bluuebunny/crossref_metadata_2025 huggingface dataset:
Gain-guided solitons in positive dispersion lasers
Authors: Lin Hong-Huan  , Lu Zhen-Hua  , Wang Jian-Jun  , Zhang Ying  , Wang Feng-Rui  , Xu Dang-Peng  , Zhang Rui  , Li Ming-Zhong  , Deng Qing-Hua  , Luo Yi-Ming  , Tang Jun  , Ding Lei  ,   中国工程物理研究院激光聚变研究中心，绵阳  621900
Published: December 2020

We numerically simulated the dymamics of mode locking in pure positive dipersion lasers by NLS. Different from soliton lasers operating in net negative dispersion regime or dispersion mananged soliton and similariton lasers operationg in net positive dispersion regime with disperion compensation components, gain saturation and narrowing plays an important role in pulse formation in lasers composed of pure positive dispersion medium, in which the pulses evolve to gain-guided solitons. Stable gain-guided soliton was obtain in two kinds of mode locked fiber lasers operating in the positive dipersion regime, and experimental results confirmed the numerical simulation.
High birefringence tunable effect of microstructured polymer optical fiber
Authors: Zhang Ya-Ni  ,   宝鸡文理学院物理系，宝鸡  721007
Published: December 2020

A new type of microstructured optical fiber with a high birefringence tunable effect is designed by introducing two large air holes in a core region to induce local birefringence and reducing the hole lattices in the x-direction to induce global birefringence. Polarization properties and modal field characteristics of this fiber based on polymethyl methacrylate materials are investigated by using the full vectorial plane wave method. The results show that the fundamental mode birefringence has two maxima in an optical communication wavelength band, and the magnitude and position of the maximum birefringence can be adjusted by changing the wavelength and the structure parameter of this fiber. By adjusting the air holes diameter and hole lattices in the x-direction , the simulation results show the optimized design parameters of this fiber with high birefringence and zero polarization mode dispersion.
Complex acoustic intensity of normal modes in Pekeris waveguide and its application
Authors: Yu Yun  , Hui Jun-Ying  , Zhao An-Bang  , Sun Guo-Cang  , Teng Chao  ,   哈尔滨工程大学水声工程学院，哈尔滨  150001
Published: December 2020

The vector field of normal modes in Pekeris waveguide is studied，and the expression of horizontal and vertical complex acoustic intensity are proposed，especially their characteristics are analyzed in this paper. For the single order mode，the form in the horizontal direction is traveling wave，the corresponding complex acoustic intensity is active，and the vertical form is standing wave，the corresponding complex acoustic intensity is reactive. But for the multi-order mode，either the horizontal or vertical complex acoustic intensity has both active and reactive component because of the interference between the normal modes. Only the active component can transport energy，but the reactive component also carries important information of sound field. The numerical analysis shows that，for the very low frequency sound field of point source，the sign of the active component of horizontal complex acoustic intensity and the reactive component of vertical complex acoustic intensity changed regularly with the change of the depth of acoustic source，so the target depths can be classified by comparing with a critical depth when the receiving transducer is placed in appropriate depths，especially the active component of horizontal complex acoustic intensity，can be used to tell whether the sound source is near the surface or underwater. Further more，the phase angle of complex acoustic intensity is discussed and its distribution regularities are analyzed.
Fabrication of high voltage thyristor based on silicon organic compounds and metal oxides type isolation protective material
Authors: Liu Xiu-Xi  , Wang Gong-Tang  ,   山东师范大学物理与电子科学学院,济南  250014
Published: December 2020

In this paper, we present some experimental results of the KP 500 thyristor which are fabricated by using silicon organic compounds and metal oxides type isolation material. Investigation on the principles of quality control of the semiconductor devices is also reported. The technique was based on coating the device surfaces with the mixture of high purity silicon organic compounds and metal oxides at a proper mixing ratio to protect the semiconductor p-n junction surface aswell as to control the characteristic properties. At room temperature, the resistivity of the solid isolation protective material ρ>7.5×1015Ω·cm, its dielectric constant is equal to 4.7, and the breakdown voltage V>16kV/mm. We demonstrated the advantages of using this material on KP500 thyristor by significantly improving its surface properties, reducing the leakage current and increasing its voltage breakdown level.
Structural evolution and grain growth kinetics of the mechanically alloyed Fe42.5Al42.5Ti5B10 induced by annealing
Authors: Ren Rong  , Wu Yu-Cheng  , Tang Wen-Ming  , Wang Feng-Tao  , Zheng Zhi-Xiang  ,   合肥工业大学材料科学与工程学院，合肥  230009
Published: December 2020

The XRD and TEM techniques were used to study the structural evolution in the mechanical alloying and annealing of Fe42.5Al42.5Ti5B10. The mechanical alloying mechanism during ball milling and the grain growth mechanism during annealing of the powder are also discussed. The results show that the diffusion of Al，Ti and B atoms into Fe lattice occurs during milling，leading to the formation of Fe(Al，Ti，B) solid solution. The process is controlled by continuous diffusion mixing mechanism. The alloying reaction is completed after 50h and the final product is a powder composed of nanocrystalline Fe(Al，Ti，B). Besides the relaxation of crystal defaults and lattice stress，the decomposition of Fe(Al，Ti，B) occurs to form FeAl and TiB2 during heat treatment of the 50h milled powder. The activation energy for the nanocrystalline FeAl growth was calculated to be 525.6kJ/mol according to kinetics theory of nanocrystalline growth.
Formation mechanisms of small fragment ions in nanosecond laser induced fragmentation of C60
Authors: Qian Dong-Bin  , Ma Xin-Wen  , Zhang Da-Cheng  , Zu Kai-Ling  , Liu Hui-Ping  , Wen Wei-Qiang  ,   (1)中国科学院近代物理研究所，兰州  730000; (2)中国科学院近代物理研究所，兰州  730000；中国科学院研究生院，北京  100049
Published: December 2020

The time of flight mass spectrometric technique was used to determine the initial mean kinetic energy of small fragment ions C+n (n≤11) produced from C60 excited by 532nm nanosecond laser pulses. The measured kinetic energy shows little variation with the fragment mass and the laser fluence in a broad range. Based on the assumption that C+30 is produced predominantly by a single electron emission followed by successive C2 evaporation from hot C60 in the nanosecond laser field，the formation of small fragments is interpreted as the complete breakup of the unstable C+30 cage structure. The interpretation is consistent with the previously observed results.
Influence of doping level on electrical properties of ZnO-based composite varistor
Authors: Fu Xiu-Li  , Tang Wei-Hua  , Peng Zhi-Jian  ,   (1)北京邮电大学理学院，北京  100876; (2)浙江理工大学光电材料与器件中心，杭州  310018; (3)中国地质大学(北京)工程技术学院，北京  100083
Published: December 2020

ZnO-based varistors with different doping levels of antimony and bismuth are prepared and their electrical properties are measured. It is found that when the doping level of Sb is small，with the amount of Sb2O3 increasing，the leakage current changes little，both nonlinear coefficient αL and breakdown nonlinear coefficient αB decrease but both field strength EL and breakdown field strength EB increase; when the doping level of Sb is high，with more Sb2O3 added，the leakage current increases sharply，αL and αB decrease further，and EL and EB drop down suddenly. With doping level of Bi increasing，the leakage current increases，αL and αB increase，but EL and EB decrease.
Study of GaN/SiC contact using slow positron beam
Authors: Wang Hai-Yun  , Weng Hui-Min  , Ling C. C.  ,   (1)南京邮电大学应用物理系,  南京  210003; (2)香港大学物理系,香港  中国; (3)中国科学技术大学近代物理系,合肥  230026
Published: December 2020

Using a slow positron beam and the program VEPFIT, we found there exists a barrier in the interface between GaN and SiC, which is caused by lots of band-like defects existing in it. The existence of the barrier induced two backing electric fields in diverse directions close to the interface. These fields can produce a longer diffusion length in the SiC region where no field exists compared with that of SiC region, which has an electric field at a set value. The fitted value of the electric field offers a good reference for studying the situation in a real the interface.
Study on the optical property of quartz glass and Al film reflector under charged particles irradiation
Authors: Zhou Zhong-Xiang  , Wang Hong-Li  , Shen Yan-Qing  , Liu Da-Jun  , Liu Hai  , He Shi-Yu  , Yang De-Zhuang  ,   (1)哈尔滨工业大学空间材料与环境工程实验室，哈尔滨  150001; (2)哈尔滨工业大学物理系，哈尔滨  150001
Published: December 2020

The damage model and the rate equation of quartz glass were set up under charged particles irradiation, and the concentration of ions and electrons produced by ionization were also given. The mathematical fitted results of the change in optical density are in accordance with the experimental results. The model was also applied to optical Al film reflector, and the mathematical fitted results of the integral reflectance of Al film reflector were given. The proposed damage model can be used to describe quantitatively the change in optical property of quartz glass with increasing absorption dose under charged particles irradiation.
X-ray diffraction and phase transition analysis for (K, Na)NbO3-based lead-free piezoelectric ceramics
Authors: Ming Bao-Quan  , Wang Jin-Feng  , Zang Guo-Zhong  , Wang Chun-Ming  , Gai Zhi-Gang  , Du Juan  , Zheng Li-Mei  ,   (1)聊城大学材料科学与工程学院,聊城  252059; (2)山东大学物理学院,济南  250100
Published: December 2020

Characteristic of the orthorhombic and tetragonal phase of (K, Na)NbO3-based lead-free piezoelectric ceramics was analyzed in theory. X-ray diffraction differences between the orthorhombic and tetragonal phase were clarified in the 2θ range from 20° to 60°. For the orthorhombic (K, Na)NbO3-based piezoelectric ceramics, the number and relative intensity of X-ray diffraction peaks were calculated from a monoclinic primitive cell. A method distinguishing orthorhombic and tetragonal phase from the X-ray diffraction patterns was proposed. It is found that the phases of (K, Na)NbO3-based piezoelectric ceramics can be distingwished exactly from peaks of the primitive cell planes (1 0 2) and (1 2 1). For the powder diffraction, the phases can be distinguished more easily by relative intensities of the diffraction peaks for the peak-split position at around 22° or 45°.
Effects of WO3 on optical properties of Er3+-doped tungsten-tellurite glasses
Authors: Jia Xiang-Hua  , Lü Shu-Chen  , Sun Jiang-Ting  , Peng Hong-Yan  , Zhang Mei-Heng  ,   (1)哈尔滨师范大学物理系,哈尔滨  150080; (2)牡丹江师范学院物理系,牡丹江  157012
Published: December 2020

Tungsten-tellurite glasses with the molar compositions of (60+x)TeO2-(30-x)WO3-8BaO-2Na2O-0.5Er2O3 (x=0,5,10,15,20) have been prepared. Effects of WO3 on optical properties of Er3+-doped tungsten-tellurite glasses have been discussed. Along with the WO3 content increasing, Ω2 and Ω6 first increase and then decrease, and the stimulated emission cross-section also behaves in like manner, while Ω4 changes contrarily. According to the McCumber theory, the maximum peak of σe is calculate to be 1.00×10-21cm2 at 1.55μm. The maximum FWHM of Er3+ 4I13/2→4I15/2 emission spectrum is 82nm. In addition, the intensity of upconversion luminescence of the Er3+-doped tungsten-tellurite glasses decreases rapidly with the increasing of WO3 content.
Fabrication, microstructure and UPS spectra of Co: BaTiO3/Si(100) nano-composite films
Authors: Wu Wei-Dong  , He Ying-Jie  , Wang Feng  , Zhan Yong-Jun  , Bai Li  , Ju Xin  , Chen Zheng-Hao  , Tang Yong-Jian  , Sun Wei-Guo  , Pan Hai-Bin  ,   (1)南京大学物理系，南京  210093; (2)四川大学原子与分子物理研究所,成都  610064; (3)四川大学原子与分子物理研究所,成都  610064；中国工程物理研究院激光聚变研究中心,绵阳  621900; (4)中国工程物理研究院激光聚变研究中心,绵阳  621900; (5)中国工程物理研究院激光聚变研究中心,绵阳  621900；西华师范大学物理与电子信息学院,南充  637002; (6)中国工程物理研究院激光聚变研究中心,绵阳  621900；中国科学院物理研究所,北京  100080; (7)中国科学技术大学国家同步辐射实验室,合肥  230029
Published: December 2020

Co: BaTiO3 nano-composite films were successfully fabricated by pulsed laser deposition on single crystal Si(100) surface. The micro-structure of the Co: BaTiO3 nano-composite films with about 30 nm and 100 nm thicknesses were studied by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The Co: BaTiO3 nano-composition films with the above thicknesses were unidirectionally prefer-oriented and polycrystalline, respectively. The atomic force microscopic (AFM) analysis indicated that there were tetragonal crystal grains in the films of about 30 nm thickness. The valence band of the films were investigated by ultraviolet photoelectron spectroscopy (UPS) in detail. The UPS spectra showed that density of electronic states (DOS) of the films with high concentration of Co grains were obviously different from that of bulk BaTiO3 single crystal.
Research on the high-rate deposition of μc-Si:H by VHF-PECVD
Authors: Guo Xue-Jun  , Lu Jing-Xiao  , Chen Yong-Sheng  , Zhang Qing-Feng  , Wen Shu-Tang  , Zheng Wen  , Shen Chen-Hai  , Chen Qing-Dong  ,   郑州大学材料物理教育部重点实验室,郑州  450052
Published: December 2020

The μc-Si:H films were deposited by VHF-PECVD, the effects of silane concentration, power density, deposition pressure and total flow rate on the deposition rate and crystallization of μc-Si:H were extensively studied. Phase diagram in the plot of deposition pressure against power was determined. The deposition rate of μc-Si:H has reached 0.75nm/s. Incorporating such μc-Si:H films as i-layer, the single-junction solar cell on glass substrate showed an conversion efficiency of 5.5%.
Hyperspectral imaging differential optical absorption spectroscopy
Authors: Si Fu-Qi  , Xie Pin-Hua  , Klaus-Peter Heue  , Liu-Cheng  , Peng Fu-Min  , Liu Wen-Qing  ,   (1)环境物理研究所，德国海德堡大学，海德堡，德国; (2)卫星研究小组，马普化学所，美因茨，德国; (3)中国科学院环境光学与技术重点实验室，中国科学院安徽光学精密机械研究所，合肥  230031
Published: December 2020

The technique of passive differential optical absorption spectroscopy (DOAS) is based on fingerprint absorption of probed gas species, which enables simultaneous monitoring of a variety of pollutants found in the atmosphere using scattering light as light source. We describe an optical remote-sensing instrument which is based on imaging spectrometer that permits spatially resolved mapping of atmospheric trace gases by passive DOAS method. The applications of one spatial dimensional measurement of gas cell and imaging of the nitrogen dioxide over city main road were also reported in this paper. With scattered sunlight as the light source, the system based on imaging spectrometer simultaneously acquiring spectral information in one spatial dimension, the second spatial dimension is scanned by a moving mirror.
Backscattered Mueller matrix patterns of optically active media and its application in noninvasive glucose monitoring
Authors: Xu Lan-Qing  , Li Hui  , Xie Shu-Sen  ,   福建师范大学医学光电科学与技术教育部重点实验室，福州  350007
Published: December 2020

In this paper Stokes/Mueller formula was used to trace the polarization state of photon packet. Single scattering model and Monte Carlo method were used to investigate the influence of glucose on polarized light in turbid media. Some Mueller matrix elements show optical rotation in the presence of glucose. Using image subtraction and integration, an approximately linear relationship between low glucose concentration in the physiological range and optical rotation degree was found.
Effect of atmospheric turbulence on the spatial coherence of quasi-monochromatic Gaussian Schell-model beams propagating in the slant path
Authors: Wang Hua  , Wang Xiang-Zhao  , Zeng Ai-Jun  , Yang Kun  ,   (1)中国科学院上海光学精密机械研究所,上海  201800; (2)中国科学院上海光学精密机械研究所,上海  201800;中国科学院研究生院,北京  100049
Published: December 2020

By using the mutual coherence function of quasi-monochromatic Gaussian Schell-model (GSM) beams propagating in a slant path through the turbulent atmosphere, the complex degree of coherence of those beams is derived analytically. By employing the lateral coherence length (that can be derived from the complex degree of coherence ) of quasi-monochromatic GSM beams to characterize their spatial coherence, the effect of atmospheric turbulence on the spatial coherence of the beams was studied. The result shows that：(1) When θ≤88°, the lateral coherence length increases firstly and then keeps unchanged as the beam propagates in the turbulent atmosphere. (2) When θ≥89°, the lateral coherence length increases firstly and then reaches a maximum value after the beam propagates acertain distance in the turbulent atmosphere, then begins degrading and keeps decreasing with increasing distance. (3) Three beams with different lateral coherence lengths at the source plane (z=0) will have almost the same lateral coherence length after they propagate a certain distance in the turbulent atmosphere. Lastly, a physical explanation was given to the results.
Experimental and numerical investigations on the electro-magnetic control of hydrofoil wake
Authors: Chen Yao-Hui  , Fan Bao-Chun  , Chen Zhi-Hua  , Zhou Ben-Mou  ,   南京理工大学瞬态物理实验室，南京  210094
Published: December 2020

The Lorentz force generated in the low-conduction fluid can be used to control the boundary layer effectively. In the present paper, experimental and numerical investigations have been performed to suppress the flow separation of a hydrofoil with a certain attack angle in the low-conduction fluid. Both experimental and numerical results show that the Lorentz force parallel to the moving fluid can suppress the flow separation and thus remove the von Karman street. However, when Lorentz forces are applied opposite to the moving fluid of the surface of the foil, the separation point cannot be suppressed, instead, it would move reversely to the leading edge and the vortex street of the downstream acts as in the cases with a large attack angle.
Analysis of differential-phase-shift keying protocol for a two-way quantum-key-distribution system
Authors: Jiao Rong-Zhen  , Feng Chen-Xu  ,   北京邮电大学理学院，北京  100876
Published: December 2020

The performance of a two-way quantum-key-distribution (QKD) system are analyzed using the differential-phase-shift keying (DPSK) protocol. The comparison is based on the secure communication rate as a function of distance for three QKD protocols: the Bennett-Brassard 1984, the Bennett-Brassard-Mermin 1992, and the coherent differential-phase-shift keying protocols. We discussed the security of DPSK protocol against any type of individual photon splitting attack and concluded that the simple and efficient DPSK protocol allows for more than 200km of secure communication distance with high communication rates.
Approach of continuous time random walk model to anomalous diffusion
Authors: Lin Fang  , Bao Jing-Dong  ,   北京师范大学物理系，北京  100875
Published: December 2020

A numerical method based on the continuous time random walk (CTRW) theory is developed to study the normal diffusion and anomalous diffusion including both sub-diffusion and super-diffusion. The probability density functions for both the jump distance and the residence time in the CTRW model are determined as well as the Metropolis sampling method in the periodic potential has been improved. The directional transport of a Brownian motor in both a flashing ratchet potential and a rocking ratchet potential is investigated. Our results have shown that the maximum of directional current occurs in the case of super-diffusion in a flashing ratchet and in the case of ballistic diffusion in a rocking ratchet.
T-S fuzzy system design by chaotic ant swarm algorithm
Authors: Li Li-Xiang  , Peng Hai-Peng  , Yang Yi-Xian  ,   北京邮电大学信息安全中心，网络与交换技术国家重点实验室，北京  100876
Published: December 2020

essful application of the algorithm to the problem of designing fuzzy system that matches the desired input-output pairs. The resulting CAS-designed fuzzy systems models can be used to achieve the identification and adaptive control of dynamical systems. Simulation results show that the proposed method is effective.
Division time chaos switch-synchronization for a class interrelated chaotic systems
Authors: Liu Yang-Zheng  , Jiang Chang-Sheng  , Lin Chang-Sheng  ,   (1)南京工程学院非线性物理研究所,南京  211167; (2)南京航空航天大学自动化学院,南京  210016; (3)南京航空航天大学自动化学院,南京  210016；南京工程学院非线性物理研究所,南京  211167
Published: December 2020

The method of division time chaos switch-synchronization for a class of interrelated chaotic systems is proposed. The division time chaos switch-synchronization between each chaotic subsystem and its duplicate system is achieved via linear feedback control. Based on the theory of stability of time-varying systems, the range of feedback gain for synchronization of these interrelated chaotic systems is derived. Numerical simulation shows the effectiveness and feasibility of the method.
Linear and nonlinear generalized synchronization of autonomous chaotic systems
Authors: Wang Xing-Yuan  , Meng Juan  ,   大连理工大学电子与信息工程学院，大连  116024
Published: December 2020

The generalized synchronization of autonomous chaotic systems is investigated. A new approach is proposed based on the modified state observer method and the pole placement technique, which have a wide scope of applications. The linear and nonlinear generalized synchronizations of autonomous chaotic systems are achieved by using the proposed method. According to the state observer theory, some sufficient conditions of global asymptotic generalized synchronization between the drive and response systems are obtained. Numerical simulations further illustrate the effectiveness of the proposed scheme.
Chaotic control of the coupled Logistic map
Authors: Wang Xing-Yuan  , Wang Ming-Jun  ,   大连理工大学电子与信息工程学院，大连  116024
Published: December 2020

Based on the stability criterion of discrete systems, state feedback is used to stabilize unstable low-periodic orbits of the coupled Logistic map, and a new scheme is proposed to change the parameter value of the first bifurcation point of this dynamic system optionally. Numerical simulations show the effectiveness of our methods.
Synchronization of Julia sets of complex systems
Authors: Liu Shu-Tang  , Zhang Yong-Ping  ,   山东大学控制科学与工程学院，济南  250061
Published: December 2020

Julia set, being a fractal set in the literature of nonlinear physics, has significance for the engineering applications. In this work, we are the first to define the synchronization of Julia sets between different systems and introduce a nonlinear coupling method to realize the synchronization of Julia sets of the same systems but with different parameters. We also illustrate the effectiveness of our method by the synchronization of Julia sets of polynomial and trigonometric functions respectively.
Fitz hugh-nagumo neural system driven by colored noises
Authors: Wang Chao-Qing  , Xu Wei  , Zhang Na-Min  , Li Hai-Quan  ,   西北工业大学应用数学系，西安  710072
Published: December 2020

We investigated the phase transition and the mean first-passage time of a Fitz hugh-nagumo neural system driven by colored noises, and the expressions of the stationary probability distribution and the mean first-passage time were obtained. The conclusions show that the parameters α,τ and β can induce phase transition, and there is a locking phenomenon in the system. Each parameter affects the system's mean first-passage time quite differently.
Impact of edges for new nodes on scale-free networks
Authors: Guo Jin-Li  ,   上海理工大学管理学院，上海  200093
Published: December 2020

This paper analyses the impact of edges for new nodes on scale-free networks. Although non-stationary average degree distribution of a sub-linearly growing network follows the power law, the stationary average degree distribution of the network does not. This paper proposes a random growth model whose node arrival process is a renewal process and the number of new edges is a random variable with binomial distribution. The result shows that the stationary average degree distribution of the model follows the power law under an appropriate condition, and the condition is found.
The characteristics of terahertz radiation from InAs irradiated with femtosecond optical pulses of different wavelengths
Authors: Sun Hong-Qi  , Zhao Guo-Zhong  , Zhang Cun-Lin  , Yang Guo-Zhen  ,   首都师范大学物理系，太赫兹波谱与成像重点实验室，北京  100037
Published: December 2020

The characteristics of terahertz (THz) radiation from the surface of an (100)p-InAs crystal excited by fs laser pulses of different wavelengths (from 750 to 850nm) are investigated experimentally. The terahertz radiation can be interpreted as being emited from accelerated photo-carriers in the Dember field and be detected by using the free-space electro-optic sampling method. A (110) ZnTe crystal was used as detector. The results of experiment show that the Dember field in the surface of InAs, concentration of excited carriers, intervalley scattering and the concentration of excited carriers of different states, all changed when the wavelength of excited pulse changed, so the radiant efficiency and the effective spectral width of terahertz wave were different. This investigation will be useful to the measure of time domain spectrum of samples and the optimization of experimental system. It also gives better physieal insight into the ultra-fast process of terahertz wave radiation from InAs excited by femtosecond pulses.
Rovibronic spectrum of N2O+ ion at the A2Σ+ state
Authors: Wang Hua  , Liu Shi-Lin  , Liu Jie  , Wang Feng-Yan  , Jiang Bo  , Yang Xue-Ming  ,   (1)中国科学技术大学化学物理系，合肥微尺度物质科学国家实验室，合肥  230026; (2)中国科学院大连化学物理研究所，分子反应动力学国家重点实验室，大连  116023
Published: December 2020

The rotational structures of the photofragment excitation spectrum of N2O+(A2Σ+) at high vibrational levels have been studied experimentally. The parent N2O+(X2Π) ions were prepared by (3+1) resonance-enhanced multiphoton ionization of jet-cooled N2O molecules by 36055nm laser beam，and were excited by another laser to the predissociative A2Σ+ state in the range of 280—320nm. Two types of rotational transition，i.e.，2Σ+←2Π and 2Π←2Π，have been clearly observed for a series of vibronic transitions. The rotational constants and spin splitting constants have been obtained from the spectral analysis.
Novel miniaturized planar left-handed metamaterial transmission lines verified by the backward wave property
Authors: Wu Ming-Feng  , Meng Fan-Yi  , Fu Jia-Hui  , Wu Qun  , Wu Jian  ,   (1)哈尔滨工业大学电子与信息技术研究院，哈尔滨  150001; (2)哈尔滨工业大学电子与信息技术研究院，哈尔滨  150001；电波环境特性及模化技术国防科技重点实验室，北京  102206
Published: December 2020

Based on the technique of reducing working frequency of split ring resonators (SRR)，this paper presents a miniaturized left-handed metamaterial transmission line unit，and retrieves the effective permittivity and permeability parameters from the transmission and reflection data. To verify the presence of the left-handed frequency band，3D numerical simulation is conducted to an array of left-handed metamaterials including eight units，which demonstrates that the left-handed metamaterial microstrip line can support unique backward wave property very well. Compared with conventional left-handed microstrip lines，this structure has been reduced by 60% in electrical sizes，and would be more convenient for fabrication in applications as miniaturized planar circuit components.
Design of reflection resonant grating filters
Authors: Ma Jian-Yong  , Liu Shi-Jie  , Wei Chao-Yang  , Xu Cheng  , Jin Yun-Xia  , Zhao Yuan-An  , Shao Jian-Da  , Fan Zheng-Xiu  ,   (1)中国科学院上海光学精密机械研究所，上海  201800; (2)中国科学院上海光学精密机械研究所，上海  201800；中国科学院研究生院，北京  100039
Published: December 2020

Resonant grating filters based on grating abnormality have attracted much attention in recent years owing to their high peak reflectivity，low sideband reflection and controllable line width of central wavelength. Some special characteristics which are hard to be achieved by multilayer stack alternated with high and low refractive indices can be realized with guide-mode resonance of sub-wavelength gratings whose line width of central wavelength can be compressed to less than one nanometer under the condition of weak modulation of gratings. However，the sideband reflections near or far from the central wavelength are still somewhat high due to Fresnel reflection between air and material. According to the effective medium theory (EMT)，sub-wavelength waveguide gratings can be viewed as thin films. In this paper，the sideband reflections of resonant grating filters are effectively reduced through antireflection design based on thin film theory and narrow band resonant filters are attained in the range of visible wavelength with good characteristics.
A hybrid analytical-numerical algorithm for scattering from a 3-D target above a randomly rough surface
Authors: Ye Hong-Xia  , Jin Ya-Qiu  ,   复旦大学波散射与遥感信息国家教育部重点实验室，上海  200433
Published: December 2020

This paper presents a hybrid iterative algorithm of analytic KA-numerical MOM for scattering computation from a 3-dimensional (3-D) perfect conducting target above a randomly rough surface. The coupled integral equations (IEs) are derived for difference scattering computation. The method of moment (MoM) with the conjugate gradient (CG) approach is used to solve the target's IE，and the Kirchhoff approximation (KA) is applied to scattering from the rough surface. The coupling iteration takes account of the interactions between the target and the underlying rough surface. The convergence of this hybrid algorithm of KA-MoM is numerically validated. Since there is only one numerical integral along the rough surface performed for KA computation，memory and CPU time are significantly reduced. Numerical results of bistatic scattering from a PEC ellipsoid or cubic target above a Gaussian rough surface produced by Monte Carlo method are obtained.
Experimental study of the generation of Laguerre-Gaussian beam using a computer-generated amplitude grating
Authors: Li Feng  , Gao Chun-Qing  , Liu Yi-Dong  , Gao Ming-Wei  ,   北京理工大学信息科学技术学院光电工程系，北京  100081
Published: December 2020

Laguerre-Gaussian (LG) beams attratts much attention in the fields of rotating micro-particle manipulation and information processing due to their special phase structures and related orbital angular momentum. In this paper the generation of LG beam by an amplitude grating was theoretically studied and the LG beams with azimuthal number of ±1 were obtained by the amplitude grating produced by the computer-generated hologram (CGH). Influences of main factors on the beam transformation were discussed.
Entanglement transfer via cross-Kerr nonlinearity
Authors: Yang Jian  , Ren Min  , Yu Ya-Fei  , Zhang Zhi-Ming  , Liu Song-Hao  ,   (1)广州大学工程抗震中心，广州  510405; (2)华南师范大学信息光电子科技学院，广东省光子信息技术重点实验室，广州  510006
Published: December 2020

We propose a scheme for realizing entanglement transfer based on the cross-Kerr nonlinear interaction between field-modes. By using this scheme the entanglement can be transferred from the field-states with discrete variables to the field-states with continuous variables. By suitably choosing the amplitude of the initial coherent states，we can obtain the maximum entangled coherent states.
Ultrabroadband continuum spectrum generated in Ar gas
Authors: Zhang Li-Ping  , Li Hai-Ning  , Wu Hong  , Li Xian  , Ding Liang-En  ,   精密光谱科学与技术国家重点实验室，华东师范大学物理系，上海  200062
Published: December 2020

We observed the supercontinuum in Ar during the propagation of a femtosecond pulse with wavelength of 800nm，repetition rate of 10Hz and pulse duration of 30fs. We studied the supercontinuum when changing the chirp of the pulse，pulse energy，pressure in the cell and the focal length to find the optimal conditions. And we observed the steady broadest supercontinuum extending up to 200nm with the pulse of 20mJ energe，29×104fs2 chirps when the focal length was 500mm and the pressure of the cell was 23×105Pa. We measured the far-field pattern of the continuum and found the divergence angle of the white light to be 31mrad.
Experimental research of supercontinuum generation by femtosecond pulse in highly nonlinear photonic crystal fiber
Authors: Liu Wei-Hua  , Song Xiao-Zhong  , Wang Yi-Shan  , Liu Hong-Jun  , Zhao Wei  , Liu Xue-Ming  , Peng Qin-Jun  , Xu Zu-Yan  ,   (1)武汉工业学院数理科学系，武汉  430023；中国科学院西安光学精密机械研究所瞬态光学与光子技术国家重点实验室，西安  710119; (2)中国科学院物理研究所光物理实验室，北京  100080; (3)中国科学院西安光学精密机械研究所瞬态光学与光子技术国家重点实验室，西安  710119
Published: December 2020

We pumped a 1m long highly nonlinear photonic crystal fiber by a Ti: sapphire laser and generated a supercontinuum with the wavelength extension form 420—1700nm，of which the output power was about 170mW and we conversion efficiency was above 20%. The experiment result was particularly analyzed and compared with calculated result，and we consider the main reasons of supercontinuum generation was fission of high-order solitons and four-wave mixing. We also researched the supercontinuum generation under different pump power and wavelength conditions. With the pump power increased gradually in the same fiber，the output spectrum can be divided into initial broadening stage，dramatic broadening stage and saturation broadening stage. When the output spectrum is in the initial broadening stage or saturation broadening stage，there exists some residual pump，when the output spectrum is in the dramatic broadening stage，the highest conversion efficiency is obtained. When the pump wavelength is in the anomalous dispersion reion of the fiber，the spectrum width is far broader than that in the zero dispersion region，but the shapes of the spectra are very similar. These conclusions provide valuable reference for supercontinuum system optimization and control.
Kerr-type spatial optical solitons in planar waveguides with finite width and the design of all optical devices
Authors: Xiao Yi  , Guo Qi  ,   (1)华南师范大学光子信息技术广东省高校重点实验室，广州  510631; (2)华南师范大学光子信息技术广东省高校重点实验室，广州  510631；暨南大学光电工程系，广州  510632
Published: December 2020

The propagation of paraxial light beams injected at an inclined angle in a planar waveguide with finite width is studied by numerical method. The soliton beams with different wavelength and same width，if their incident point and incident slanting angle are the same，will propagate along the same periodic Z-type route in the planar waveguide. With the power of the beam increasing，the distance between two adjacent reflecting points will become longer and longer with the propagation distance and the Z-type route will lose its periodicity. When the power of a beam become fairly strong，the beam will propagate along z direction of the waveguide，and will no longer be reflected back and forth between the two boundaries of the planar waveguide. Using the characteristic that a beam injected at an inclined angle in the waveguide will propagate along different route with different power，a power switch and an optical time division demultiplexer are designed.
The thick ring resonators to achieve negative permeability and its left-handed behavior in perpendicular propagation
Authors: Liu Ya-Hong  , Song Juan  , Luo Chun-Rong  , Fu Quan-Hong  , Zhao Xiao-Peng  ,   西北工业大学电流变技术研究所，西安  710072
Published: December 2020

We experimentally investigated the microwave transmittance properties of the thick ring resonators in a rectangular waveguide for propagation perpendicular to the plane of the ring resonators. Our ring resonators are different from the conventional split ring resonators which have the certain thickness. It is found that a transmission dip occurs at 145GHz and the transmission phase has a shift at the resonance frequency for the thick ring resonators. Furthermore，we calculated the permeability of the thick ring resonators applying bianisotropic composite modeling and found the negative permeability near the resonance transmission dip. We measured the left-handed peak and phase advance by using the thick ring resonators combined with wires which have transmission pass bandwidth of 15GHz and transmission value of -21dB.
The solvent effects on the complexing reaction of nickel dithiolene and ethylene
Authors: Han Qing-Zhen  , Geng Chun-Yu  , Zhao Yue-Hong  , Qi Chuan-Song  , Wen Hao  ,   (1)北京石油化工学院化学工程系,北京  102617; (2)中国科学院过程工程研究所多相实验室,北京  100080; (3)中国科学院过程工程研究所多相实验室,北京  100080；中国科学院研究生院,北京  100049
Published: December 2020

Theoretical studies of solvent effects on the reaction of complexing ethylene and nickel dithiolene have been carried out by calculating the molecular geometry, electron distribution, and frequency of all the stagnation points existing in the reaction potential profiles by means of density functional theory methods at the B3LYP/6-31G(d) level. On the basis of frequency analysis and statistical thermodynamic theory, some thermodynamic parameters for the titled compound have been obtained for different solvents. It is shown that the bond energy of ethylene and nickel dithiolene enhances with the increase of the solvent polarity. In addition, the frontier orbital energy gaps of the two transition states will increase, while those of the product and the intermediate as well as the corresponding solvation stabilization energy will decrease. Furthermore, these results demonstrate that in polar solvents the reaction of complexing ethylene and nickel dithiolene may become easier and faster to occur and yield a more stable product. Notably, an obvious solvent effect can be observed when the value of the solvent dielectric constant lies between 1.0 and 7.58, while the solvent effect will tend to be maximal when the value of solvent dielectric constant exceeds 7.58.
A proposed high electrical efficiency and high current intensity radial split-cavity oscillator
Authors: Zhang Yun-Jian  , Meng Fan-Bao  , Fan Zhi-Kai  , Luo Xiong  ,   中国工程物理研究院应用电子学研究所,绵阳  621900
Published: December 2020

Using the structure of the coaxial vircator oscillator, a new kind of compact radial split-cavity oscillator is presented. The characteristic of the oscillator is that the input current can be intense, and this is the main reason for the output microwave power to be high. Taking into consideration all kinds of factor, under the condition of the voltage of 410kV and the beam current of 35kA, the numerical simulation gives an average output microwave power of about 50GW at the microwave frequency of 146GHz, and the electronic efficiency is 348%.
Absorption experiments on radiatively heated Al plasma
Authors: Zhang Ji-Yan  , Yang Jia-Min  , Xu Yan  , Yang Guo-Hong  , Yan Jun  , Meng Guang-Wei  , Ding Yao-Nan  , Wang Yan  ,   (1)北京应用物理与计算数学研究所，北京  100088; (2)中国工程物理研究院激光聚变研究中心，绵阳  621900
Published: December 2020

K-shell absorption spectroscopy of radiatively heated Al sample is reported. The experiment was conducted on Shenguang-Ⅱ Laser facility. Eight main beams of the facitliy are injected into a conical gold cavity to produce high-temperature X-ray heating source. This X-ray source is then used to irradiate an Al foil located in the center of the cavity, and heat the foil to temperature of tens of electronvolt. After a time delay, a ninth short-pulsed laser beam is focused on a gold disk to generated an X-ray point-backlighter. By measuring the spectra both directly from backlighter and attenuated by the heated sample in the wavelength range of 075—085nm, the K-shell absorption spectrum of Al is obtained. By fitting the experimental spectrum with theoretical calculation, electron temperature of the heated sample is determined.
The initiation phase of pseudospark discharge in a hollow cathode via PIC/MCC simulation
Authors: Zheng Fei-Teng  , Yang Zhong-Hai  , Jin Xiao-Lin  ,   电子科技大学物理电子学院,成都  610054
Published: December 2020

We have developed a theoretical and computational model to study the initiation phase of pseudospark discharges in a hollow cathode via a quasi-three-dimensional electrostatic particle-in-cell plus Monte Carlo collision(PIC/MCC) method. The numerical results clearly identified different processes of ionization growth. It has been found that the ionization processes are determined by hollow cathode effect and local electric field. The growth is dependent on α ionization multiplication due to local space charge in the stage from initial ionization growth to the onset of the hollow cathode effect, and then the hollow cathode effect becomes the leading factor.
Ultrafast optical Kerr effect in amorphous chalcogenide films
Authors: Liu Qi-Ming  , He Xuan  , Gan Fu-Xi  , Qian Shi-Xiong  ,   (1)复旦大学物理系,上海  200433; (2)武汉理工大学硅酸盐材料工程教育部重点实验室,武汉  430070; (3)中国科学院上海光学精密机械研究所，上海  201800
Published: December 2020

Amorphous chalcogenide As2S3, As2Se3, GeS2, GeSe2, Ge20As25S55, Ge20As25Se55, Ge10As40S20Se30 films were studied by femtosecond OHD-OKE. Ict was indicated that the third-order nonlinear susceptibility χ(3) was as large as 10-12 esu, and they also exhibited a very fast response time shorter than 200 fs. Their nonlinear refractive indices and absorption were also calculated from the above results. The ultrafast response and large third-order nonlinearity in amorphous chalcogenide films are attributed to the ultrafast distortion of the electron cloud of atoms.
Dynamics of acrylamide-based photopolymer holographic gratings
Authors: Chen Ke  , Cheng Jian-Qun  , Xiao Yong  , Tang Dao-Guang  , Huang Ming-Ju  ,   河南大学光学与光电子技术研究所，物理与电子学院，开封  475004
Published: December 2020

The theoretical photochemical and photopolymerization diffusion model and the dynamic parameters of the photopolymer are studied. A new holographic photopolymer which is composed of acrylamide as monomer, ployvinylalcohol as binder, triethanolamine as initiator sensitized by erythrosine B is prepared. By means of fitting the experimental data of transmittance and diffraction efficiency as a function of time, the influence of the molar-absorption coefficient ε, the quantum yield Φ and the photobleaching coefficient k in photochemical dynamics for different concentrations of erythrosine B, and polymerization rate k0, diffusion time constant τD and the maximal refractive index modulation Δn in photopolymerization diffusion dynamics for different exposure intensity, are presented.
Enhancing the emission efficiency in photonic crystal waveguide with coupled waveguide arrays
Authors: Wang Qiong  , Cui Yi-Ping  , Yan Chang-Chun  , Zhang Ling-Ling  , Zhang Jia-Yu  ,   东南大学电子科学与工程学院先进光子学中心，南京  210096
Published: December 2020

We propose a system of enhanced emission efficiency by employing coupled waveguide arrays to a single-mode photonic crystal waveguide. The FDTD simulation results show that, when the coupled waveguide arrays are placed properly at the exit plane of the single-mode photonic crystal waveguide, the output light can be split into many light beams, and the interference of these light beams can produce a focusing emission beam, which greatly enhances the emission efficiency. In addition, when the row number of the waveguide arrays is larger than a certain value (2N=8), the state of the emission is nearly steady and the most compact structure can be obtained. This type of photonic crystal has potential applications in near-field optics or integrated optics.
The light intensity-dependent superprism phenomenon in nonlinear photonic crystals
Authors: Chen Xiao-Jun  , Wu Li-Jun  , Hu Wei  , Lan Sheng  ,   华南师范大学光电子信息实验室广东省高校重点实验室，广州  510006
Published: December 2020

We investigate the light intensity-dependent superprism phenomenon in the two-dimensional Kerr nonlinear photonic crystal (PhC) by nonlinear finite-difference time-domain (FDTD) technique. Results show that when the intensity of the self-pumping beam is increased from 70 to 300 W/μm, the refraction angle of the beam can be tuned about 10 degree. Furthermore, when the input power is high enough, the wave vector can be rotated by the local refractive index interfaces induced by the pumping power. By monitoring the transmission efficiency at different depths in PhCs, the propagating beam is found to undergo several states which correspond to different power loss mechanisms.
A method of color image single-channel encryption
Authors: Gao Li-Juan  , Yang Xiao-Ping  , Li Zhi-Lei  , Wang Xiao-Lei  , Zhai Hong-Chen  , Wang Ming-Wei  ,   (1)南开大学现代光学研究所，教育部光电信息技术科学重点实验室，天津  300071; (2)天津理工大学电子信息与通信工程学院，天津  300191
Published: December 2020

A new method for color image single-channel encryption is proposed. According to tricolor grating theory, a color image is encoded into a gray scale image, and then the gray scale image is encrypted by double-phase encoding. Thus by combining multi-channel with single-channel, only one laser is needed for encryption. With this method, both single-channel encryption and high security are ensured, and the system is simpler and more practical. Computer simulation proves the validity of the proposed method.
Effect of loading-wave-front width on micro-jet from aluminum surface
Authors: Wang Pei  , Shao Jian-Li  , Qin Cheng-Sen  ,   北京应用物理与计算数学研究所，北京  100088
Published: December 2020

With smoothed particle hydrodynamics, we calculate the formation of micro-jet from the groove of metal surface, and reveal the dependence on the width of loading wave front. The calculated results show that, with the decreasing loading speed,both the mass and the front velocity of ejection decrease, and the mass fraction with low velocity increases. We draw the conclusion that the formation of micro-jet is a result of the particles near the groove acquiring axial velocity and impacting at the axis, and the efflux derives from a layer near the groove. The thin layer becomes smaller when widening the wave front, which is because some particles can no longer satisfy the lock condition of jet strength with the decreasing impact velocity and the increasing impact angle, and then can jet no more.
Mamdani-Larsen fuzzy system based on expectation maximization algorithm and its applications to time series prediction
Authors: Zhang Qin-Li  , Wang Shi-Tong  ,   (1)江南大学信息工程学院，无锡  214122; (2)江南大学信息工程学院，无锡  214122；北华航天工业学院,廊坊  065000
Published: December 2020

This work explores how Epanechnikov mixture model can be translated to Mamdani-Larsen fuzzy model. The mathematical equivalence between the conditional mean of an Epanechnikov mixture model and the defuzzified output of a Mamdani-Larsen fuzzy model is proved. The result provides a new perspective of studying the Mamdani-Larsen fuzzy model by interpreting a fuzzy system from a probabilistic viewpoint. Instead of estimating the parameters of the fuzzy rules directly, the parameters of an Epanechnikov mixture model can be firstly estimated using any popular density estimation algorithm, such as expectation maximization. Mamdani-Larsen fuzzy model trained in the new way has higher accuracy and stronger anti-noise capability. After comparing the simulation results with the ones obtained from other fuzzy system modeling tools, it can be claimed that the results are successful.
Defect mode properties of magnetized plasma photonic crystals
Authors: Zhang Hai-Feng  , Ma Li  , Liu Shao-Bin  ,   (1)南昌大学机电学院，南昌  330031;中国人民解放军炮兵学院南京分院，南京  211132; (2)南昌大学理学院，南昌  330031; (3)南京航空航天大学信息科学与技术学院，南京  210016
Published: December 2020

The piecewise linear current density recursive convolution (PLCDRC) finite-difference time-domain (FDTD) method for magnetized plasmas is applied to study the characteristic of one_dimensional magnetized plasma photonic crystals with a defect layer. In frequency domain, the transmission ratio of electromagnetic Gaussian pulses is computed, and the effects of periodic constant, parameters of plasma and parameters of defect layer such as dielectric length and position on defect mode properties of magnetized photonic crystals are analysed. The results show that the frequency of defect mode cannot be tuned by changing the parameters of position and periodic constant, changing the length of the defect layer can increase the number of defect mode, and the frequency and peak of defect mode can be changed by different parameters of plasma.