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1.
A.G. Kofman 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,17(2):153-165
The electromagnetically induced transparency (EIT) with a (near-)resonant chaotic (amplitude-phase fluctuating, Gaussian-Markovian)
coupling field is studied theoretically. The Fourier transform of the steady-state EIT spectrum, which determines a nonstationary
probe absorption, is also considered. This quantity equals the average diagonal element of the (reduced) evolution operator
of the coupled transition (the evolution function). The exact solution in the form of a continued fraction is obtained and
used to perform numerical calculations. Moreover, a number of approximate analytical results are obtained, which, together
with the results of previous publications, describe the EIT and the evolution function in all possible regimes. In particular,
in the constructive-interference case the EIT increases with the coupling-field bandwidth ν at sufficiently small ν. For a strong field, the maximum of the transparency as a function
of ν is less than that for a monochromatic field of the same average intensity. In contrast, for a weak field, there is a
range of ν values, where the field fluctuations do not affect the EIT. The latter result is shown to hold for a broad class of stochastic fields.
Received 31 December 2000 and Received in final form 14 May 2001 相似文献
2.
J.-H. Wu J.-Y. Gao 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(2):315-319
In order to achieve the phase-sensitive probe gain without population inversion, we investigate a three-level Λ-type atomic system driven by a coherent field and a microwave field. It is shown that, by modulating the relative phase of
applied fields, we can obtain quite high inversionless gain at different probe detunings and change the gain behavior of the
probe correspondingly. We find that amplitudes of the coherent field and the microwave field are also important factors that
can result in different gain behavior of the probe. Here, we use the microwave field to induce the quantum coherence between
the two ground levels, which is necessary for phase-sensitive effects, since it can result in the interference between two
different transition channels.
Received 20 June 2002 / Received in final form 5 December 2002 Published online 4 March 2003 相似文献
3.
4.
当两束激光以Λ-构型作用于三能级原子系统并满足双光子共振条件时,探测激光场吸收谱呈现电磁诱导透明(EIT)特征.若再加一个微波控制场作用于该三能级系统的两个低能级跃迁之间,会导致探测吸收特性明显变化,EIT窗口将发生劈裂.通过求解相应的密度矩阵方程,揭示了外加微波场作用下EIT窗口的变化规律,并给出了相应的缀饰态解释.研究结果表明,在适当的条件下, 电磁诱导透明呈现三重结构,而EIT窗口的频率位置取决于微波控制场的拉比频率及频率失谐量.因此通过改变微波控制场的参数可以实现多EIT窗口的频率调谐.
关键词:
电磁诱导透明
量子相干
频率调谐
多窗口EIT 相似文献
5.
It is shown theoretically that electromagnetically induced transparency (EIT) due to strong exciton–phonon coupling can occur
in strongly coupled exciton–phonon systems such as polymers and organic semiconductors and lead to ultra-slow light effects.
The results indicate that the strong coupling of excitons and phonons is important, but the exciton– exciton interaction plays
a small role in the generation of the EIT. Numerical results for polydiacetylene–toluene sulfonate are also presented. This
EIT in a solid-state medium might be utilized for efficient multiwave mixing and quantum nondemolition measurements, as well
as for novel acousto-optical devices.
Received: 21 August 2002 / Published online: 20 December 2002
RID="*"
ID="*"Corresponding author. E-mail: zhukadi@yahoo.com 相似文献
6.
电磁感应透明的重要参量之一是透明窗口的光谱线宽。在Λ-型三能级原子系统中,电磁感应透明的光谱线宽由两低能级间的相干失相速率决定,若两低能级同属于原子基态的精细结构,则电磁感应透明窗口的极限线宽很窄。但较强的耦合场作用往往会导致电磁感应透明窗口的功率展宽,而减弱耦合场又会影响电磁感应透明的对比度和深度。为此,通过引入微波控制场共振作用于基态精细能级间构成三场作用下的准Λ-型四能级系统,利用微波控制场来抑制耦合场所引起的电磁感应透明窗口的功率展宽。结果表明,引入微波控制场不仅得到了双窗口电磁感应透明,而且在保持较好对比度的条件下,使得电磁感应透明的光谱线宽明显小于不加微波场的情况。 相似文献
7.
A. Sargsyan C. Leroy Y. Pashayan-Leroy R. Mirzoyan A. Papoyan D. Sarkisyan 《Applied physics. B, Lasers and optics》2011,105(4):767-774
The electromagnetically induced transparency (EIT) on the atomic D
1 line of rubidium is studied using a nanometric-thin cell with atomic vapor column length in the range of L=400–800 nm. It is shown that the reduction of the cell thickness by four orders as compared with an ordinary cm-size cell
still allows to form an EIT resonance for L=λ=794 nm with the contrast of up to 40%. Further reduction of thickness to L=λ/2 leads to significant reduction of EIT contrast, verifying that the key parameter for EIT in wavelength-scale-thickness
cells is not the value of L itself but L/λ ratio. Remarkable distinctions of EIT formation in nanometric-thin and ordinary cells are demonstrated. Well-resolved splitting
of the EIT resonance in a magnetic field for L=λ can be used for magnetometry with nanometric spatial resolution. The presented theoretical model well describes the observed
results. 相似文献
8.
Zhuan Li Li-Ping Deng Li-Sen Xu Kaige Wang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,40(1):147-156
We study a four-level double-Λ atomic ensemble interacting with two
time-dependent signal fields and two stationary control fields. Though, in
each Λ channel, a pair of signal and control fields couple
resonantly with the two lower levels of atoms, the occurrences of
electromagnetically induced transparency (EIT) is affected by the coherence
of the four fields. In the discussion of atomic susceptibilities, we show
that the quantum coherence between the two lower levels can be either formed
or released according to the phase matching of the four fields. We analyze
the propagation equation of the two signal fields, and find two
characteristic solutions: the stationary transmission wave and the transient
decay wave. The former corresponds to a correlated EIT effect in which two
signal pulses are shape-matched. The latter is an opposite effect to the
correlated EIT in which two pulses quench simultaneously, thus named as the
correlated two-signal absorption (CTSA). We propose the CTSA condition in
correspondence with the EIT condition. The numerical simulation shows that
the double-Λ configuration is capable of manipulating synchronous
optical signals and thus provides multiplicity and versatility in quantum
information process. 相似文献
9.
We show that nonadiabatic, resonant amplitude- and phase-modulated pulses can be frequency converted with greater efficiency than adiabatic resonant pulses in a double Λ system, interacting with two strong cw beams on one side of the system, and a weak pulsed probe on the other. Indeed, in this double EIT (electromagnetically induced transparency) configuration, conversion efficiencies close to unity, similar to those achieved using highly detuned pulses, can be obtained using highly nonadiabatic resonant pulses. The distance at which the maximum conversion occurs is shorter than in a coherently-prepared Λ system. This counteracts the increased absorption that occurs in the double EIT configuration, so that both produce similar conversion efficiencies. The absorption experienced by matched nonadiabatic pulses in the double EIT system, at all propagation distances, can be overcome by superimposing the nonadiabatic pulses as amplitude modulations on carrier fields. Thus we demonstrate the formation of adiabatons in the double EIT system, and of diabatons in both the coherently-prepared Λ system and the double EIT system. Both the diabatons and adiabatons satisfy pulse-matching conditions. In addition, the asymptotic amplitude of the complementary amplitude modulations is proportional to the ratio of the pump to probe carrier Rabi frequencies, and is the same in each of the configurations. 相似文献
10.
主要研究了室温下微波场缀饰的铯Rydberg原子的电磁感应透明-Autler-Townes(EIT-AT)光谱.首先,以铯原子6S_(1/2)→6P_(3/2)→50S_(1/2)形成阶梯型三能级系统,利用强耦合光作用于6P_(3/2)→50S_(1/2)的Rydberg跃迁,弱探测光耦合基态跃迁6S_(1/2)→6P_(3/2)并探测由耦合光形成的电磁感应透明(EIT)效应.然后,以频率为30.582 GHz的微波电场耦合相邻的Rydberg能级50S_(1/2)→50P_(1/2)产生微波AT分裂.利用Rydberg EIT探测微波耦合相邻Rydberg能级产生的AT分裂,形成EIT-AT光谱,进而实现微波电场的测量.当微波场的强度增加到一定值时,EIT-AT光谱表现为多峰光谱结构.分析EIT-AT多峰光谱的成因,发现这主要是由场的不均匀性导致的,一定的EIT-AT光谱特征对应于特定的非均匀场分布.研究表明,利用Rydberg EIT-AT光谱可以实现微波电场的测量,利用其光谱特征可实现微波场的实时监测,进而提出了一种提高微波场空间分辨率的测量方法. 相似文献
11.
R.K. Varma 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(2):211-218
It has been shown earlier [3,6] that matter waves which are known to lie typically in the range of a few angstrom, can also
manifest in the macrodomain with a wave length of a few centimeters, for electrons propagating along a magnetic field. This
followed from the predictions of a probability amplitude theory by the author [1,2] in the classical macrodomain of the dynamics
of charged particles in a magnetic field. It is shown in this paper that this case constitutes only a special case of a generic
situation whereby composite systems such as atoms and molecules in their highly excited internal states, can exhibit matter
wave manifestation in macro and mesodomains, in one-dimensional scattering. The wave length of these waves is determined,
not by the mass of the particle as in the case of the de Broglie wave, but by the frequency ω, of the classical orbital motion
of the internal state in the correspondence limit, and is given by a nonquantal expression, λ = 2πv/ω, v being the velocity of the particle. For the electrons in a magnetic field the frequency corresponds to the gyrofrequency,
Ω and the nonquantal wave length is given by λ = 2πv
|| /Ω; v
|| being the velocity of electrons along the magnetic field.
Received 29 September 2001 / Received in final form 23 May 2002 Published online 19 July 2002 相似文献
12.
L. S. Cruz D. Felinto J.G. Aguirre Gómez M. Martinelli P. Valente A. Lezama P. Nussenzveig 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(3):531-539
High degrees of intensity correlation between two independent lasers were
observed after propagation through a rubidium vapor cell in which they generate
Electromagnetically Induced Transparency (EIT). As the optical field intensities are
increased, the correlation changes sign (becoming anti-correlation). The experiment was
performed in a room temperature rubidium cell, using two diode lasers tuned to the
85Rb D2 line (λ= 780 nm). The cross-correlation spectral function for the
pump and probe fields is numerically obtained by modeling the temporal dynamics of both
field phases as diffusing processes. We explored the dependence of the atomic response on
the atom-field Rabi frequencies, optical detuning and Doppler width. The results show
that resonant phase-noise to amplitude-noise conversion is at the origin of the observed
signal and the change in sign for the correlation coefficient can be explained as a
consequence of the competition between EIT and Raman resonance processes. 相似文献
13.
R.J. Tarento P. Joyes J. van de Walle 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,13(3):355-360
The present study focuses on electronic correlation effects on magnetic energy, the spin-spin correlation function of an octahedron
cluster in the (3↑, 3 ↓) electronic configuration threaded by a magnetic field. Some other spin configurations are also discussed
and various field directions are considered. An accurate diagonalisation technique has been used to solve the Hubbard Hamiltonian.
A result is analysed on a linear energy stabilisation at low magnetic flux. Moreover, two types of antiferromagnetic transition
versus the flux occurring for a correlation term larger than a critical one have been observed, i.e. the likelihood of a charge excitation before the antiferromagnetic transition. Finally, a comparison between the results
obtained from the exact diagonalisation and the Gutzwiller method has been carried out, leading to a suggested modification
of the Gutzwiller approach in order to improve it.
Received 23 June 1999 and Received in final form 28 July 2000 相似文献
14.
J. Alnis M. Auzinsh 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,11(1):91-97
The paper presents a discussion on the problem of alignment-orientation conversion in an excited state of molecules. It is
shown that a rather strong alignment-orientation conversion effect in the excited molecular state can be caused by a joint
action of an external magnetic field and hyperfine interaction. The orientation thus created is transverse, i.e. perpendicular to the direction of the external magnetic field. The magnitude of this effect is analyzed as dependent on molecular
parameters.
Received 15 July 1999 and Received in final form 17 November 1999 相似文献
15.
M. Fifirig A. Cionga 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,15(1):33-39
We study the “coherent phase control” between the three-photon ionization by a fundamental laser field and the one-photon
ionization by its third harmonic for a hydrogen atom in its ground state. The relative phase δ of the harmonic field with
respect to the fundamental laser radiation “modulates” the interference between the two ionization channels, which is important
near the crossing points between the ionization rates of the two individual processes. Numerical results for the total ionization
rate and for the angular distribution of the photoelectrons as a function of the phase δ are presented for frequencies located
in the vicinity of the atomic resonances corresponding to the absorption of two laser photons.
Received 31 August 2000 and Received in final form 6 February 2001 相似文献
16.
L. Li G. X. Huang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,58(3):339-348
We study the modified effect of slow-light soliton in a resonant three-level atomic system via electromagnetically inducedtransparency (EIT) by utilizing a microwave field. We derive ahigh-order nonlinear Schrödinger equation by using a perturbation method of multiple-scales, and calculate the modification ofsoliton velocity and frequency shift. We find that in the presence of the microwave field an obvious decrease of propagating velocityof soliton can be realized, which provides an effective method to slow down optical solitons in EIT systems. We also find that thedown shift of oscillating frequency of soliton in such system can be largely suppressed by the microwave field. 相似文献
17.
The effect of electromagnetically induced transparency (EIT) in a Λ-system formed by rubidium atoms contained in thin (10–60
μm) and extremely thin (0.3–5 μm) cells was studied experimentally. It was found that parameters of the EIT resonance degrade
slowly in the case where the frequency of the coupling laser is in resonance with the D
2 transition of rubidium, which enabled the registration of the EIT resonance in a record thin cell with a thickness of L = 390 nm. The specific features of EIT in extremely thin cells reveal themselves when the coupling laser has a frequency
detuning Δ from the atomic transition. In this case, the width of the EIT resonance rapidly increases upon an increase in
Δ at fixed L (an opposite effect takes place in centimeter-scale cells). It is shown that the width of the EIT resonance is inversely
proportional to L in the case of fixed large detuning Δ. The nearly tenfold broadening of the EIT resonance for large values of detuning Δ
is caused by the influence of atomic collisions with cell windows on dephasing rate of coherence. The expressions that allow
the estimation of the EIT-resonance width for various values of detuning Δ and small values of thickness L are found. 相似文献
18.
M. Kajita A. V. Avdeenkov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(3):499-504
The collisions between linear polar molecules, trapped in
a microwave field with circular polarization, are theoretically
analyzed. We demonstrate that the collisional dynamics is mostly
controlled by two ratios ν/B and x=μ0E0/ħ
B (ν is the microwave frequency, B is the molecular
rotational constant, μ0 is the dipole moment, and E0 is
the electric field amplitude). We discuss the dependence of collision
cross sections on these ratios in order to find an advantageous
condition for evaporative cooling. 相似文献
19.
V. B. Braginsky M. L. Gorodetsky F. Y. Khalily 《Applied physics. B, Lasers and optics》1997,64(2):243-247
We propose a new scheme of QND measurement in microwave band. It is shown that with deflection of electron beam in the electric
field of a microwave resonator it is possible to measure quadrature amplitude of oscillations with the precision substantially
exceeding the standard quantum limit. Estimates for the parameters of the experimental setup are presented.
Received: 27 March 1996/Revised version: 5 August 1996 相似文献
20.
N. Andrenacci P. Pieri G.C. Strinati 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,13(4):637-642
We consider a system of fermions in the continuum case at zero temperature, in the strong-coupling limit of a short-range
attraction when composite bosons form as bound-fermion pairs. We examine the density dependence of the size of the composite
bosons at leading order in the density (“dilute limit”), and show on general physical grounds that this size should decrease with increasing density, both in three and two dimensions. We then compare with the analytic zero-temperature mean-field
solution, which indeed exhibits the size shrinking of the composite bosons both in three and two dimensions. We argue, nonetheless,
that the two-dimensional mean-field solution is not consistent with our general result in the “dilute limit”, to the extent
that mean field treats the scattering between composite bosons in the Born approximation which is known to break down at low
energy in two dimensions.
Received 3 June 1999 and Received in final form 29 July 1999 相似文献