bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantum fluctuations of the optical parametric amplification system under the consideration of dispersion
Authors: Zhao Chao-Ying  , Tan Wei-Han  ,   (1)杭州电子科技大学理学院，杭州  310018；山西大学光电研究所，量子光学与光量子器件国家重点实验室，太原  030006; (2)上海大学物理系，上海  200444
Published: December 2020

In this paper, we first find out the analytic solution of the time-dependent Fokker-Planck equation of the non-degenerate optical parametric amplification (NOPA) system under the consideration of the dispersion, the loss and the pump depletion effects. Then, through the numerical calculation, we obtain the squeezing characteristic of the degenerate optical parametric amplification (DOPA) system with dispersion. the research indicates: the dispersion effect stems from the nonlinear susceptibility change from χ″ toχ″/{1+σ2/}/+2, with the increasing of the dispersion effect, the general feature of the squeezing curves beeps unchanged, and the curves contract toward left. The maximum squeezing approaches to the linear theory 1/(1+μ). Finally, we obtain the entanglement characteristic of the NOPA system with dispersion. We find out when σ is given, with the increasing of pump parameter μ, he corresponding phase makes a large change. The nonlinear susceptibility changes many times. When the polarity is positive, the system obtains the gain, when the polarity is negative, the system suffers the loss, but the gain is mainly dissipated by the loss, so the net gain is small, the squeezing is also small. The minimum variance V1 reduces gradually, and the whole curve moves to the right, approaches to the linear theory 1/(1+μ).
Focusing properties of the uniaxially anisotropic metamaterial slab lens
Authors: Liu Hong-Yao  , Lü Qiang  , Luo Hai-Lu  , Wen Shuang-Chun  ,   湖南大学计算机与通信学院微纳光电器件及应用教育部重点实验室，长沙  410082
Published: December 2020

We studied the focusing properties of an anisotropic metamaterial slab lens by means of the angular spectrum representation of the vectorial electromagnetic field. The analytical expressions for vectorial fields in all the propagation regions are obtained，and the quantitative relationship between the focusing characteristics of the vectorial electromagnetic field and the anisotropic parameters of the anisotropic metamaterial slab lens is disclosed. The polarization state of the focusing beam is found to be changed due to the effect of anisotropy. As an application of the vectorial theory，we have analyzed the focusing property of an anisotropic metamaterial slab for which the permeability along longitudinal axis is -1. It is demonstrated that this slab lens can redirect a beam initially polarized along a transverse axis to a partial focus and give a clear polarization rotation of the beam.
Observation of micro-arc cascade in vacuum short gap
Authors: Cao Zhu-Rong  , Ding Yong-Kun  , Liu Shen-Ye  ,   中国工程物理研究院激光聚变研究中心，绵阳 621900
Published: December 2020

The cascade effect of cathode spots from vacuum micro-arcing has been observed by micro-channel plate (MCP) imager in divect current mode. The spots-track on MCP surface can be drawn out as a multiform dog-leg path，and betweencenters of spots is 200—300 μm. The first spot is always the lucida，and its intensity is about decuple of its sub-spots. The intensity between cascade sub-spots is at the same level，and sub-spots are nondestructive for MCP cathode surface. The experiments showed that arcing of sub-spots depends on emission of the first spot.
The first-principles study of absorption spectrum of C-doped anatase TiO2
Authors: Xu Ling  , Tang Chao-Qun  , Qian Jun  ,   (1)华中科技大学物理学院，武汉  430074; (2)武汉大学印刷与包装系，武汉  430072
Published: December 2020

We have performed first-principle calculations of electronic band structure of C-doped anatase TiO2, and explained some experimental phenormena of C-doped TiO2s absorption spectrum. The results indicated that the band gap broaders and some new bands appears in the band gap. These new bands result from C 2p orbitals, they are separated, and their existance explains the visible light response. The electrons in the valence band can be excited to the new states and subsequently excited to the conduction band, leading to existence of two absorption edges. Theoretical result are in agreement with the experimental result.
Dielectric properties of Eu-doped polycrystalline TbMnO3
Authors: Guo Xi  , Wang Xia  , Zheng Wu  , Tang Wei-Hua  ,   (1)北京凝聚态物理国家实验室，中国科学院物理研究所，北京 100190；浙江理工大学光电材料与器件中心，杭州 310018; (2)首都师范大学物理系，北京 100037; (3)浙江理工大学光电材料与器件中心，杭州 310018
Published: December 2020

Polycrystalline bulk Tb0.8Eu0.2MnO3 was prepared by solid phase reaction. The XRD analysis of the sample showed that the Eu3+ had been doped in TbMnO3. Dielectric properties were examined as functions of temperature (100 K ≤T≤ 300 K) and frequency (200 Hz≤ f ≤100 kHz). Two dielectric relaxations were found in these ranges. By means of analysis the low-temperature relaxation was ascribed to the dipolar effects induced by carriers hopping; and the high-temperature relaxation was found to originate from the internal barrier-layer capacitor effects of ion conductivity. The measurement of resistivity showed that there is a marked transition around 230 K, indicating that different conductive mechanisms underlay the transport processes.
A novel photonic crystal slab waveguide with dispersionless slow light
Authors: Shen Hong-Jun  , Tian Hui-Ping  , Ji Yue-Feng  ,   (1)北京邮电大学信息光子学与光通信教育部重点实验室,北京  100876; (2)北京邮电大学信息光子学与光通信教育部重点实验室,北京  100876；宁夏大学物理电子信息学院，银川  750021
Published: December 2020

We report a low loss photonic crystal slab waveguide formed by deforming the innermost holes on either side of a single line defect so that the circular air holes are changed to elliptical holes. The group velocity and group velocity dispersion of this waveguide depend strongly on the innermost elliptical air holes. We obtain the photonic bands and group index of guided modes in this kind of photonic crystal waveguide by guided mode expansion method and investigate the dependence of photonic bands and group index of guided modes in this photonic crystal waveguide on the parameter of the innermost elliptical air holes. For waveguides with the optimum innermost elliptical air holes, we achieved a wider single mode region below the light line, in which light can easily propagate without intrinsic loss. At the same time, this kind of waveguide has nearly constant group velocity and vanishing group velocity dispersion in a 3—5 nm bandwidth. These results will be applicable to design and fabricate photonic crystal slab waveguides with low group velocity, low dispersion and low loss characteristics.
Nonorthogonal decoy-state quantum key distribution based on conditionally prepared down-conversion source
Authors: Hu Hua-Peng  , Wang Jin-Dong  , Huang Yu-Xian  , Liu Song-Hao  , Lu Wei  ,   (1)华南师范大学信息光电子科技学院光子信息技术广东省高校重点实验室,广州  510006; (2)中国科学院合肥智能研究所，合肥  230031
Published: December 2020

The decoy-state method and the non-orthogonal encoding protocol, being capable of resisting the photon-number splitting attack, have become attractive recently. Here, we combine both the methods and propose a new protocol using a conditionally prepared down-conversion source, following Poisson photon number distribution. In the protocol, Alice randomly changes the intensities of the pump light so that the intensity of signal photon of photon pair is randomly changed. The signal state is used for generating keys, the decoy states for detecting the eavesdropping and estimating the fraction of single-photon and two-photon pulses. We have simulated the final key rate over transmission distance, showing our scheme can enhance the performance of quantum key distribution.
Spectroscopic properties and Judd-Ofelt theory analysis of La, Nd codoped Y2O3 high refractivity transparent ceramics
Authors: Huang Yi-Hua  , Jiang Dong-Liang  , Zhang Jing-Xian  , Lin Qing-Ling  ,   (1)中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室，上海  200050; (2)中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室，上海  200050；中国科学院研究生院，北京  100049
Published: December 2020

Nd，La:Y2O3 nanocrystalline powder was prepared by co-precipitation method. The transparent ceramic was fabricated by vacuum sintering at 1700℃ for 4 h in vacuum. Transparent polycrystalline ceramics with uniform lanthanum distribution was obtained. The grain size was around 22 μm. No pores were found in the grain and grain boundary. The absorption spectrum and the fluorescence spectrum of the sample were measured. The highest absorption peak is centered at 821 nm and the absorption cross section is 43×10-24 m2 The main emission peak is at 1078 nm, and the fluorescence lifetime is 0287 ms. The Judd-Ofelt intensity parameter Ωλ（λ=2，4，6）, spontaneous transition probability, radiative lifetime and fluorescence branching ratio of Nd3+ were calculated by Judd-Ofelt theory. The calculated emission cross section of 4F3/2→4I11/2 transition is 20×10-24 m2 It was found that the addition of La ion can change the crystalline field of yttria, which helps to obtain suitable solid laser materials.
Two-dimensional complex nano-micro patterning on GaP and ZnSe surface created by the interference of three femtosecond laser beams
Authors: Xiong Ping-Xin  , Jia Xin  , Jia Tian-Qing  , Deng Li  , Feng Dong-Hai  , Sun Zhen-Rong  , Xu Zhi-Zhan  ,   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

In this paper, we reported the two-dimensional periodic nano-micro complex structures on GaP and ZnSe crystals surface created by the interference of three femtosecond laser beams. Different types of nano-patterns were obtained by arranging the laser polarization combination of the three beams. In order to understand the formation of these nanopatterns, we theoretically calculated the distributions of laser intensity and polarization. The experimental and theoretical results indicate that the long periodic microsturctures are determined by the interferential intensity pattern, and the short periodic nanostructures were determined by the interferential polarization pattern. These researches haue huge potential applications in nanopattering of semiconductors and dielectrics.
Stochastic functional analysis of propagation and localization of cylindrical wave in a two-dimensional random medium
Authors: Ding Rui  , Jin Ya-Qiu  , Ogura Hisanao  ,   (1)复旦大学波散射与遥感信息教育部重点实验室,上海 200433; (2)京都大学电子工程系，日本京都 606-01
Published: December 2020

Propagation and localization of cylindrical wave in a two-dimensional isotropic and homogeneous random medium is studied. By expanding the random permittivity fluctuation in the form of a Wiener integral equation in the frequency domain, and representing the wave fields by a linear combination of outgoing and incoming waves, the scalar Helmholtz equation is solved by means of stochastic functional approach to obtain the analytical expression of cylindrical wave. The spatial wave energy distribution is derived to demonstrate the localization phenomenon, and the localization length is also calculated. Compared with the waves in non-random medium, the wave transfer equation between plane wave and cylindrical wave in random medium shows an additional exponential factor to indicate the modulation effects due to the medium randomness in both the amplitude and the phase. Numerical simulations are presented to illustrate the functional dependence of the localization phenomenon.
Complexity of multi-architecture type of deterministic weighted generalized Farey organized network pyramid
Authors: Liu Qiang  , Fang Jin-Qing  , Li Yong  ,   中国原子能科学研究院核技术应用研究所,北京  102413
Published: December 2020

Three types of deterministic weighted generalized Farey organized network pyramids(so-called WGFONP-1,WGFONP-2, WGFONP-3) are constructed, and the topological characteristics (degree distribution, average path length, clustering coefficient, assortative coefficient and so on) of network pyramids are studied by theoretical and numerical analyses. Using Farey sequence as determinacy, randomicity and hybrid weights of network nodes, we calculate and fit the strength distribution and the weight distribution of the network pyramids, as well as tentatively reveal the complexities and the diversities of the WGFONP-1,WGFONP-2 and WGFONP-3. These results can conduce to the understanding of complexities and diversities of a number of practical networks.
Thermodynamic property of a relativistic Fermi gas trapped in hard-sphere potential
Authors: Fan Zhao-Lan  , Men Fu-Dian  , Dou Rui-Bo  ,   (1)青岛拓谱信息工程专修学院，青岛  266555; (2)中国石油大学（华东）物理科学与技术学院，东营  257061
Published: December 2020

Using the methods of numerical simulation and quantum statistics, based on the thermodynamic quantities of Fermi gas trapped in a general external potential, we studied the thermodynamic properties of a relativistic Fermi gas trapped in hard-sphere potential, gave the analytical expressions of the energy and heat capacity of the relativistic Fermi system, and analyzed the influence of the relativistic effect on the energy and heat capacity. The results showed the energy and heat capacity of the relativistic Fermi system is larger than those of the nonrelativistic case. The larger the relativistic eigenvalue, the lower the change temperature of heat capacity. As the temperature rises, the larger the relativistic eigenvalue, the greater the energy.
Analysis of bursting phenomena in Chen’s system with periodic excitation
Authors: Zhang Xiao-Fang  , Chen Zhang-Yao  , Bi Qin-Sheng  ,   江苏大学理学院，镇江 212013
Published: December 2020

For the periodically excited Chens system, when there exists order gap between the natural frequency of the original system and the excited frequency, dynamical behaviors associated with the two different time scales can be observed. Bifurcations of the system have been presented by considering the variation of the excited term. Fast-slow analysis is employed to explore the evolution of the system with different parameter conditions, which gives different types of bursters such as symmetric fold bursting, symmetric subHopf bursting and symmetric Hopf-homoclinic bursting, as well as the bifurcation mechanism. Furthermore, the influence of both the amplitude and the frequency of the excitation on the bursting is discussed in detail.
Scattering channel in focus imaging of two-dimensional phononic crystal panel
Authors: Li Xiao-Chun  , Gao Jun-Li  , Liu Shao-E  , Zhou Ke-Chao  , Huang Bo-Yun  ,   (1)中南大学粉末冶金研究院,长沙  410083; (2)中南大学物理科学与技术学院，长沙  410083; (3)中南大学物理科学与技术学院，长沙  410083；中南大学粉末冶金研究院,长沙  410083
Published: December 2020

By using multiple-scattering theory (MST), the imaging process was investigated in steel/water phononic crystal panel with negative refraction. It was found there are some channels for the scattering waves propagating in the panel. For a given source location, the scattering channel changes with incident angle and so does the strength of signal coupled to the channel. While small-angle incident wave can be coupled into the channel perfectly, large-angle incident wave which is strongly scattered in the incident surface can be coupled into the channel only weakly. In the non-ideal imaging case, imaging position changes with the angle of incidence signal,it further causes imaging aberration. These scattering channels are closely related to the anisotropic band structure of the crystal panel and multiple scattering of the rods, and vary with position change of the sound source.
A new method of polarization measurement based on the novel polarization interference imaging spectrometer
Authors: Sun Yao  , Zhang Chun-Min  , Du Juan  , Zhao Bao-Chang  ,   西安交通大学理学院，非平衡物质结构与量子调控教育部重点实验室，西安 710049
Published: December 2020

A new spaceborne remote sensing principle and method of two-dimensional object polarization measurement, which is based on the novel polarization interference imaging spectrometer (NPIIS) using the field of view compensated Savart polariscope, is presented. Without modification of the optical system of the NPIIS, the Stokes vector, the degree of polarization and polarization direction expressions are derived by measuring the intensity of one pixel on the image plane after three rotations of the polarization interferometer. The method and principle is verified by computer simulation, and the results appear to be well consistent with the theoretical analysis. The research extends the measurement function of the interference imaging spectrometer. Compared with the existing imaging spectrometers which can measure the two-dimensional image information and one-dimensional spectral information, another method to acquire the object information by measuring the polarization state is developed.
Study of chaotic bandwidth in erbium-doped ring fiber laser
Authors: Yang Ling-Zhen  , Qiao Zhan-Duo  , Wu Yun-Qiao  , Wang Yun-Cai  ,   太原理工大学物理系，太原 030024
Published: December 2020

Based on nonlinear Kerr effect model of erbium-doped ring fiber laser, the influences of pump power and nonlinear coefficient on chaotic bandwidth are investigated. The results indicate that, with fixed nonlinear coefficient, the bandwidth of the chaos increases first and then decreases with the increasing of pump power. Fixing the pump power at 01 W, the chaotic bandwidth rises up to 153 GHz with the nonlinear coefficient increased to 45 W-1km-1. On further increasing the nonlinear coefficient the chaotic bandwidth is reduced gradually.
Experimental study of slow light based on four-wave mixing wavelength conversion and dispersion in optical fibers
Authors: Yin Jing-Chan  , Xiao Xiao-Sheng  , Yang Chang-Xi  ,   清华大学精密仪器与机械学系，精密测试技术与仪器国家重点实验室，北京  100084
Published: December 2020

Slow light based on four-wave mixing (FWM) wavelength conversion and dispersion is experimentally studied. The FWM bandwidth of the highly nonlinear fiber is measured to be 40 nm, which is also the slow light tunable bandwidth. A 34 ns delay of 500 MHz sine signal is achieved in standard single mode fiber, and 198 ns delay of short pulses with 100 ps width is achieved in dispersion compensation fiber (DCF). An advancement of 209 ns for the 100 ps short pulses is also achieved in the DCF. The method to increase the slow light delay is discussed, and large delay up to microseconds is expected when wideband FWM wavelength conversion and large dispersion fibers are used. The expected large delay will help us realize high efficiency fiber delay lines and all-fiber buffers.
The pulsating propagation of spatial soliton in strongly nonlocal optical lattice
Authors: Zhou Jun  , Ren Hai-Dong  , Feng Ya-Ping  ,   宁波大学物理系，宁波  315211
Published: December 2020

Based on the nonlocal nonlinear Schrdinger equation, which is the evolution equation of propagation of spatial soliton in the nonlocal media, the pulsating propagation of spatial solitons in one-dimensional strongly nonlocal optical lattice are researched numerically by the split-step Fourier method. The pulsating propagation period of spatial soliton is analyzed for different parameters of propagation, such as the initial energy of the beam, the nonlocality degree, the modulation degree of lattice, the period of the transverse modulation and the asymptotic rate of the longitudinal modulation of linear refractive index. And the inherent physical mechanisms of pulsating propagation of spatial soliton are discussed for the different parameters of lattice structure. Furthermore, the controllable switching behavior of spatial optical soliton has been achieved in the strongly nonlocal optical lattice with longitudinal modulation of linear refractive index.
Transmission properties of the system of dielectric spheres periodically mounted in a metal slab
Authors: Zheng Jun-Juan  , Sun Gang  ,   (1)中国科学院物理研究所北京凝聚态物理国家实验室，北京  100190; (2)中国科学院物理研究所北京凝聚态物理国家实验室，北京  100190；北京服装学院基础教学部，北京  100029
Published: December 2020

Transmission properties of the system of dielectric spheres periodically mounted in a metal slab are investigated. The electromagnetic wave can enter the dielectric spheres by tunneling effect and exists as a cavity mode. The surface plasmon polaritons can occur at certain frequency because of the periodically mounted dielectric spheres, which effectively modulate the metal surface to a periodical structure. When the frequencies of the cavity mode and that of the surface plasmon polaritons are close to each other, the coupling between them can greatly enhance both the electromagnetic modes, which results in a very strong electric field in the dielectric spheres of the upper layer. This strong electric field can further enter partially the dielectric spheres at the lower layer by tunneling effect, and can propagate out of the metal slab by the similar mechanism at the upper side of the metal slab, which causes additional increment in the transmission.
Design and experimental verification of left-handed metamaterials based on inter-unit-cell coupling
Authors: Wang Jia-Fu  , Qu Shao-Bo  , Xu Zhuo  , Zhang Jie-Qiu  , Ma Hua  , Yang Yi-Ming  , Wu Xiang  , Lu Lei  ,   (1)空军工程大学理学院，西安 710051; (2)空军工程大学理学院，西安 710051；西安交通大学电子陶瓷与器件教育部重点实验室，西安 710049; (3)西安交通大学电子陶瓷与器件教育部重点实验室，西安 710049
Published: December 2020

A method of designing left-handed metamaterials based on inter-unit-cell coupling was proposed in this paper. A theoretical model was established using equivalent circuit theory. By properly setting the geometrical parameters of adjacent unit cells, the electric resonance frequency can be made equal to the magnetic resonance frequency. Thus, the left-handed bandwidth reaches its maximum. A typical left-handed metamaterial based on inter-unit-cell coupling was fabricated and tested. The experimental results show that the test sample has equal electric and magnetic resonance frequencies and the left-handed bandwidth is 24 GHz. This verifies the design method proposed in this paper.
Design of all-solid octagon photonic crystal fiber with large mode area
Authors: Guo Yan-Yan  , Hou Lan-Tian  ,   (1)燕山大学红外光纤与传感技术研究所，秦皇岛  066004; (2)燕山大学红外光纤与传感技术研究所，秦皇岛  066004；燕山大学亚稳材料制备技术与科学重点实验室，秦皇岛  066004
Published: December 2020

In this paper, a novel all-solid octagonal Yb3+-doped photonic crystal fiber (PCF) with large mode area and low loss is proposed. The air holes in the cladding are replaced by the B2O3-doped quartz rods，which increases the thermal damage threshold of the PCF and simplifies the fabrication process. The properties of the PCF are investigated by multi-pole method. Simulation results show that the effective mode area of this PCF is up to 2000 μm2, and the bending loss for a bending radius of 5 cm is as low as 05 dB/m at 1064 μm. Also, this PCF can support effectively single-mode operation. The design results of this paper are highly meaningful for the development of fiber lasers and fiber amplifiers.
Effect of pinhole diameter on measurement accuracy of self-referencing interferometer wavefront sensor
Authors: Bai Fu-Zhong  , Rao Chang-Hui  ,   (1)中国科学院光电技术研究所，成都  610209；中国科学院自适应光学重点实验室，成都  610209; (2)中国科学院光电技术研究所，成都  610209；中国科学院自适应光学重点实验室，成都  610209；内蒙古工业大学机械学院，呼和浩特  010051；中国科学院研究生院，北京  100049
Published: December 2020

The diameter of pinhole is a critical element that affects the measurement accuracy of self-referencing interferometer wavefront sensor (SRIWFS), and its dimension is determined by the accuracy requirement of practical measurement and the intensity transmission. The effects of pinhole diameter on quality and intensity transmission of reference wave are analyzed on the basis of the Fourier optics theory, and then they are verified by numerical simulation and experiment. These results demonstrate that to obtain a good approximation to a reference wave, the pinhole diameter should equal half of the Airy-disk diameter produced by an unaberrated optic. In this way, the root-mean-square value of the reference wavefront is less than λ/100 for all aberrations with the peak-to-valley value of not smaller than one wavelength. These theoretical analyses and experimental results provide a valuable reference and illumination for determining the dimension of pinhole along with the analysis or design of SRIWFS for various testing tasks.
Effect of device parameters on propagation of plasma surface wave excited by slot antenna
Authors: Lan Chao-Hui  , Hu Xi-Wei  , Jiang Zhong-He  , Liu Ming-Hai  ,   (1)华中科技大学电气与电子工程学院，武汉  430074; (2)中国工程物理研究院流体物理研究所，绵阳  621900
Published: December 2020

The plasma surface wave propagation in a rectangular structured device is simulated using the finite-difference time-domain method. The effect of device parameters on the propagation of plasma surface wave excited by slot antenna array is investigated. The parameters considered include the relative permittivity and thickness of dielectric slab, and the air gap on the top of dielectric slab. Appropriate parameters for the relative permittivity and thickness of dielectric slab are obtained through simulations, and it is found that the existence of air gap would greatly weaken the excitation of surface wave. The simulation results provide a good reference for the design optimization of large-scale rectangular surface-wave plasma source.
Investigation on the crack healing effect in dimethyl phthalate series glassy materials
Authors: Guo Xiu-Zhen  , Zhou Heng-Wei  , Zhang Li-Li  , Wu Wen-Hui  , Zhang Jin-Lu  , Huang Yi-Neng  ,   (1)南京大学物理系，固体微结构实验室，南京  210093; (2)伊犁师范学院物理与电子信息学院，凝聚态物理与材料设计研究所，伊宁  835000; (3)伊犁师范学院物理与电子信息学院，凝聚态物理与材料设计研究所，伊宁  835000；南京大学物理系，固体微结构实验室，南京  210093
Published: December 2020

The stress cracking and crack-healing effects in dimethyl phthalate, diethyl phthalate, dibutyl phthalate and dioctyl phthalate series glassy materials was measured by the recently invented method (RMS-L-CH) which measures the stress cracking and crack healing in situ and further analysis and discussions on the crack healing phenomenon as well as its relation to the glass transition are presented. The results validate that the RMS-L-CH method is effective and may provide a new means to characterize the glass transition and to probe into the glass transition mechanism.
Polymer white light-emitting diodes with a single emission layer of fluorescent polymer blend
Authors: Wang Bao-Zheng  , Zhang An-Qi  , Wu Hong-Bin  , Yang Wei  , Wen Shang-Sheng  ,   (1)华南理工大学高分子光电材料与器件研究所，广州  510640; (2)华南理工大学高分子光电材料与器件研究所，广州  510640；华南理工大学特种功能材料及其制备新技术教育部重点实验室，广州  510640
Published: December 2020

White polymer light-emitting diode with a single layer of fluorescent polymer blend was fabricated. The structure of the device is indium tin oxide/poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate)/emission layer/1,3,5-tris(N-phenylbenzimidazol-2-yl)-benzene/Ba/Al, and the emission layer is a blend of poly［2,7-(9,9-dioctyl)fluorene-co-2,3-bis(4-phenyl)-6-fluoroquinoxaline］ (PF-BPFQ5), phenyl-substituted poly(p-phenylene vinylene) derivative (P-PPV) and poly［2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene］ (MEH-PPV), which, respectively, emits blue, green and red light. When the blend weight ratio of PF-BPFQ5∶P-PPV∶MEH-PPV is 100∶06∶06, a pure white light emission is obtained with CIE coordinates of (0331,0329). The maximal luminance efficiencies is 564 cd/A. Meanwhile, the electroluminescence spectrum of white-light emission is stable under different current densities.
Electronic structure and magnetism of SrFeAsF and Co-doped superconductor SrFe0.875Co0.125AsF
Authors: Liu Su  , Li Bin  , Wang Wei  , Wang Jun  , Liu Mei  ,   东南大学物理系，南京  211198
Published: December 2020

Using the full-potential linearized augmented plane wave method, we studied the electronic structure and magnetic properties of SrFeAsF and Co-doped superconductor SrFe0.875Co0.125AsF. It is found that SrFeAsF exhibits a stripe antiferromagnetic ground state, and in SrFe0.875Co0.125AsF the checkboard antiferromagnetic state become a competitive candidate. The Co-doping drastically suppresses the antiferromagnetic order, increases the density of states near the Femi level and enhances the itineranly of 3d electrons. These results show that the superconductivity is induced by the magnetic fluctuations in SrFe0.875Co0.125AsF.
Formation rule of β-FeSi2 phases in (Fe, M)Si2 ternary alloys
Authors: Li Sheng-Bin  , Li Xiao-Na  , Dong Chuang  , Jiang Xin  ,   大连理工大学材料科学与工程学院，三束材料改性教育部重点实验室，大连 116024
Published: December 2020

Binary β-FeSi2 phase is an important semiconductor metal silicide with narrow band-gaps. The formation of this phase in ternary alloys was investigated for the search of ternary semiconductor silicides. Using the cluster line approach as the theoretical guideline, a structure model is established with one cluster and one glue atom, and alloy series of Fe3Si8M(M=B, Cr, Ni, Cu, Co, Al) were designed by replacing the glue atom Fe in binary β-FeSi2. To obtain homogenous alloys, high vacuum suction casting and melt spinning method were used for the preparation of alloy rods and ribbons. Microstructure and composition analysis showed that the β phase could dissolve 15%—20% Ni, 4%—13% Cu, 7%—10%Co and 7%—10%Cr (molar content). However, in contrary to the designed formula, the added Al replaces Si rather than Fe. There were trace amounts of amorphous particles in Fe3Si8B and Fe3Si8Cr ribbon samples, which showed under the rapid cooling conditions, the addition of B and Cr was favorable for the amorphous phase formation.
Tuning effect of magnetic-field in organic light emitting diodes using LiF layer
Authors: Liu Rong  , Zhang Yong  , Lei Yan-Lian  , Chen Ping  , Zhang Qiao-Ming  , Xiong Zu-Hong  ,   西南大学物理科学与技术学院，重庆  400715
Published: December 2020

The organic light emitting diode with inserted LiF layer has been fabricated. Tris-(8-hydroxyquinoline) aluminum (Alq3) was used as electron-transport layer and N, N′-bis(1-naphthyl)-1,1′-biphenyl-4,4′-diamine (NPB) was used as hole-transport layer. By changing the thickness of LiF deposited between Alq3 and NPB, the optoelectrical properties and the magnetic field effect on electroluminescence were studied at different temperatures. The measurement results show that using LiF layer enables the transport of carrier and the formation of excited states inside the device. A thick LiF layer blocks the transport of holes, lowering the efficiency of the device. However, use of LiF layer can effectively tune the magnetic field effect of electroluminescence. Compared with conventional devices, the magnetic field effect of device with inserted LiF layer was strengthened within low-field range (the magnetic induction BB≥40 mT) decrease of electroluminescence, and the thicker the LiF layer, the smaller the magnitude of decrease. These observations indicate that the concentration of the triplet excitons offects the high magnetic field decrease of electroluminescence at low temperatures.
Research on the optimal thickness of transmission-mode exponential-doping GaAs photocathode
Authors: Yang Zhi  , Zou Ji-Jun  , Chang Ben-Kang  ,   南京理工大学电子工程与光电技术学院，南京  210094
Published: December 2020

The difference between the diffusion drift length of photoelectrons in exponential-doping GaAs photocathode and that in uniform-doping GaAs photocathode is studied. According to quantum equations, the optimized thickness of transmission-mode exponential-doping GaAs photocathode is simulated to be 20 μm. Two transmission-mode exponential-doping GaAs samples with the thickness of 16 and 20 μm are activated by (Cs,O) alternation technique. Integral sensitivities of the two samples are 1228 and 1547 μA/lm, respectively. The ratio of integral sensitivities of the two samples is 0796∶1, which agrees with the simulation result.
Tunneling radiation of particles with electrical and magnetic charges
Authors: Zhou Liang  , Zhang Jing-Yi  ,   广州大学天体物理中心，广州 510006
Published: December 2020

In the Parikh-Wilczeks semiclassical tunneling framework, the Hawking radiation of particles with electrical and magnetic charges tunneling across the event horizon of black hole is investigated. Taking the Reissner-Nordstrǒm black hole with topological defects and with magnetic charges for an example, the calculation shows that the tunneling process of the outgoing particle is consistent with an underlying unitary theory, and supports Parikh-Wilczeks conclusion. The emission spectrum is no longer precisely thermal.
New exact infinite sequence solutions to generalized Boussinesq equation
Authors: Taogetusang  , Sirendaoerji  ,   College of Mathematical Science, Inner Mongolia Normal University, Huhhot 010022, China
Published: December 2020

Based on the auxiliary equation method, the nonlinear superposition formula for the solutions of the second kind of elliptic equation is proposed. It is also used to construct the infinite sequence of new exact solutions to the generalized Boussinesq equation with the aid of symbolic computation system Mathematica. The infinite sequences of exact solutions include the Jacobi elliptic function infinite sequence solutions, the solitary wave infinite sequence solutions and the triangular function infinite sequence solutions. And the method is of significance to seek infinite sequence exact solutions to other nonlinear evolution equations.
Optimized design of filter-fluorescer spectrometer
Authors: Wang Dong  ,   中国工程物理研究院核物理与化学研究所，绵阳  621900
Published: December 2020

The filter-fluorescer method is an important X-ray diagnostic technique. For 14×107—16×107 K blackbody radiation, a four channel spectrometer consisting of filter-fluorescer combinations of V-Ti, Co-Fe, Cu-Ni and Zn-Cu was designed, and the corresponding supplementary channels were supplied for each primary channel. The calculation results show that the measurement of supplementary channel which has the same configuration as that of primary is not accurate, the postfilters of supplementary channels should be reconfigured to make an proper background measurement.
Sudden death and revival of entanglement in two V-type three-level atoms
Authors: Wei Qiao  , Yan Yan  , Li Gao-Xiang  ,   (1)College of Physical Science and Technology , Huazhong Normal University, Wuhan 430079, China; (2)College of Physical Science and Technology , Huazhong Normal University, Wuhan 430079, China;School of Science, Wuhan Institute of Technology, Wuha 430073, China
Published: December 2020

We have studied the sudden death and revival of entanglement in two V-type three-level atoms coupled to the common vacuum. results show that in the case of largely separated atoms, spontaneous emission leads to decoherence and even causes entanglement sudden death. However, the excited-state decay rate of the atom can affect the time of entanglement sudden death. In the case of closely separated atoms, due to the collective effect of atoms, the entanglement which has been dead will revive in some time. The initial entanglement and the revival of entanglement arise from different causes.
Internal ratchet
Authors: Lü Yan  , Wang Hai-Yan  , Bao Jing-Dong  ,   Department of Physics, Beijing Normal University, Beijing 100875, China
Published: December 2020

An internal ratchet model is established, in which a force-free system is coupled to a subsystem with asymmetric periodic structure, while the latter is in a thermal bath environment. The average velocities of particles driven by a periodic signal in two ways are calculated respectively. In comparison with the result of external ratchet with the same parameters, our results show that the maximum directional current of particles in internal ratchet is larger than that in external ratchet. Under the same temperature, the particles in the internal ratchet are more prone to directional movement.
Theoretical analysis and experimental study of the space-charge-screening effect in uni-traveling-carrier photodiode
Authors: Guo Jian-Chuan  , Zuo Yu-Hua  , Zhang Yun  , Zhang Ling-Zi  , Cheng Bu-Wen  , Wang Qi-Ming  ,   State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductor,Chinese Academy of Sciences, Beijing 100086, China
Published: December 2020

A new optimized structure of an UTC (uni-traveling-carrier) photodiode is developed and epitaxied by metal-organic chemical vapor deposition. We fabricated a UTC photodiode of 30 μm in diameter. Theoretical simulation based on drift-diffusion model was used to analyze the space-charge-screening effect in UTC photodiode primarily in two aspects: the carrier concentrations and the space electric field. The simulation results were generally in agreement with the experimental data.
Quantitative analysis of element concentration in Al alloy by using laser-induced breakdown spectroscopy
Authors: Sun Dui-Xiong  , Su Mao-Gen  , Dong Chen-Zhong  , Wang Xiang-Li  , Zhang Da-Cheng  , Ma Xin-Wen  ,   (1)College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China; (2)Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China
Published: December 2020

Laser-induced breakdown plasma is produced by using Q-switched Nd: YAG laser operating at 532 nm, which interacts with the Al alloy sample target in air. The spectral lines in the 230—440 nm wavelength range have been identified, and based on the calibration-free method, the mass concentration of Al alloy are obtained, which is in good agreement with the standard value of the sample.
The full vibrational spectra and dissociation energies of Li2 molecule
Authors: Fan Qun-Chao  , Sun Wei-Guo  , Li Hui-Dong  , Feng Hao  ,   (1)Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China; (2)Research Center for Advanced Computation, School of Physics and Chemistry, Xihua University, Chengdu 610039, China; (3)Research Center for Advanced Computation, School of Physics and Chemistry, Xihua University, Chengdu 610039, China; Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, China
Published: December 2020

Based on the algebraic method (AM) proposed to calculate accurate full vibrational energies for diatomic molecules in Sun’s previous work, the parameter-free analytical formula for dissociation energy of diatomic system is used to study the dissociation energies and the full vibrational spectra of 5 electronic states of Li2 molecule in this work. The results show that the AM vibrational spectra and dissociation energies are in excellent agreement with experimental results.
Beam-wave interaction analysis of gyrotron-traveling-wave tube based on a lossy dielectric-lined waveguide
Authors: Du Chao-Hai  , Liu Pu-Kun  , Xue Qian-Zhong  ,   (1)Key Laboratory of High Power Microwave Sources and Technologies, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China; (2)Key Laboratory of High Power Microwave Sources and Technologies, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China; Graduate University of Chinese Academy of Sciences, Beijing 100049, China
Published: December 2020

A lossy ceramic-loaded waveguide is positive to promote the stability and performance of the gyrotron traveling-wave amplifier (gyro-TWT). In this paper we develop the electron cyclotron maser linear theory on the basis of the field expressions in the lossy ceramic-loaded waveguide. By systematic numerical calculation, we find that both the field patterns and the dispersion curves have one-to-one mapping relation between the modes in ceramic-loaded waveguide and that in empty cylindrical waveguide. With the Laplace transform, the linear theory could calculate the field profile and the threshold of an absolute instability oscillation. The linear theory is also used to study the influence of the magnetic, current and ceramic layer on the amplification characteristics. These results are promotive to the application of the lossy ceramic in a gyro-TWT and the development of the high stable gyro-TWT.
Nonclassicality and decoherence of generalized squeezed Fock state
Authors: Xu Xue-Xiang  , Yuan Hong-Chun  , Hu Li-Yun  ,   (1)College of Physics and Communication Electronics, Jiangxi Normal University, Nanchang 330022, China; (2)College of Physics and Communication Electronics, Jiangxi Normal University, Nanchang 330022, China; Department of Physics, Shanghai Jiao Tong University, Shanghai 200030, China; (3)Department of Physics, Shanghai Jiao Tong University, Shanghai 200030, China
Published: December 2020

We study the nonclassicality and decoherence in photon-loss channel of generalized squeezed Fock state, which is related to the squeezed operator with three real parameters. By using the Weyl ordering invariance under similarity transformations and the technique of integration within an ordered product of operators, we obtain the compact Wigner function of the generalized squeezed Fock state (Laguree-Gaussian function). According to the integration formula of the time evolution of the Wigner function, the Wigner expresssion in photon-loss channel is analytically deduced. In particular, we discussed the nonclassicality from the negativity of the Wigner function.
Optical nonlinearities of excited state intramolecular proton transfer molecule HBT
Authors: Zheng Jia-Jin  , Lu Yun-Qing  , Li Pei-Li  ,   Institute of Optical Communication, College of Optoelectronics Engineering, Nanjing University of Posts and Telecommunications, Nanjing 210003, China
Published: December 2020

The optical nonlinearity, including the nonlinear absorption, the nonlinear refraction and the third-order nonlinear polarizability of 2-(2'-hydroxyphenyl)benzothiazole (HBT) in cyclohexane, has been investigated using a single-beam Z-scan technique. The experiment and calculations show that HBT molecules have obvious two-photon absorption (TPA) effect under the 532 nm picosecond pulsed laser irradiation. The values of the TPA coefficient β0 for different pulse irradiance and the corresponding imaginary part χ(3)I of the third-order nonlinear polarizability were determined according to the open-aperture Z-scan results. Then we measured the nonlinear refractive index γ and the real part χ(3)R of the third-order nonlinear polarizability of HBT, and calculated these two nonlinear parameters with "Gaussian decomposition" method according to the close-aperture Z-scan and open-aperture Z-scan results, when the nonlinear refraction was accompanied by nonlinear absorption. The theoretical results agree very well with the experimental results. This work provides a theoretical as well as a experimental basis for further research and development of the application of the material.
Variational analysis of dipole soliton in nonlocal nonlinear Kerr media
Authors: Yang Zhen-Jun  , Li Shao-Hua  , Lu Da-Quan  , Hu Wei  ,   Key Laboratory of Photonic Information Technology of Guangdong Province, South China Normal University, Guangzhou 510631, China
Published: December 2020

By applying the variational method, we studied a kind of dipole soliton in the nonlocal nonlinear Kerr media. The parameter coupling equations of the dipole soliton were obtained, and numerical simulations were carried out. The results show that the transverse intensity distribution of the dipole soliton is similar to Hermite-Gaussian shape under the condition that the dipole soliton has a high energy which approaches the case of strongly nonlocal nonlinearity. There is a platform between the two intensity peaks of the dipole soltion under the condition that the dipole soliton has a low energy which belongs to the case of weakly nonlocal nonlinearity.
Acoustic holography method for measuring moving sound source with correction for Doppler effect in time-domain
Authors: Yang Dian-Ge  , Luo Yu-Gong  , Li Bing  , Li Ke-Qiang  , Lian Xiao-Min  ,   State Key Laboratory of Automotive Safety and Energy, Department of Automotive Engineering, Tsinghua University, Beijing 100084, China
Published: December 2020

The conventional acoustic holography method is not suitable for the measurement of the moving sound source, because the Doppler effect exists in the sound signal, and the beam-forming approach is unable to make quantitative analysis. The approach proposed in this paper establishes the time-space relation between the measurement field, the radiating field and the acoustic holography field, and puts forward a method of nonlinear time-mapping between the sound source and the measured signal. Based on the acoustic source eigen-function, the acoustic pressure distribution of the acoustic holography field in the time domain is obtained, in which the Doppler effect is eliminated. The sound field of the surface of the moving sound source is reconstructed by acoustic holography method, and the quantitative analysis of the major sound source is realized. This method has been used in the experiment of measuring the moving sound sources, and satisfactory results proved the effectiveness of the method.
Structural characterization of Mn doped SiC magnetic thin films
Authors: Tang Jun  , Liu Zhong-Liang  , Ren Peng  , Yao Tao  , Yan Wen-Sheng  , Xu Peng-Shou  , Wei Shi-Qiang  ,   (1)National Synchrotron Radiation Laboratory, University of Science & Technology of China, Hefei 230029, China; (2)National Synchrotron Radiation Laboratory, University of Science & Technology of China, Hefei 230029, China; School of Physics and Electronic Information, Huaibei Coal Industry Teachers College, Huaibei 235000, China
Published: December 2020

Mn-doped SiC magnetic thin films prepared by co-deposited molecular beam epitaxy (MBE) method on Si (111) substrates at 950 ℃ have been investigated by reflection high energy diffraction (RHEED), X-ray diffraction (XRD) and X-ray absorption near edge structure (XANES) techniques. RHEED results reveal that the SiC thin films doped with Mn are of the cubic structure. XRD and XANES results show that in the thin films with Mn doping concentrations of 0.5％ and 18％ , almost all the Mn atoms react with Si atoms, forming Mn4Si7 compound embedded in the SiC matrix, and no substitutional or interstitial Mn atoms exist in the SiC lattice. Furthermore, we hold that the ferromagnetism of the Mn doped SiC thin films originates mainly from the Mn4Si7 secondary phase.
Numerical study on the evolution of temperature of double-layer target irradiated by high power ion beam
Authors: Wu Di  , Liu Jin-Yuan  , Gong Ye  , Wang Xiao-Gang  , Liu Yue  , Ma Teng-Cai  , Lei Ming-Kai  ,   (1)College of Physical Science and Technology, Dalian University, Dalian 116622, China; (2)Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Dalian 116024, China; (3)Surface Engineering Laboratory, School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China
Published: December 2020

The interaction between high power ion beam and the double-layer target system consisting of Ti film and Al substrate was simulated by TRIM Code. The evolution of energy distribution in the double-layer target irradiated by high power ion beam (HPIB) was obtained. Using the deposited energy in the target as the thermal source term in the nonlinear thermal conduction equations, finite differential method was used to solve the equations. And one-dimensional spatial and temporal evolution of the temperature of the Ti/Al double-layer target irradiated by HPIB during a pulse was obtained. The effect of the ion beam current density on the phase state of the film substrate interface was analyzed. The results show that both Ti and Al are melted at the interface when the ion beam current density is between 100 and 200 A·cm-2.
Band structure of Si-based superlattices Si1-xSnx/Si
Authors: Lü Tie-Yu  , Chen Jie  , Huang Mei-Chun  ,   Department of Physics, Xiamen University, Xiamen 361005, China
Published: December 2020

The prospects of Si-based optical emitting materials are optimistic because the materials are compatible with silicon microelectronics technology. Therefore, many experimental and theoretical studies are directed to the design of direct band-gap Si-based materials. Based on the core state effect, the electronegativity differences effect of component atoms and the symmetry effect, Si-based superlattices Si1－xSnx/Si were designed. We found that Si0.875Sn0.125/Si is a direct band-gap material. In the density functional theory frame, the results of plane pesupotential method show that Si0.875Sn0.125/Si is a direct band-gap superlattice with minimum band-gap at Γ point. We predict that the band gap of the material is 0.96 eV with the help of GW approximation method.