The results show that the average value of S-wave incident angle is about 57,and has little to do with the epicentral distance.

关键词： record incident assumptions Angle getting coordinates magnitude deviation extreme mentioned