期刊：
Journal of Modern Optics,2001年48(7):1255-1268 ISSN：0950-0340
作者机构：
[Guo Hong; Peng Jin-Sheng] Department of Physics , Huazhong Normal University , Wuhan, 430079 E-mail: GuoHong@phy.ccnu.edu.cn
摘要：
Abstract By means of quantum electrodynamics, an analytical expression of emission spectrum for a Λ-type three-level atom with the two non-degenerate lower levels in the cavity is given. The character of the emission spectrum for the input in pure number state, a squeezed coherent state and grey-body state are exhibited. The effects of the atomic initial state, the field property, the cavity absorptivity and the system temperature on the time-dependent physical spectrum are analysed.
作者机构：
[Li, GX] Hong Kong Baptist Univ, Dept Phys, Hong Kong, Hong Kong, Peoples R China.;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.;Xian Jiao Tong Univ, Dept Appl Phys, Xian 710049, Peoples R China.
通讯机构：
[Li, GX] H;Hong Kong Baptist Univ, Dept Phys, Hong Kong, Hong Kong, Peoples R China.
摘要：
Spontaneous emission of an atom with two close upper levels and one lower level in a multilayer dielectric medium, and quantum interference between transitions from the upper levels to the lower one, are considered. Since the medium is inhomogeneous along the direction normal to the interfaces of the dielectric layers, the vacuum has an anisotropic spatial structure, and quantum intereference between the two decay channels can appear even if the two dipole matrix elements are orthogonal to each other. If the atom is placed in a three-layer dielectric plate cavity, a strong quantum interference similar to that for an atom with two nearly parallel dipole moments in free space arises due to the influence of anisotropic vacuum. Putting the atom in a three-layer dielectric waveguide and a one-dimensional photonic crystal, there appears a strong quantum interference similar to that for an atom with nearly antiparallel dipole moments.
摘要：
目前访问Web数据库的技术主要有CGI、ISAPI、JDBC、Plug-jn插件和ASP.ASP是开发动态网站和Web数据库的主要技术之一.
(1)ASP访问数据库的原理:ASP程序由ADO(ActiveX Data Obiect)等内置组件及Request、Server、Response等内建对象构建而成,所有ASP程序都在服务器端执行,包括脚本程序和ASP语法.当浏览器通过HTTP协议向Web服务器申请一个数据传输的请求时,Web服务器首先判断要传输的数据是否为.asp文件,若不是则直接传输;否则用ASP引擎解释被申请文件,若程序的ASP语法部分有访问数据库的请求,Web服务器会根据ADO对象所设置的参数来启动对应的ODBC驱动程序,使其直接利用ADO对象或通过ADO对象发送SQL指令来存取数据库,并将访问的结果返回Web服务器.ASP引擎将运行结果与原有文本和HTML标记一起组成标准HTML页面传给浏览器,由浏览器解释执行.
作者机构：
[Shi Z.-Y.] Department of Physics, Guizhou Institute for Nationalities, Guiyang 550025, China;[Liu Y.] Institute of Particle Physics, Huazhong Normal University, Wuhan 430079, China;[Sang J.-P.] Department of Physics, Wuhan University, Wuhan 430072, China
通讯机构：
[Shi, Z.-Y.] D;Department of Physics, , Guiyang 550025, China
关键词：
High-spin states;Microscopic investigation;sdIBM-2+2q.p model
作者机构：
[Hu, XM] Chinese Acad Sci, Shanghai Inst Opt & Fine Mech, Lab High Intens Opt, Shanghai 201800, Peoples R China.;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Hu, XM] C;Chinese Acad Sci, Shanghai Inst Opt & Fine Mech, Lab High Intens Opt, Shanghai 201800, Peoples R China.
摘要：
An anomalous linewidth is predicted to appear in a driven Mollow laser. The linewidth does not simply decrease as the laser intensity increases, but displays a local minimum and maximum. The maximal linewidth does not necessarily correspond to the maximal population in the excited lasing level but to the minimal population. Employing the dressed picture, we separate the population component of the linewidth from the coherence component. It is identified that quantum coherence is responsible for the linewidth anomaly. We isolate two irreversible pathways of population pumping and show that the coherence effects are ultimately determined by the population pumping through the two irreversible pathways.
作者机构：
[Hu, XM] Chinese Acad Sci, Shanghai Inst Opt & Fine Mech, Lab High Intens Opt, Shanghai 201800, Peoples R China.;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Hu, XM] C;Chinese Acad Sci, Shanghai Inst Opt & Fine Mech, Lab High Intens Opt, Shanghai 201800, Peoples R China.
摘要：
We present phase control of the fluctuation-induced bistability in the three-level Λ-type system where a weak, amplitude-fluctuating component and a strong coherent component are used as a control field. With the addition of the stochastic component, optical bistability can be produced even if detunings of the probe and control fields from corresponding atomic transition frequencies are equal;without the addition, the medium is transparent to the input light. Depending on the relative phase between the stochastic and coherent parts, bistability appears or disappears and the threshold intensity is raised or lowered.
作者机构：
[Hu, XM; Xiong, J; Peng, JS] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Hu, XM] H;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
摘要：
A theoretical analysis of the spectral linewidth of V-type inversionless and Raman lasers is presented. First, we examine the effects of the atomic coherence between dressed states and the Autler-Townes splitting on the linewidth. It is demonstrated that near above threshold, the V inversionless laser has a narrower linewidth than that of the two-level laser. Instead of the dressed coherence, it is the Autler-Townes splitting that is responsible for the linewidth reduction though the dressed coherence determines the laser gain. Next, we explore the effects of the generated laser intensity on the linewidth. It is shown that the linewidths of the V inversionless and Raman lasers follow the usual 1/I decrease for smaller laser intensity I, but a slower decrease than 1/I for larger laser intensity. For the V Raman laser, even more surprisingly, with the laser intensity increasing, the linewidth appreciably increases as well. As a result, well above threshold, the V inversionless and Raman lasers may have a larger linewidth than that of the two-level laser. Finally, a comparison is made between the V lasers and the Λ lasers. It is found that the linewidth of the Λ inversionless laser shows a fast 1/I2 decay under optimum conditions.
作者机构：
[Hu, XM] Chinese Acad Sci, Shanghai Inst Opt & Fine Mech, Lab High Intens Opt, Shanghai 201800, Peoples R China.;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
通讯机构：
[Hu, XM] C;Chinese Acad Sci, Shanghai Inst Opt & Fine Mech, Lab High Intens Opt, Shanghai 201800, Peoples R China.
摘要：
We study the statistical properties of a three-level laser where cascade coherent excitation as a two-step process is used as a coherent pump and a laser field is generated on the upper transition. It is shown that the laser intensity fluctuations are suppressed up to 50% below the shot noise limit and that the laser linewidth is reduced below the Schawlow-Townes formula by more than one order of magnitude of the laser intensity. By transforming to the picture dressed by the coherent field on the upper transition, we identify a transfer of the lower coherent excitation to be responsible for the quantum noise reduction. Cascade coherent excitation turns out to be a new way in which one can create a pathway for recycling of active electrons and regularization of laser excitation process. The conditions for the physical realization of the Raman scheme (Ritsch et al 1992 Europhys. Lett. 19 7) as a limiting case is discussed.
作者机构：
[Li, GX] Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.;Chinese Acad Sci, Wuhan Inst Phys & Math, State Key Lab Magnet Resonance & Atom & Mol Phys, Wuhan 430071, Peoples R China.
通讯机构：
[Li, GX] H;Huazhong Normal Univ, Dept Phys, Wuhan 430079, Peoples R China.
摘要：
The time evolution of nonlocality for atom-field entangled state in the system of a two-level atom interacting dispersively C with a single-mode field in a dissipative cavity is investigated. It is found that, if the cavity dissipation is very weak, the atom-field state can exhibits nonlocality periodically. The rapidity of the loss of the initial quantum nonlocality depends on the amplitude of the two coherent states and the cavity damping constant K. The stronger the field is and the larger the constant K, the more rapidly the nonlocality decreases. (C) 2001 Elsevier Science B.V. All rights reserved.
作者机构：
[Liu, LS] Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.;Jingzhou Teachers Coll, Hubei 434100, Peoples R China.
通讯机构：
[Liu, LS] H;Huazhong Normal Univ, Inst Particle Phys, Wuhan 430079, Peoples R China.
摘要：
A study of the dynamical fluctuation property of jets is carried out using the Monte Carlo method. The results suggest that, unlike the average properties of the hadronic system inside jets, the anisotropy of dynamical fluctuations in these systems changes abruptly with the variation of the cut parameter ycut. A transition point exists, where the dynamical fluctuations in the hadronic system inside jets behave like those in soft hadronic collisions, i.e., being circular in the transverse plane with respect to dynamical fluctuations. This finding obtained from JETSET and HERWIG Monte Carlo programs is encouraged to be checked by experiments.
作者机构：
[Liu, YY] E China Normal Univ, Dept Phys, Key Lab Opt & Magnet Resonance Spect, Shanghai 200062, Peoples R China.;Chinese Acad Sci, Wuhan Inst Phys & Math, State Key Lab Magnet Resonance & Atom & Mol Phys, Wuhan 430071, Peoples R China.;Huazhong Normal Univ, Dept Phys, Wuhan 430070, Peoples R China.
通讯机构：
[Liu, YY] E;E China Normal Univ, Dept Phys, Key Lab Opt & Magnet Resonance Spect, Shanghai 200062, Peoples R China.
摘要：
An intracavity CO laser magnetic resonance spectrometer with homogeneous dc electric field applied via a pair of parallel Stark plates in the absorption cell is used to measure the electric dipole moments of free radicals. Taking advantage of the high sensitivity and high resolution of this technique and the Stark effect, highly-resolved saturated absorption spectra of the v = 1 - 0 transition of 15N16O in the ground state X2Π3/2 have been successfully observed in the presence of a low electric field. The electric dipole moment of NO in the electronic ground state is determined as μ = 0.1566 ± 14D (Debye) from the analysis of the observed spectra, confirming that, combined with the Stark field, the laser magnetic resonance technique can be an effective and reliable approach for the precise measurement of electric dipole moments of free radicals, especially unstable ones.
