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1.
We reveal that for a realistic system, interference effects are obtained such as the suppression of central line and inner sidebands and the narrowing of the outer fluorescence sidebands. For this purpose, we consider a spontaneous decay from an excited state to a metastable state when the excited and metastable states are resonantly coupled to an auxiliary metastable state by a laser field and a microwave field, respectively. The fluorescence spectrum evolves from a five-peaked structure into a doublet of ultrasharp lines as the ratio of the laser field Rabi frequency to the microwave Rabi frequency is decreased. The physical origin is presented in terms of dressed states. 相似文献
2.
C.-Q. Cao C.-G. Yu H. Cao 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(2):279-284
The spontaneous emission of an excited atom is analyzed by quantum stochastic trajectory approach without both rotating-wave
approximation and Markovian approximation. The atom finite size effect is also taken into account. We show by an example that
the correction due to the counter-rotating wave term is rather small, even for the largest atomic number of real nuclei.
Received 10 July 2002 / Received in final form 12 November 2002 Published online 4 February 2003 相似文献
3.
J. P. Xu Y. P. Yang N. H. Liu S. Y. Zhu 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(2):403-411
Inserting left-handed material (LHM) layers into a one dimensional structure
can influence the spontaneous emission (SpE) of a two-level atom. This has
been investigated, starting from the simplest case of a three-layer
system, where we find the reflected field (atom can “see”) passing through
LHM layer is stronger than that through the corresponding normal layer.
Indeed the induced decay is more strongly influenced by reflected field
passing through LHM layer.
Based on this and after further analysis of reflectivity, we find that, a
quarter photonic crystal (PC) composed of alternately LHM and RHM can
inhibit the atomic spontaneous emission more intensely compared to an
ordinary PC. 相似文献
4.
S. Yuan J.-Y. Gao 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,11(2):267-272
A new scheme of the influence of quantum interference on the spontaneous emission in a coherently driven three-level medium
is presented in this paper. The results are the same with that discussed by [S.-Y. Zhu, L.M. Narducci, M.O. Scully, Phys.
Rev. A 52, 4791 (1995)] under resonance conditions, but they are different when the driven field is detuned.
Received 8 September 1999 and Received in final form 13 January 2000 相似文献
5.
V.I. Yukalov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,13(1):83-91
An ensemble of resonance atoms is considered, which are doped into a medium with well developed polariton effect, when in
the spectrum of polariton states there is a band gap. If an atom with a resonance frequency inside the polariton gap is placed
into the medium, the atomic spontaneous emission is suppressed. However, a system of resonance atoms inside the polariton
gap can radiate when their coherent interaction is sufficiently strong. Thus the suppression of spontaneous emission for a
single atom can be overcome by a collective of atoms radiating coherently. Conditions when such collective effects can appear
and their dynamics are analysed.
Received 7 June 2000 相似文献
6.
We study the effects of quantum interference in the spontaneous emission spectrum of a four-level driven atomic system. We use three strong laser fields to drive the atom and a weak laser field to prepare the initial state of the atom. The atomic system exhibits Autler-Townes triplet in the spectrum. The single Lorentzian peak splits into triplet and their widths are controlled by the relative strengths of the laser fields. 相似文献
7.
Jun Xu Qian Li Wen-chao Yan Xiang-dong Chen Xiang-ming Hu 《Physics letters. A》2008,372(38):6032-6036
We show that it is possible to localize a two-level atom in a half-wavelength region by using a trichromatic field to drive the atom. Of the trichromatic components, one sideband is a standing-wave field with position-dependent amplitude. By varying the sum of relative phases of the sidebands of the trichromatic field to the central component, the atom is localized in either of the two half-wavelength regions with 50% detecting probability when the spontaneously emitted photons are detected. 相似文献
8.
S. Y. Xie Y. P. Yang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(1):163-177
We investigate the spontaneous radiation from a ladder three-level atom
embedded in a three-dimensional anisotropic photonic crystal with an
external driving field. The properties of the spontaneous emission are
dependent strongly on the relative position of the middle level from the
band edge. Due to the Autler-Townes splitting by the action of the driving
field, the external driving field can also affect the properties of the
spontaneous emission. The population exchanged between the upper and the
middle levels decreases as the detuning of the external driving field
frequency from the corresponding transition frequency increases. The
properties of the emission field can be changed or so much as controlled by
choosing suitable intensity of the external driving field. The emission
spectrum is more complex, and dependent on the location of the observer in
this case. 相似文献
9.
W.-H. Sun S.-D. Du X.-S. Chen 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,38(2):397-404
We investigate the phase probability distribution (PPD) of a single-mode
micromaser pumped by atoms injected in the most general case, i.e. in the
superposition of the upper, intermediate and lower states by the Monte
Carlo wave function approach. The phase properties of the cavity mode are
greatly influenced by the relative phases and the amplitudes of the
polarized atoms, and the detunings between the atom and cavity. The cavity
field has a single preferred phase if the cavity is pumped by the atoms in
the superposition of the upper and intermediate states or of the
intermediate and lower states. However, a double-peak feature appears in the
PPD of the cavity field when the cavity is pumped by the atoms in the
superposition of the upper and lower states. With appropriate detunings, the
double peaks become narrower and more remarkable, which shows the better
defined phase of the cavity field, as compared to the resonant case. The PPD
displays complicated characteristics when the cavity is pumped by the atoms
in the superposition of the upper, intermediate and lower states. The phase
distribution changes from a single peak to double peaks and to another
single peak when we modulate the phase of the intermediate state, which has
been explained in the semi-classical radiation theory. 相似文献
10.
We study the coherent control of spontaneous emission of a double-driven four-level atom embedded in photonic crystals. Combined effect of different relative locations between the upper band edge and the two upper levels and the phase of microwave coupling field is discussed. It is shown that quantum interference effect such as laser-induced dark line depends strongly on the phase of microwave field. 相似文献
11.
We have studied the spontaneous emission behaviour in a five-level M-type atom driven by two optical fields of high frequencies and a microwave field of low-frequency. In absence of non-orthogonal decaying pathways, due to microwave field induced low-frequency coherence, the present model produces the emission spectrum resembling that of a three-level system controlled by the effect of vacuum induced decay-interference. For particular sets of values of the Rabi frequencies of the resonant coherent fields, the system exhibits quantum interference induced switching effect. By using this model, we have shown that the phenomenon of narrowing can be induced in the emission peaks without any detuning and phase control of the coherent fields. With the increase in the value of the Rabi frequency of the microwave field, this feature will be accompanied by the peak-compression and -repulsion effect. When the coherent fields are far from resonance, the appearance of the single-photon and the two-photon peaks in the emission spectrum can be easily controlled by changing the value of the Rabi frequency of the microwave field. We have shown the appearance of multiple dark regions in the emission line shape for equal as well as unequal decay rates of two emission pathways. Other interesting phenomena like elimination, enhancement and suppression of spectral line are also explored in various resonant and non-resonant cases. 相似文献
12.
We propose an optical scheme to generate cluster states of atomic qubits, with each trapped in separate optical cavity, via atom-cavity-laser interaction. The quantum information of each qubit is encoded on the degenerate ground states of the atom, hence the entanglement between them is relatively stable against spontaneous emission. A single-photon source and two classical fields are employed in the present scheme. By controlling the sequence and time of atom-cavity-laser interaction, we show that the atomic cluster states can be produced deterministically. 相似文献
13.
S. Roshan Entezar 《Optics Communications》2009,282(6):1171-1174
In this paper, the effect of quantum interference on the entanglement of a driven V-type three-level atom and its spontaneous emission field was investigated by using the quantum entropy. The results indicate that, in the absence of quantum interference the atom and its spontaneous emission field are always entangled at the steady-state. But, in the presence of full quantum interference their steady-state entanglement depends on the atomic parameters. Specifically, with appropriate atomic parameters they can be entangled or disentangled at the steady-state. We realized that the steady-state entanglement is due to completely destructive nature of quantum interference. On the contrary, the steady-state disentanglement is due to instructive nature of quantum interference. 相似文献
14.
E. Schumacher M. Wilkens P. Meystre S. Glasgow 《Applied physics. B, Lasers and optics》1992,54(5):451-466
We study the influence of spontaneous emission on atom diffraction by a standing wave laser field. We characterize, analytically, the major regimes of the near-resonant Kapitza-Dirac effect and study, numerically, the influence of spontaneous emission. In particular, we discuss in some detail two important classes of two-beam resonances which are major candidates to develop effective atom beam splitters, the so-called Bragg and Doppleron resonances. 相似文献
15.
G. H. Yang L. Zhou 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,47(2):277-282
We investigate two identical Λ-type atoms in free space, and focus
on the entanglement between the two atoms. We derive a master equation for
the atomic subspace and solve it analytically to show how the spontaneous
emission from the two atoms system induces entanglement. The magnitude of
the entanglement and the steady state entanglement are found to be strongly
dependent on the initial states and the orientation of the dipoles of the
two atoms. 相似文献
16.
Ground State of Jaynes-Cummings Model: Comparison of Solutions with and without the Rotating-Wave Approximation 下载免费PDF全文
The eigenenergy spectrum of the Jaynes-Cummings (JC) model with and without the rotating-wave approx- imation (RWA) is investigated. The numerical analysis indicates that the non-RWA spectrum can only be approximated by the RWA in the range of sufficiently small coupling constant and detuning. In other region, the counter-rotating terms remarkably change the nature of the RWA energy spectrum. A simple expression with high accuracy for ground eigenenergy and eigenvector non-RWA shows that the ground state is not a dark state state. for non-RWA is available. The ground eigenvector for and very different from that of RWA which is a dark state. 相似文献
17.
Xiang-ming Hu Qing Xu Jing-yan Li Xiao-xia Li Wen-xing Shi Xiu Zhang 《Optics Communications》2006,260(1):196-202
Bichromatic and trichromatic manipulation of spontaneous emission in a three-level system in Λ configuration is studied on the basis of density matrix equation and quantum regression theorem. The spontaneous emission spectrum is numerically calculated by using harmonic expansion and matrix inversion. Two characteristic features are shown. Firstly, the central resonance peak, which is absent in the case of monochromatic excitation, is recovered for the bichromatic or trichromatic excitation. Secondly, selective elimination of the spectral lines is obtained by varying the amplitudes and phases of the trichromatic components. For the phase dependence, it is the sum of the relative phases of the two sideband components to the central component that plays a crucial role. The spontaneous emission spectrum is drastically modified once the sum phase is changed, but is kept unchanged regardless of the respective phases when the sum phase is fixed. 相似文献
18.
Quantum controlled phase gate and cluster states
generation via two superconducting quantum interference devices in a
cavity 总被引:3,自引:0,他引:3
Z.-Y. Xue G. Zhang P. Dong Y.-M. Yi Z.-L. Cao 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,52(3):333-336
A scheme for implementing 2-qubit quantum controlled phase gate (QCPG) is proposed with two superconducting quantum interference
devices (SQUIDs) in a cavity. The gate operations are
realized within the two lower flux states of the SQUIDs by using a quantized cavity field and classical microwave pulses.
Our scheme is achieved without any type of measurement, does not use the cavity mode as the data bus and only requires a very
short resonant interaction of the SQUID-cavity system. As an application of the QCPG operation, we also propose a scheme for
generating the cluster
states of many SQUIDs. 相似文献
19.
We show that the bichromatic phase control of the spontaneous emission spectrum leads to the sub-half-wavelength atom localization. We consider a three-level Λ-type atom interacting with a bichromatic coupling field and a bichromatic probe field with equal frequency difference. One component of the bichromatic coupling field is a standing-wave field with position dependent Rabi frequency. When the spontaneous emitted photons are detected, the atom is localized in either of the two half-wavelength regions with 50% probability by the variation of the difference between the relative phases of the two bichromatic fields. 相似文献
20.
Q. Xu X. M. Hu J. W. Yin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,51(2):267-273
The atomic coherence in a three-level Λ atom is studied, in which each optical transition is driven by a coherent field and
the metastable states are coupled to each other via a microwave field. It’s shown that the atomic coherence crucially depends
on the relative phase delay between the envelopes of the amplitudes of the three coupling fields. In particular, when the
phase delay is adjusted to 0 or π, the maximal atomic coherence arises, while the maximal atomic coherence doesn’t occur once
the phase delay is changed to π/2. The maximal atomic coherence is attributed to the trapping of the population in the lower
sublevels. 相似文献