bluuebunny/crossref_metadata_2025 huggingface dataset:
The generation of high efficiency and high quality andhigh stability parametric amplified light
Authors: Liu Hong-Jun  , Chen Guo-Fu  , Zhao Wei  , Wang Yi-Shan  ,   (1)中国科学院西安光学精密机械研究所瞬态光学技术国家重点实验室，西安 710068; (2)中国科学院西安光学精密机械研究所瞬态光学技术国家重点实验室，西安 710069; (3)中国科学院西安光学精密机械研究所瞬态光学技术国家重点实验室，西安 710070; (4)中国科学院西安光学精密机械研究所瞬态光学技术国家重点实验室，西安 710071
Published: December 2020

The effects of a series of parameters such as injected signal intensity , pump intensity, crystal length have been analyzed in Optical parametric amplification(OPA). The gain saturation and pump depletion were taken into account. The stability of an OPA system was investigated in both the small signal injection and the large signal injection. Experimental investigations of OPA based on two noncollinear phase-matched LBO OPA under the small signal injection and the large signal injection have been carried out，and the experimental data are in agreement with the theoretical results. The theoretical and experimental results all demonstrated that there exists a strong gain saturation region where parametric light with high efficiency and high quality and high stability can be obtained by properly choosing relevant system parameters.
Investigations on beam-current-pulse-shortening in a long pulse relativistic klystron amplifier
Authors: Huang Hua  , Fan Zhi-Kai  , Tan Jie  , Ma Qiao-Sheng  , Gan Yan-Qing  , Chang An-Bi  ,   中国工程物理研究院应用电子学研究所，绵阳 621900
Published: December 2020

This paper presents pulse shortening of electron beams drifting through the input cavity and the idler cavity on an L-band long pulse relativistic klystron amplifier. We investigate one of the main mechanism of beam-current-pulse-shortening in which the interaction of asymmetric modes of cavity and the beams leads to the beams' expansion. Selective damping to suppress the asymmetric modes is described. The problem of beam-current-pulse-shortening through the idler cavity gap is removed to a certain extent after parameter adjustment of the input microwave and the idler cavity. In the experiment, the 446 kV,3.0 kA，1.3 μs hollow electron beams generated about 2.0 kA modulated current after two idler-cavity gaps, the width of electron beams' pulse is increased from 0.3 μs to 1.0 μs.
Dielectric tensor of 2D relativistic motional plasma
Authors: Tang Chang-Jian  , Gong Yu-Bin  , Yang Yu-Zhi  ,   (1)电子科技大学物理电子学院,成都 610054; (2)四川大学物理科学与技术学院,成都 610065
Published: December 2020

The relativistic motional plasma model is proposed ane defined. Using the charge fluid perturbation theory, the two-dimensional (2D) self-disturbance of the system and the phenomenon of beam-wave interaction are suudied. From this, the dielectric tensor of 2D relativistic motional plasma is given. We found that the relativistic motional plasma is an electromagnetic dielectric with a complex dispersion relation, and it displays a non-uniform complex electromagnetic space. In this paper, the response of relativistic motional plasma to the wave frequency is obtained by the numerical computation.
Motion damping in channelling effects and the chaotic behaviour of a system
Authors: Luo Shi-Yu  , Tan Yong-Ming  , Shao Ming-Zhu  , Wei Luo-Xia  , Deng Li-Hu  ,   东莞理工学院，东莞 523106
Published: December 2020

The equation of motion of particles has been reduced to the pendulum equation with a damping term and a forced term by using the sine-squared potential.The global bifurcation and chaotic behaviours have been analysed using Melnikov technique, and it is shown that the enhancement of the radiation background and the random phenomenon of the channelling efect are related to chaotic behaviours of the system.
Photoelectron diffraction study on the polarity of GaN surface
Authors: Xu Peng-Shou  , Deng Rui  , Pan Hai-Bin  , Xu Fa-Qiang  , Xie Chang-Kun  , Li Yong-Hua  , Liu Feng-Qin  , K. Yibulaxin  ,   (1)中国科学技术大学国家同步辐射实验室，合肥 230029; (2)中国科学院高能物理研究所同步辐射中心,北京 100039
Published: December 2020

We have obtained the photoelectron diffraction curves from (1010) and (1120) crystal planes on GaN(0001) surface by using a polar scan mode of x-ray photoelectron diffraction (XPD). On the basis of principle of “forward focusing" of XPD, we have determined that its polarity is Ga termination. The polarity of GaN(0001) surface is also studied by using energy dependence photoelectron diffraction called angle-resolved photoemission extended fine structure, as well as the calculation of multiple scattering cluster models, which confirmed that its polarity is Ga termination.
Hole storage characteristics in Ge/Si hetero-nanocrystal-based memories
Authors: Yang Hong-Guan  , Shi Yi  , Lü Jin  , Pu Lin  , Zhang Rong  , Zheng You-Dou  ,   南京大学物理系，固体微结构物理国家重点实验室，南京 210093
Published: December 2020

Based on analysis of the physical process of hole tunneling, the time characteristics of the writing/erasing and retention in p-channel Ge/Si hetero-nanocrystal-based metal-oxide-semiconductor field-effect transistor(MOSFET) memory have been simulated numerically. Owing to the advantages of a compound potential well and a higher band offset in the valence band, the retention time is increased up to the orders of over 108 and 105, compared with the conventional Si-nanocrystal-based MOSFET memory and the n-channel Ge/Si hetero-nanocrystal-based MOSFET memory, respectively. Moreover, the present device keeps on having high-speed writing/erasing in the direct-tunneling ultrathin oxide regime. It would be expected to solve the contradictory problem between high-speed programming and long retention, therefore, the performance would be substantially improved.
Generation of terahertz radiation via optical rectification and electro-optic detection in ZnTe crystals
Authors: Liu Rui  , Gu Chun-Ming  , He Li-Rong  , Wu Sen  , Shen Wen-Zhong  , Ogawa Hiroshi  , Guo Qi-Xin  ,   (1)上海交通大学物理系凝聚态光谱与光电子物理实验室,上海 200030; (2)佐贺大学理工学部电气与电子工程系,日本佐贺 840-8502
Published: December 2020

We report on the generation of terahertz (THz) radiation via optical rectification and the detection using electro-optic sampling in ZnTe crystal by the pump-probe technique. The pulsewidth of the observed THz radiation is about 0.2 ps, resulting in the wideband THz spectra with a spectral sensitivity beyond 4 THz and the full width at half-maximum of about 2.4 THz. The Jones matrix method has been employed successfully for the calculation of the THz radiation. We study the effects of the optical pulse wavelength, pulsewidth and the ZnTe crystal axis on the generation of THz radiation in the ZnTe crystal. The dependence of the polarization-modulation on the THz detection has also been investigated both experimentally and theoretically by changing the polarization of the probe light.
Enhancement and suppression of the spontaneous emission of a two-level atom in a photonic crystal with a state-conservative photonic pseudogap
Authors: Liu Xiao-Dong  , Wang Yi-Quan  , Xu Xing-Sheng  , Cheng Bing-Ying  , Zhang Dao-Zhong  ,   (1)中国科学院物理研究所光物理实验室，北京 100080; (2)中国科学院物理研究所光物理实验室，北京 100080;大连民族学院机电信息工程系，大连 116600
Published: December 2020

It is shown that there exist a conservation rule of the number of states in a photonic crystal with pseudogaps in the whole frequency regime, and a local conservation rule of the number of states in a photonic crystal with completely photonic band gaps in every band regime. These conservation rules state that, relative to the photonic density of states (DOS) in the effective medium of a photonic crystal, if a valley of the DOS in the photonic crystal appears in some range of frequencies, it must be compensated for by the increases over some other ranges. In this paper, using a model DOS with a state-conservative photonic pseudogap, we obtain naturally the enhancement and suppression of spontaneous emission of a two-level atom in a photonic crystal, and a DOS-induced suppression, enhancement, narrowing and redshift or blueshift of spontaneous emission spectra. Our theory will be especially appropriate in the problem of the spontaneous emission of a collection of dependently emitting atoms or molecules with essentially random dipole orientations in a photonic crystal with a photonic pseudogap.
Small angle x-ray scattering study on microstructure evolution of the aging process of Al-Zn-Mg-Cu-Li alloy
Authors: Zhao Hui  , Du Zhi-Wei  , Zhou Tie-Tao  , Liu Pei-Ying  , Dong Bao-Zhong  , Chen Chang-Qi  ,   (1)北京航空航天大学材料科学和工程学院,北京 100083; (2)中国科学院高能物理研究所同步辐射实验室,北京 100039; (3)中国科学院高能物理研究所同步辐射实验室,北京 100039;鞍山师范学院物理系,鞍山 114005
Published: December 2020

Small angle x-ray scattering technique was used to analyze the variation of microstructure parameters of precipitates in an Al-Zn-Mg-Cu-Li alloy aged at 130, 150 and 160℃ for the same duration. Precipitate particles’ radius increased with aging temperatures, but their specific inner surface and integrated intensities decreased with aging temperatures. The study on Porod curves q3J(q)-q2 indicates that there is a sharp boundary between precipitates and the matrix.
Study on synchronization of chaotic systems based on observer
Authors: Gao Tie-Gang  , Chen Zeng-Qiang  , Yuan Zhu-Zhi  , Gu Qiao-Lun  ,   南开大学信息技术科学学院,天津 300071
Published: December 2020

Synchronization problem of a class of chaotic systems based on observer is proposed. In the article we propose a simple but effective method for synchronization of a class of chaotic systems by the use of state observer，and analyse the stability of the synchronization system. Numerical simulations are presented to show that the method is effective.
On the pressure difference between inside and outside of a droplet in dropwise condensation
Authors: Cao Zhi-Jue  ,   湖南师范大学理学院物理系,长沙 410081;中南大学能源与动力工程学院,长沙 410083
Published: December 2020

From mechanics and energetics point of view, this paper proves concisely that th e pressure difference between inside and outside of a crownshaped droplet on t he surface of a condenser is different from that of a spherical droplet in the c ondenser, and indicates its disagreement with that shown in the paper by Min J C , 2002, Acta Phys. Sin. 51 2730. The reason is given in this pap er.
The application of total internal reflection fluorescence microscopy in single fluorophore molecules axial imaging
Authors: Wang Chen  , Wang Gui-Ying  , Xu Zhi-Zhan  ,   中国科学院上海光学精密机械研究所强光光学开放实验室，上海 201800
Published: December 2020

Here we present a method of modeling fluorophore molecules as spheres in evan escent fields mathematically instead of the assumption of tophat function dist r ibution. Based on this model, we discuss that it is possible to calculate relati ve separation distances of the molecules, and their axial positions and diameters with the total internal reflection fluorescence microscopy(TIRFM) due to its uni que intensity pattern in the z direction. In the whole process, we need mere ly
to change the incident angle once, that is to get only two frame imaging of TIRFM.
Generation of multi-charged ions in laser-induced ionization of methanol under intense nanosecond laser fields
Authors: Kong Xiang-Lei  , Luo Xiao-Lin  , Niu Dong-Mei  , Zhang Xian-Yi  , Kai Rui-Feng  , Li Hai-Yang  ,   中国科学院安徽光学精密机械研究所环境光谱学实验室,合肥 230031
Published: December 2020

The photoionization of methanol seeded in He, N2, Ar gases by an inten se 25ns NdYAG 532nm laser has been studied by timeofflight mass spectrome try . At the laser intensity about 1011W·cm-2, strong multicharged io ns Cq+(q=2—4) and Oq+(q=2—4) appeared in the mass spectra apart from the ions coming from multiphoton ionization (MPI) process when Ar w as used as a carrier gas. From the simulation, we can find the vel ocity of multicharged ions is distributed in Gaussian shape with a FWHM of 6 4×104 m/s. From the experimental results of changing carrier gases and changi ng the delay time of the pulsed electric field, the conclusion can be drawn that th ose multicharged ions come from the Coulomb explosion of methanol cluster ions .
Optical dipole trap in a high-finesse micro-cavity
Authors: Liu Tao  , Zhang Tian-Cai  , Wang  Jun-Min  , Peng Kun-Chi  ,   量子光学与光量子器件国家重点实验室，山西大学光电研究所，太原 030006
Published: December 2020

Optical dipole potential in an inhomogeneous light field is an important method of realizing the laser cooling and trapping of single atoms. The optical dipole trap in the highfinesse microcavity is discussed, and different confi gur ations of optical potential composed of standing wave and vertical confined beam s are analyzed. It is shown that the submicron scale optical trap could be ob t ained in this microcavity with the potential depth of about mK. The strong cou pling of atom and the cavity mode can be realized. We also discuss the effect of laser line width on the depth of potential well.
High power pulse CO2 laser with preionization burst-mode switch technology
Authors: Cheng Zhao-Gu  , Li Xian-Qin  , Chai Xiong-Liang  , Gao Hai-Jun  , Liu Cui-Qing  ,   中国科学院上海光学精密机械研究所,上海 201800
Published: December 2020

By means of a unique electrode construction and preionization burstmode switch technology, 5kW pulse average output is obtained in a transverse flow CO2 las er.
Generation of high-quality soliton pulses using all-fiber optical compressor
Authors: Ding Yong-Kui  , Li Zhi-Yong  , Ni Wen-Jun  , Ge Chun-Feng  , Li Shi-Chen  ,   教育部光电信息技术科学重点实验室，天津大学精密仪器与光电子工程学院，天 津 300072
Published: December 2020

In this paper, optical pulse compression using a dispersion shift fiber and a standard singlemode fiber is demonstrated both analytically and experime nta lly. The effects of fiber and input pulse parameters on the compressing quality are discussed through numerical simulation. Experimental results of compressing puls es generated from a harmonically modelocked fiber laser verify that highqual ity pulses can be obtained using this compression method.
A study on the longitudinal mode behavior of Fabry-Perot cavity composed of fiber Bragg grating
Authors: Lü Chang-Gui  , Cui Yi-Ping  , Wang Zhu-Yuan  , Yun Bin-Feng  ,   东南大学电子工程系，南京  210096
Published: December 2020

The characteristics of transmission spectrum of Fabry-Perot(F-P) cavity composed of two fiber Bragg gratings(FBG) are analysed in this paper. As the influence factors, bandwidth of FBG, phase factor of reflection coefficient of FBG and length of cavity are included. The changes of its characteristics caused by temperature and strain are dicussed. Then the method of how to design this kind of F-P cavity with single mode at the Bragg wavelength of FBG is provided. The numerical simulation spectrum and experimental result are also given.
The prediction feedback control for chaotic systems
Authors: Tang Guo-Ning  , Luo Xiao-Shu  ,   广西师范大学物理与电子科学系，桂林 541004
Published: December 2020

A method of sampled-data and prediction -feedback control for chaotic systems is put forward. By this method,the chaotic Lorenz system and Chua's circuit system can be controlled in assigned equilibrium points and the periodical trajectories. The results of theoretic and numerical calculations indicate that this controlling method is strongly robust.
Annealing effect on the photoluminescence and dangling bonddensity in erbium-doped hydrogenated amorphous silicon
Authors: Zhao Qian  , Wang Bo  , Yan Hui  , M.Kumeda  , T.Shimizu  ,   (1)北京工业大学新型功能材料教育部重点实验室,北京 100022; (2)北京工业大学新型功能材料教育部重点实验室,北京 100022;金泽大学电子、电气与计算机工程系,金泽 920-8667,日本; (3)金泽大学电子、电气与计算机工程系,金泽 920-8667,日本
Published: December 2020

In this paper, Er photoluminescence(PL) of Er-doped a-Si:H films, prepared by rf magnetron co-sputtering with various densities of Si dangling bonds(DBs), was studied with structure modification resulting from post annealing at a temperature range of 200-500℃. It was unexpectedly found that, the intensity of the Er-PL continually increases with annealing temperature below 350℃, meanwhile the density of Si-DBs decreases up to 250℃ due to the structural relaxation but then increases up to 500℃ probably due to Si-H being broken. Since the Er3+ ion transition depends on the symmetry of the Er3+ site in the host. The increase in the Er-PL intensity against the decrease of the density of Si-DBs is probably attributed to a change in the environment of Er3+ ions during annealing.
A notes on the variable separation approach
Authors: Li De-Sheng  , Zhang Hong-Qing  ,   大连理工大学应用数学系，大连 116024;沈阳工业大学理学院，沈阳 110023
Published: December 2020

Starting from the B-cklund transformation and using Cole-Hopf transformation,we reduce a class of nonlinear evolution equations in (2+1)-dimensional spaces to a simple nonlinear evolution equation with two arbitrary functions of {x,t} and {y,t}.We can obtain some new exact solutions of the original equations by studying the simple nonlinear evolution equation which includes some solutions obtained by the variable separation approach.
Electron acceleration by a tightly focused femtosecond laser beam in vacuum
Authors: He Feng  , Yu Wei  , Lu Pei-Xiang  , Yuan Xiao  , Liu Jing-Ru  ,   (1)激光技术国家重点实验室，华中科技大学，武汉 430070; (2)西北核技术研究所，西安 710024; (3)中国科学院上海光学精密机械研究所强光光学实验室，上海 201800; (4)中国科学院上海光学精密机械研究所强光光学实验室，上海 201800;激光技术国家重点实验室，华中科技大学，武汉 430070
Published: December 2020

Ponderomotive-force driven acceleration of an electron at the focus of a high-intensity short-pulse laser is considered using a model that the electrons accelerated are near the focus but decelerated far away the focus. For intensities above 1019Wμm2/cm2, the electron's energy gain in the range of MeV can be realized when the electron leaves the laser pulse. Final energy gain of the electron as a function of its initial position has also been discussed. We find that an electron initially near the focus can be accelerated well.
Quantum entropy of the non-static black hole in（2+1）dimensions
Authors: Sun  Ming-Chao  ,   陇东学院物理系，庆阳 745000
Published: December 2020

In the tortoise coordinates，the quantum entropy of the non-static black hole in (2+1)dimensions due to scalar fields has been investigated by using the brick-wall model.It is shown that the entropy of scalar fields within the thin region near the horizon has the same structure as that of the black ho1e.In particular,the quantum entropy satisfies the perimeter law of the entropy for the static case.
Effects of pump noise and quantum noise with real and imaginary parts correlated on the dynamic properties of a single-mode laser
Authors: Cheng Qing-Hua  , Cao Li  , Wu Da-Jin  , Wang Jun  ,   华中科技大学激光技术国家重点实验室，武汉 430074;荆州师范学院物理系，荆州 434100
Published: December 2020

Adopting the linear approximation method, a loss model for a single-mode laser driven by pump noise and quantum noise whose real and imaginary parts are correlated is studied. We investigated the intensity correlation function, which describes the dynamic property of a laser and varies with time. Moreover, the valid range for the linear approximation method is obtained, and the effects of the intensities of the pump noise and quantum noise on the variance of the laser intensity, and the correlation coefficient between the real and imaginary parts of the quantum noise, are discussed in detail. We find that the valid range is extended in the case of small quantum noise and far form threshold, and it is the largest in the case of small quantum noise, far form threshold and no correlation between the real and imaginary parts of the quantum noise.
Chaotic anti-control of a port control Hamilton system
Authors: Tao Jian-Wu  , Shi Yao-Wu  , Chang Wen-Xiu  ,   空军航空大学，长春 130022
Published: December 2020

Based on the analysis of energy change and dynamical force characteristics for port control Hamiltom (PCH) system, a method of chaotic anti-control is studied via nonlinear output feedback. The proposed method has a clear physical conception and need not estimate the Lyapunov exponent of the chaotic system. This makes the method simpler in practical applications.Numerical studies and computer simulation show the capabilities of this method.
Secure communication method for fast-varying information signal based on chaotic modulation
Authors: Li Jian-Fen  , Li Nong  , Lin Hui  ,   西北工业大学自动化学院，西安 710072
Published: December 2020

A new secure communication method based on chaotic modulation is proposed. The parameter of the transmitting system procreated chaotic carrier is modulated by errors from an adaptive controller and information signal. At the same time, the information is directly multiplied by the chaotic carrier in transmission to drive the receiving system. In the receiver, another adaptive controller is used to maintain chaotic synchronization of the transmitting and receiving systems and to recover information signal. Since the synchronization error is independent of information signal,the chaotic modulation for large-amplitude and fast-varying information signals can be achieved. The results of theoretic analysis and numerical simulation show that the proposed method enhances the degree of security of low-dimensional chaotic systems.
Synchronization and decoding of chaotic lasers and their optimization
Authors: Yan Sen-Lin  , Chi Ze-Ying  , Chen Wen-Jian  , Wang Ze-Nong  ,   南京理工大学电子工程与光电技术学院，南京 210094;南京晓庄学院物理系，南京 210017
Published: December 2020

In this paper,analog signal with 0.1 to 10 GHz frequencies,digital signal with 0.2 and 0.3 Gbit/s rates and frequency shift keying decoding are studied in chaotic lasers.Influences of the frequency and the amplitude of the encoded signals and rate limit of chaotic shift key of lasers on synchronous error are optimally analyzed.Full_synchronization and pseudo_synchronization are discussed.Optimum of the effects of the parameter mismatch and the feedback coefficient on synchronous error and synchronous time is also discussed.
Generation of steady and jitter-free ultra-fast electrical pulses with GaAs photoconductive switches
Authors: Shi Wei  , Ma De-Ming  , Zhao Wei  ,   西安理工大学应用物理系，西安 710048
Published: December 2020

In this paper, experiments of a lateral semi-insulating GaAs photoconductive semiconductor switch triggered by nanosecond, pico-second and femto-second laser pulses were reported. The switches was insulated by solid multi-layer transparent dielectrics. Jitter-free electrical pulse with steady voltage amplitude from the 1mm-gap GaAs switches was observed when biased with a low voltage and triggered by the serial laser pulses. Its change of amplitude was less than 1.2%, the triggered jitter-time was less than 10ps, and pulse width was up to sub-nanosecond. The effect of pulse energy change on the amplitude generated photoconductive semiconductor switch was analyzed. It was indicated that ultra-fast electrical pulse with steady voltage amplitude and pico-second triggered jitter-time can be obtained by controlling switch trigger condition and optimizing the switch design.
A confocal system with two Toraldo pupil filters
Authors: Xiao Fan-Rong  , Yuan Jing-He  , Wang Gui-Ying  , Xu Zhi-Zhan  ,   中国科学院上海光学精密机械研究所，上海 201800
Published: December 2020

Toraldo pupil filter has been one of the most popular pupil filters. But its use is restricted because of the fabrication. In this article, we propose a confocal system with two Toraldo pupil filters. The function of a multi-zone Toraldo pupil filter, which is difficult to fabricate can be substituted by two relatively simple Toraldo pupil filters.
Geometry and electronic properties of Aun（n =2—9）clusters
Authors: Mao Hua-Ping  , Ma Mei-Zhong
Published: December 2020

The possible geometrical and electronic structures of small Aun(n=2—9) clusters are optimized by mean of density functional theory (DFT). The effects of electron correlation is included in these calculations. The ground state equilibrium geometries and the atomization energies of Aun(n=2—9) clusters have been calculated. It is shown that the atomization energy per atom increases with the cluster size.The energy level distribution, the Fermi levels and HOMO-LUMO gaps are investigated. Meanwhile, the electron affinities (EAs) and the ionization potentials (IPs) are calculated. The results are in excellent agreement with those of experiment. The even-odd effects of Fermi energy levels, IPs and EAs with the cluster size are explained.
Numerical analysis of the dispersion of subwavelength diffractive microlens
Authors: Liu Yu-Ling  , Lu Zhen-Wu  ,   中国科学院长春光学精密机械与物理研究所，应用光学国家重点实验室，长春 130022
Published: December 2020

Subwavelength diffractive microlenses are analyzed by use of body-of- revolutionary finite-difference time-domain method. The electric field distributions on the focal plane of the element and the distributions from near field to far field are shown. The dispersion property of subwavelength diffractive microlens is investigated. The dispersion curve in the case of incident wavelength different from the design wavelength is shown. Numerical result illustrates the negative dispersion characteristic of the element, and the increase of focal length is faster than the decrease of incident wavelength.
Nonlinear propagation and supercontinuum generation of a femtosecond pulse in photonic crystal fibers
Authors: Cheng Chun-Fu  , Wang Xiao-Fang  , Lu Bo  ,   中国科学院上海光学精密机械研究所,上海 201800
Published: December 2020

A theoretical investigation with the method of split-step Fourier is presented on the nonlinear propagation and supercontinuum generation of a femtosecond laser pulse in a photonic crystal fiber. The impact of high-order dispersion and nonlinear effects on spectral shape and band width is simulated and analyzed. It is found that soliton self-frequency shift is generated in a photonic crystal fiber. It is also found that intrapulse stimulated Raman scattering and self-phase modulation result in the fine spectral substructure of the supercontinnum. The band width and smoothing of the supercontinuum are found to be related to the higher-order dispersion and the power of the initial laser pulse.
Influence of Stokes component in reflected light on stimulated Brillouin scattering process
Authors: Guo Shao-Feng  , Lu Qi-Sheng  , Cheng Xiang-Ai  , Zhou Ping  , Deng Shao-Yong  , Yin Yan  ,   国防科技大学理学院,长沙 410073
Published: December 2020

A new stimulated Brillouin scattering (SBS) configuration, SSS(Self Stokes Seeding), is presented to describe the influence of Stokes component in a pump light on SBS process. The fast Fourier transform is used to calculate the Stokes energy ratio which denotes the ratio of the energy of Stokes component to that of total pump laser. The coupled SBS equations is solved numerically and the SSS effects is evaluated. The study shows that when the pump laser is reflected normally by the back surface of the flat sample, the Stokes component plays an important role in SBS process, such as decreasing the initiation duration. The larger the Stokes energy ratio is, the shorter the initiation duration is.
The upconversion luminescence research of Er3+-doped heavy metal oxyfluorosilicate glasses
Authors: Xu Shi-Qing  , Wang Guo-Nian  , Zhang Jun-Jie  , Dai Shi-Xun  , Hu Li-Li  , Jiang Zhong-Hong  ,   中国科学院上海光学精密机械研究所,上海 201800
Published: December 2020

The absorption spectrum, upconversion spectra and Raman spectrum of Er3+-doped heavy metal oxyfluorosilicate glasses have been investigated, and luminescence mechanisms of Er3+ in heavy metal oxyfluorosilicate glasses were analyzed. The results showed that blue, green and red emission centered around 411, 525, 543, and 655 nm, corresponding to the 2H9/2→4I15/2,2H11/2→4I15/2,4S3/2→4I15/2, and4F9/2→4I15/2transitions of Er3+ ions, respectively, were simultaneously observed at room temperature under 975 nm diode laser excitation, and the intensity for blue, green and red emissions increases with increasing Er2O3 concentrations. There are two basic upconversion mechanisms: excited state absorption and energy transfer, and a two-photon upconversion process is assigned to the intense green and red emissions, respectively, while a three-photon process is responsible for weak blue upconversion. Raman spectrum indicates that the lead fluoride in the glass network play an important role in upconvesion fluorescence of Er3+.
The effect of Co substitution and stabilizing element on the structure and magnetic properties of Nd3(Fe,Co,M)29(M=Ti,V,Cr) compounds
Authors: Guo Hong-Yong  , Liu Bao-Dan  , Tang Ning  , Luo Hong-Zhi  , Li Yang-Xian  , Yang Fu-Ming  , Wu Guang-Heng  ,   (1)河北工业大学材料学院,天津 300130; (2)中国科学院物理研究所磁学国家重点实验室, 北京 100080; (3)中国科学院物理研究所磁学国家重点实验室, 北京 100080;河北工业大学材料学院,天津 300130
Published: December 2020

The effect of Co substitution and stabilizing elements on the structure and magnetic properties of Nd3Fe29-x-yCoxMy(M=Ti,V,Cr) compounds was investigated by means of x-ray diffraction and magnetic measurements. The results show that all the synthesized compounds have been crystallized in Nd3(Fe,Ti)29type structure with monoclinic symmetry and space group A2/m. The solution of Co element in the compounds is different for the different stabilizing elements. For Cr as the stabilizing element, the pure Co-based 3:29 phase could be obtained and the higher Cr content is required to stabilize the phase with increasing Co content. For Ti and V, the solution of Co in the compounds could be only 6.63 and 12 atoms, respectively. All the Nd3(Fe, Co, M)29compounds show easy-planar type anisotropy at room temperature. For the Nd3(Fe,Co,V)29compounds, the Curie temperature and saturation magnetization increase first and then decrease with further increasing Co content. The spin reorientation temperature shows and increasing tendency except the minimum for x=6 due to the preferential occupation of Co atoms. For the Nd3(Fe, Co, Cr)29compounds, the Curie temperature increases first and then decreases with increasing Co content, but the magnetization is diffcult to be saturated and only shows a decreasing tendency. The spin reorientation transition was only observed for the samples with x=0 and 6.
Study of indium trihydroxide In (OH)Zr3 for ITO
Authors: Zhang Wei-Jia  , Wang Tian-Min  ,   北京航空航天大学理学院，北京 10083
Published: December 2020

The structure of indium trihydroxide In(OH)3 for ITO(Indium Tin Oxide) has been analysed, the Madelung constant and lattice energy of In(OH)3 have been calculated, they are 2.9488 and -509521kJ/mol respectively, and a surface energy approximative expression is given, and then ulteriorly In(OH)3 crystal granule parameters are calculated in preparing nanosized In(OH)3 powder using the method of chemical precipitation,the growth rate 0.012nm/s about is given in this paper.
Pulse laser crystallization of silicon carbon thin films
Authors: Yu Wei  , He Jie  , Sun Yun-Tao  , Zhu Hai-Feng  , Han Li  , Fu Guang-Sheng  ,   河北大学物理科学与技术学院，保定 071002
Published: December 2020

The pulsed laser crystallization of amorphous silicon carbon (aSiC) thin films have been implemented by using XeCl excimer laser. The aSiC thin films were prepared on silicon and quartz substrates by pulsed laser deposition. The surface morphology, atomic order and phase of the asdeposited and post annealing films have been analyzed by atomic force microscopy (AFM) and Raman scattering spectroscopy. AFM results show that aSiC films can be nanocrystallized at a proper laser energy. The size of nanocrystals in the post annealing films increases with the laser energy density; the separation into crystalline silicon and carbon after laser annealing is identified through Raman analysis. The mechanism of the pulsed laser crystallization of aSiC films is discussed to account for the post annealing characteristics.
Microstructural features of DC sputtered vanadium oxide thin films
Authors: Pan Meng-Xiao  , Cao Xing-Zhong  , Li Yang-Xian  , Wang Bao-Yi  , Xue De-Sheng  , Ma Chuang-Xin  , Zhou Chun-Lan  , Wei Long  ,   中国科学院高能物理研究所核分析技术重点实验室；北京 100039;河北工业大学材料科学与工程学院；天津 300130
Published: December 2020

microstructure, thin films of vanadium oxides, preferred orientation, DC magnetron sputtering
Spin polarization study on one-dimensional ferromagnetic metal/conjugated polymers
Authors: Fu Ji-Yong  , Ren Jun-Feng  , Liu De-Sheng  , Xie Shi-Jie  ,   山东大学物理与微电子学院，晶体材料国家重点实验室；济南 250100
Published: December 2020

We investigated theoretically the properties of spin polarization in organic polymer contacting magnetic atoms. Dependence of the spin polarization on the strength of the electron-phonon coupling in a polymer and the spin-dependent effect of the interface coupling were discussed. By modulating the strength of spin splitting, we found that the spin polarization within an organic chain is weaker than that within a metal chain, but stronger than that within a semiconductor.
Investigation of defect properties in doped diamond films
Authors: Hu Xiao-Jun  , Li Rong-Bin  , Shen He-Sheng  , He Xian-Chang  , Deng Wen  , Luo Li-Xiong  ,   上海交通大学金属基复合材料国家重点实验室；上海 200030
Published: December 2020

The defect properties in chemical vapor deposition diamond films doped by sulfur and boron were investigated by the Doppler broadening measurements and electron paramagnetic resonance (EPR). The results show that the defects annihilating the positrons is almost the same in various doped films, and the interactions between the dopants and the positrons are not distinct. In addition, a small amount of boron atoms can improve the quality of diamond films. The EPR signals of the diamond films arise from carbon dangling bonds.
Effect of magnetostatic field on the microstructure of magnesium alloy
Authors: Bao Wei-Ping  , Xu Guang-Ming  , Ban Chun-Yan  , Cui Jian-Zhong  ,   东北大学材料电磁过程研究教育部重点实验室；沈阳 110006
Published: December 2020

Magnesium alloy is a light alloy material with potential applications,but many problems need to be studied for it.In the experiment the process of solidification and the microstructure of magnesium alloy under the effect of magnetostatic field was studied.Some phenomena were found that the microstructures of magliesium alloy were changed obviously:the thickness of grain boundary was reduced，the content of solute in the grain was increased apparently and reduced slightly in the grain boundary.The analysis showed that urlder the effect of magnetostatic field the microstructure of magnesium alloy was improved，and this has great significance to improve the propenies of magnesium alloy.
Form invariance of second-order linear nonholonomic systems in phase space
Authors: Lou Zhi-Mei  ,   绍兴文理学院物理系，绍兴 312000
Published: December 2020

In this paper, the form invariance of second-order linear nonholonomic systems in the phase space is studied. The definition and criterion of the form invariance of secondorder linear nonholonomic systems in the phase space is given. The structure equations and the conserved quantities of the form invariance are obtained. and an example is given to illustrate the application of the results.
The envelope solutions to the coupled nonlinear Schr?dinger equation of Manakov type─with Jacobi elliptic functions
Authors: Shen Shou-Feng  , Pan Zu-Liang  , Zhang Jun  , Ye Cai-Er  ,   (1)北京应用物理与计算数学研究所，北京 100088; (2)浙江大学数学系，杭州 310027; (3)浙江林学院基础部，临安 311300
Published: December 2020

We have simplified the extended Jacobi elliptic function expansion method, namely, improved the modified Jacobi elliptic function expansion method. We applied this method to solve the coupled nonlinear Schr?dinger equation of Manakov type and obtained some Jacobi elliptic envelope solutions and corresponding solitary wave solution, shock wave solution.
Divergence structure for the quantum entropy of black holes in Anti-de Sitter spacetime
Authors: Mi Li-Qin  ,   湛江师范学院物理系，湛江 524048
Published: December 2020

Divergence structure for the quantum entropy of a black hole in Anti-de Sitter spacetime due to the electromagnetic and gravitational fields is investigated by using the brick-wall model. The entropy has both linearly and logarithmically divergent terms, where the linearly divergent term can reduce to the form proportional to the event horizon area if the temperature is replaced by the Hawking temperature and the coordinate cutoff is replaced by the proper cutoff; while the logarithmic divergences not only depend on the characteristics of the black hole but also on the spin of the fields. Since this term exists, the contribution of a spin field in general is not proportional to the scalar one.
Generalized M 2 factor of truncated beams
Authors: Luo Shi-Rong  , Lü Bai-Da  , Sun Nian-Chun  ,   (1)成都东骏激光有限责任公司，成都 611630; (2)四川大学激光物理与化学研究所，成都 610064; (3)四川大学激光物理与化学研究所，成都 610064;江西师范大学物理与通信电子学院，南昌 330027
Published: December 2020

The generalized M2 factor of rotationally symmetric truncated beams is studied in detail by using the asymptotic analysis, generalized truncated second-order moments method and self-convergent beam width approach. The physical relation between the three methods and how to determine the generalized M2 factor in a unified way are analyzed and illustrated with numerical results.
The mechanism of ablation of sapphire by an ultra-short pulse laser
Authors: Li Xiao-Xi  , Jia Tian-Qing  , Feng Dong-Hai  , Xu Zhi-Zhan  ,   中国科学院上海光学精密机械研究所，上海 201800
Published: December 2020

Based on the linear dependence of laser pulse energy on the ablation area, the ablation threshold fluence of sapphire is calculated in this paper. Meanwhile the threshold fluence of sapphire as a function of pulse duration is studied with an ultra-short pulse laser. The experimental results agree well with the theory of avalanche mode. Finally we discussed the photon absorption mechanism of the conduction band electrons in Al2O3.
Spatial chirp and angular dispersion of the nonlinear crystal for a femtosecond optical parametric oscillation
Authors: Ma Jing  , Zhang Ruo-Bing  , Zhao Hua-Jun  , Zhang Wei-Li  , Wang Qing-Yue  ,   天津大学精密仪器与光电子工程学院，光电信息技术科学教育部重点实验室，天津 300072)
Published: December 2020

In this paper the spatial chirp and the angular dispersion for femtosecond optical parametric oscillation(OPO) are calculated theoretically and analysed. The analytical expression of the spatial chirp in the nonlinear crystal(BBO) is presented. And the analytical expressions of second-and third-order dispersions including angular dispersion of the nonlinear crystal for the noncollinearly phase-matched femtosecond BBO OPO in type-Ⅰ configuration with angle tuning. Moreover, variations of second- and third-order dispersions with the angular dispersion are calculated exactly.
Thin-film optical filters with both functions of incident angle and frequency
Authors: Liang Guan-Quan  , Han Peng  , Wang He-Zhou  ,   中山大学光电材料与技术国家重点实验室，广州 510275
Published: December 2020

By coupling two doped one-dimensional photonic crystals, a novel photonic crystal film heterostructure with both functions of frequency and spatial filters is proposed. In a broad frequency range, this optical film filter only transmits light of a selective frequency at normal direction and reflects light of this selective frequency at all other directions; while all other frequencies within the broad frequency range are reflected in any directions.
Frequency-multiplexed fiber-optic Fizeau strain sensor system based on optical amplification
Authors: Jiang Jian  , Rao Yun-Jiang  , Zhou Chang-Xue  , Zhu Tao  ,   重庆大学光电工程学院，重庆 400044
Published: December 2020

A novel method for multiplexing fiber-optic Fizeau strain sensors based on optical amplification is proposed and demonstrated for the first time to our knowledge. This method overcomes the two intrinsic disadvantages of fiber-optic Fabry-Perot strain sensors, i.e. weak signal and difficult multiplexing. Also, the amplified spontaneous emission and optical amplification of the Erbiumdoped fiber pumped by a 980nm laser diode are used simultaneously. The structure, principle and experimental results of the sensor system are described in this paper. A strain accuracy of ～±10με has been achieved, which can meet the practical requirement.
Theoretical study on the nuclear fusion mechanism of deuterium clusters aroused by Coulomb explosions with femtosecond intense laser
Authors: An Wei-Ke  , Qiu Xi-Jun  , Zhu Zhi-Yuan  ,   (1)上海大学理学院物理系，上海 200436; (2)上海大学理学院物理系，上海 200436;岳阳师范学院物理系，岳阳 414000; (3)中国科学院上海原子核研究所，上海 201800
Published: December 2020

Considering the Coulomb explosion induced by the interaction of a deuterium cluster target with an ultra-intensie femtosecond laser, the mechanism which generates energetic deuterium nuclei for the fusion has been analyzed．The formulas for expansions of deuterium ion clusters, which are driven by Coulomb explosion, are proposed; and hence the kinetic energies of deuterium nuclei and the expansion time of deuterium ion clusters have been estimated．
Study on laser-micro-Raman spectra in near-stoichiometric LiNbO3 crystals
Authors: Sun Dun-Lu  , Qiu Huai-Li  , Hang Yin  , Zhang Lian-Han  , Zhu Shi-Ning  , Wang Ai-Hua  , Yin Shao-Tang  ,   (1)南京大学固体微结构物理国家重点实验室,南京 210093; (2)中国科学院安徽光学精密机械研究所,合肥 230031; (3)中国科学院上海光学精密机械研究所,上海 201821
Published: December 2020

The laser-micro-Raman spectra of near-stoichiometric LiNbO3 crystals were measured and analyzed. The crystals were grown by flux pulling method. Compared with the congruent LiNbO3 crystal, the number and frequency of Raman spectral lines of A1(TO) and E(TO) modes have no change. It was validated that the LiNbO3 crystal is substitutional solid solution. The relative intensity of 738cm-1 Raman peak(A1(LO)) exhibited obvious change when the Li2O contents increase in pure LiNbO3 crystal, the 738cm-1 Raman peak disappeared in the Mg-doped and Zn-doped LiNbO3 crystals. These Raman peaks were discussed and explained from the occupied site and structure according to the Li vacancy model. The full width at half maximum (FWHM) of the 152 and 872cm-1 Raman peaks narrows with increasing the Li/Nb in the crystals. Their relationships were fitted linearlly, using the fitting equation, and the Li/Nb ratio can be calculated according to the FWHM of Raman peaks.
Gaussian model with triplet-spin interactions on the Sierpinski gasket lattice
Authors: Liu Jie  , Kong Xiang-Mu  , Li Yong-Ping  , Huang Jia-Yin  ,   (1)青岛大学理工学院物理系,青岛 266071; (2)曲阜师范大学物理系,曲阜 273165; (3)曲阜师范大学物理系,曲阜 273165;北京师范大学物理系和理论物理研究所,北京 100875
Published: December 2020

Using the renormalization-group transformation and cumulant expansion technique, the Gaussian model with two-spin interactions and triplet-spin interactions on the Sierpinski gasket lattice is studied, and its fixed points and critical exponents are obtained. Compared with the case of only two-spin interactions, the fixed points and critical exponents have changed. The results show that the fixed points and critical exponents are all dependent on triplet-spin interactions in the cases with or without external field.
Influence of hydrogen-enhanced etching on the quality of diamond films and the existing form of sp2 bonding carbon atoms
Authors: Ma Bing-Xian  , Yao Ning  , Yang Shi-E  , Lu Zhan-Ling  , Fan Zhi-Qin  , Zhang Bing-Lin  ,   郑州大学物理工程学院,郑州 450052
Published: December 2020

Diamond thin films were prepared by using chemical vapor deposition. It is enhanced to etch the sp2 bonding carbon atoms of the film by intermittently closing the methane gas during the deposition. These films were characterized by Raman spectroscopy and microscopy. The results show that the enhanced etching of sp2 bonding carbon atoms has no obvious effect on quality and microstructure of the diamond films. It reveals that the sp2 bonding carbon atoms do not mainly exist in graphitic or amorphous carbon grain form in the films but mainly among the carbon atoms of diamond grain surface or grain boundary.
Field matching analysis of abrupt cavities with absorbing materials
Authors: Luo Yong  , Li Hong-Fu  , Xie Zhong-Lian  , Yu Sheng  , Deng Xue  , Zhao Qing  , Xu Yong  ,   电子科技大学物理电子学院，成都 610054
Published: December 2020

Absorbing material is used to reduce the Q factors of resonant cavities, enhance the bandwidth and restrain the competitive modes in high-power microwave devices. In this paper, solving field in absorbing material and field matching method were used to derive the dispersion equation in waveguides and field matching formulas of hybrid modes (HEM) in an abrupt cavity with absorber. Based on the theoretical analysis, numerical simulations of the cavities in gyroklystrons were done.The influence of absorber on transmission and attenuation in waveguides, the loss and resonance characteristic and quality factors in cavities has been studied. The main results are presented.
Theoretical study on dispersion relation of one-dimensional copolymers
Authors: Zhang Da-Cheng  , Cheng Jie  , Liu De-Sheng  , Xie Shi-Jie  ,   山东大学物理与微电子学院，晶体材料国家重点实验室,济南 250100
Published: December 2020

Lattice vibration of one-dimensional copolymer chains was studied and the dispersion relation was obtained numerically. The character of the vibration modes was recognized. It was found that the interface modes may appear if the homopolymer blocks have a strong interaction with each other, whose frequencies lie in the band gap between the acoustic and optical branches or between two optical branches. The character of the organic quantum well or superlattice of a copolymer chain was discussed from the view point of vibration modes.
Preisach analysis of La0.67Pb0.33MnO3
Authors: Xiao Chun-Tao  , Cao Xian-Sheng  ,   兰州大学磁学与磁性材料教育部重点实验室，兰州 730000
Published: December 2020

The perovskite La0.67Pb0.33MnO3 with a Curie temperature TC=360K has been characterized by measuring the zero-field-cooled(ZFC) and field-cooled(FC) moments over a wide range of temperature 2K<T<380K in the applied field of ha=3978.87A/m, and also the major hysteresis loop over the field range |ha|≤160kA/m at T=10K. The data have been analysed within the framework of a generalized version of the Preisach model of the hysteresis,which combines thermal fluctuations with the growth of the free energy barriers below TC. Numerical simulations replicate all of the principal structural systematics of the data, including the hystersis loop and the magnetization and the susceptibility under the ZFC/FC conditions. Finally, the details of the spectrum of Barkhausen instabilities are discussed in this material.
Growth of highly c-axis oriented K:SBN thin films on Si(100) by the sol-gel method
Authors: Cao Xiao-Yan  , Ye Hui  , Deng Nian-Hui  , Guo Bing  , Gu Pei-Fu  ,   浙江大学现代光学仪器国家重点实验室，杭州 310027
Published: December 2020

Ferroelectric SrxBa1-xNb2O6 (0.2＜x＜0.8, SBN100 x＝ thin films of highly preferred c axis orientation have been grown on Si (100) substrate by the sol-gel method with post annealing at 1000°C. Investigated by x-ray diffraction and second ion mass spectrum,we observed that the SBN thin films prepared using NbCl5 precursor solution contained K+ ions, compared with Nb(OC2H5)5 precursored SBN films. By choosing appropriate contents of K+ there exists the optimum preferred orientation in SBN thin film.K ions dissolving in SBN cell and entering Si substrate can make SBN cell and Si cell a small twist simultaneously,which improves the matching of the film and the substrate to promote the high c axis superior growth.Finally,the optic characteristics of thin films have been tested.
Anomalous hopping and tunneling effects on the conductivity ofa wedge-shaped Au film system
Authors: Tao Xiang-Ming  , Xia A-Gen  , Ye Gao-Xiang  ,   浙江大学物理系，杭州 310027
Published: December 2020

A gold thin film percolation system, deposited on glass surfaces by the vapor deposition method, has been fabricated. By using the expansive and movable properties of silicone oil drop, a characteristic wedge - shaped film system with a slope of ～ 10-5 naturally forms during deposition. The electrical conductivity of the band-like gold film, i.e., the uniform part with a fixed thickness, is measured with the four-probe method. It is found that hopping and tunneling effects of the films are stronger than those of the other films.
Variable separation solution and new soliton structures in the (2+1)-dimensional nonlinear Burgers equations
Authors: Xu Chang-Zhi  , Zhang Jie-Fang  ,   (1)浙江师范大学非线性物理研究所，金华 321004; (2)浙江师范大学非线性物理研究所，金华 321004;金华教育学院物理系，金华 321000
Published: December 2020

A variable separation approach is applied to obtain the new exact explicit solution of (2+1)dimensional nonlinear Burgers equations. Using a B-cklund transformation and the variable separation technique, we find the variable separation solution of the (2+1)dimensional Burgers equations by the entrance of there arbitrary functions (one condition function) for the seed solution. Some special type of the kink soliton solution, periodic soliton solutions and lattice soliton solutions are discussed by selecting the arbitrary functions appropriately.