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1.
This review discusses the latest theoretical and experimental achievements in the resonant light pressure acting on the translational motion of atoms. Alongside with the effects due to the spontaneous light pressure (atomic deflection, velocity bunching, cooling), various manifestations of the effects of induced light pressure are considered in detail. This paper provides the theory and experiments of atoms scattering by a standing light wave under the conditions of coherent and non-coherent interaction, diffraction and interference of atomic beams. The problems where atomic motion along two trajectories and Landau-Zener transitions between them are essential, are studied. The kinetic phenomena (scattering, cooling, channeling) due to the motion of the particles exposed to gradient force and also friction and diffusion caused by spontaneous emission are considered. The influence of the recoil effect under spontaneous emission of atoms on non-linear polarization phenomena is discussed. 相似文献
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分析了一个运动的三能级原子与一个驻波激光场地斜交相互作用时的动量传递行为。结果表明,当原子和光场由于多普勒效应满足一定条件时,将产生受激拉曼跃迁。如果作用光相对于原子而言为一个“π/2脉冲”光时,那么经过作用后,原子将处于一个相干迭加态,其中一个态与加始相同。 相似文献
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S. V. Prants 《Journal of Experimental and Theoretical Physics》2009,109(5):751-761
A quantum analysis is presented of the motion and internal state of a two-level atom in a strong standing-wave light field. Coherent evolution of the atomic wave-packet, atomic dipole moment, and population inversion strongly depends on the ratio between the detuning from atom-field resonance and a characteristic atomic frequency. In the basis of dressed states, atomic motion is represented as wave-packet motion in two effective optical potentials. At exact resonance, coherent population trapping is observed when an atom with zero momentum is centered at a standing-wave node. When the detuning is comparable to the characteristic atomic frequency, the atom crossing a node may or may not undergo a transition between the potentials with probabilities that are similar in order of magnitude. In this detuning range, atomic wave packets proliferate at the nodes of the standing wave. This phenomenon is interpreted as a quantum manifestation of chaotic transport of classical atoms observed in earlier studies. For a certain detuning range, there exists an interval of initial momentum values such that the atom simultaneously oscillates in an optical potential well and moves as a ballistic particle. This behavior of a wave packet is a quantum analog of a classical random walk of an atom, when it enters and leaves optical potential wells in a seemingly irregular manner and freely moves both ways in a periodic standing light wave. In a far-detuned field, the transition probability between the potentials is low, and adiabatic wave-packet evolution corresponding to regular classical motion of an atom is observed. 相似文献
5.
V.G. Minogin 《Optics Communications》1981,37(6):442-446
The theory of atomic scattering by a resonant standing light wave is developed. It is shown that, if the natural width of atomic transition is larger than the recoil energy and the interaction time exeeds the spontaneous decay time, the atomic motion is described by the kinetic equation for atomic distribution function. The latter is a Fokker-Planck type equation and includes the light pressure force and momentum diffusion tensor. It is found that in a strong wave the maximum value of the force is limited, whereas the diffusion tensor increases proportional to wave intensity. It is concluded that for high intensities of a standing wave, it is the atomic momentum diffusion that is responsible for scattering. 相似文献
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We propose a scheme to localize a two-level atom inside a classical standing wave field conditioned upon the measurement of the frequency of a weak probe field at resonance excitation of a two-level atomic system. Inside the classical standing wave field, the interaction between the atom and the field is position-dependent due to the Rabi frequency of the driving field; hence, as the absorption frequency of the probe field is measured, the position of an atom inside the classical standing wave field will be determined. The effects of atomic parameters on atom localization are then discussed. 相似文献
8.
Sergey V. Prants Vsevolod O. Vitkovsky Leonid E. Kon’kov 《Journal of Russian Laser Research》2011,32(6):556-563
We report on a theoretical and numerical study of the propagation of atomic beams crossing a detuned standing-wave laser beam
in the geometric-optics limit. The interplay between the external and internal atomic degrees of freedom is used to manipulate
the atomic motion along the light optical axis. By adjusting the atom–laser detuning, we demonstrate how to focus, split,
and scatter atomic beams in real experiments. The novel effect of chaotic scattering of atoms on a regular near-resonant standing
wave is found numerically and explained qualitatively. Some applications of the effects found are discussed. 相似文献
9.
基于半经典理论,分析了中性钠原子在激光驻波场中的受力特征,以此为基础分别对不同纵向运动速度和横向运动速度条件下中性钠原子的运动轨迹进行了仿真运算,得到了不同速度条件下中性钠原子的运动轨迹特征,基于累计算法进一步对不同速度条件下中性钠原子的沉积特性进行了仿真,当钠原子的纵向运动速度符合最可及速度(740 m/s)时,纳米沉积条纹的半高宽为2.78 nm,条纹对比度为38.5 ∶1,当纵向运动速度偏离最可及速度(350 m/s)时,纳米沉积条纹的半高宽为29.1 nm,其对比度下降为15 ∶1.而当中性钠原子
关键词:
原子光刻
激光驻波场
条纹半高宽
条纹对比度 相似文献
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T. Meijer J. P. Beardmore C. G. C. H. M. Fabrie J. P. van Lieshout R. P. M. J. W. Notermans R. T. Sang E. J. D. Vredenbregt K. A. H. van Leeuwen 《Applied physics. B, Lasers and optics》2011,105(4):703-713
Atom lithography uses standing wave light fields as arrays of lenses to focus neutral atom beams into line patterns on a substrate.
Laser cooled atom beams are commonly used, but an atom beam source with a small opening placed at a large distance from a
substrate creates atom beams which are locally geometrically collimated on the substrate. These beams have local offset angles
with respect to the substrate. We show that this affects the height, width, shape, and position of the created structures.
We find that simulated effects are partially obscured in experiments by substrate-dependent diffusion of atoms, while scattering
and interference just above the substrate limit the quality of the standing wave lens. We find that in atom lithography without
laser cooling the atom beam source geometry is imaged onto the substrate by the standing wave lens. We therefore propose using
structured atom beam sources to image more complex patterns on subwavelength scales in a massively parallel way. 相似文献
11.
The diffraction of the wave packet of a three-level atom in a multifrequency optical radiation field is studied. A new type
of coherent beam splitter for atoms that employs the scattering of a wave packet in the field of four standing light waves
with different spatial shifts is proposed on this basis. It is shown that this interaction scheme makes it possible to obtain
large splittings (>100ℏk) of the wave packet of a three-level Λ atom in momentum space into only two coherent components. In addition, the atoms in
these coherent components are in long-lived atomic states, which substantially simplifies the experimental implementation
of such a splitter.
Pis’ma Zh. éksp. Teor. Fiz. 66, No. 6, 386–391 (25 September 1997) 相似文献
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《Comptes Rendus de l''Academie des Sciences Series IV Physics》2001,2(4):587-593
In this contribution, we present some recent theoretical results concerning the fringe contrast in Mach–Zehnder atom interferometers and the use of Bloch states to describe atomic diffraction. We also describe the observation of diffraction of lithium at thermal energy by a quasi-resonant laser standing wave. 相似文献
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The scattering of an atom in the field of counterpropagating light waves is studied under conditions such that the state of
the atom is a superposition of the ground and excited states. For the case in which this superposition is created by the field
of a traveling wave, the momentum distribution function of the atom after scattering by a standing wave is found analytically
in the approximation of a short interaction time, when the atom’s motion can be neglected. Longer interactions of the atom
with the field are studied numerically. We also consider the case of counterpropagating light waves consisting of Gaussian
or supergaussian pulses.
Zh. éksp. Teor. Fiz. 113, 563–572 (February 1998) 相似文献
14.
M. V. Fedorov M. A. Efremov V. P. Yakovlev W. P. Schleich 《Journal of Experimental and Theoretical Physics》2003,97(3):522-538
The scattering of atoms by a resonance standing light wave is considered under conditions when the lower of two resonance levels is metastable, while the upper level rapidly decays due to mainly spontaneous radiative transitions to the nonresonance levels of an atom. The diffraction scattering regime is studied, when the Rabi frequency is sufficiently high and many diffraction maxima are formed due to scattering. The dynamics of spontaneous radiation of an atom is investigated. It is shown that scattering slows down substantially the radiative decay of the atom. The regions and characteristics of the power and exponential decay are determined. The adiabatic and nonadiabatic scattering regimes are studied. It is shown that the wave packets of atoms in the metastable and resonance excited states narrow down during scattering. A limiting (minimal) size of the wave packets is found, which is achieved upon nonadiabatic scattering in the case of a sufficiently long interaction time. 相似文献
15.
The light pressure forces acting on a two-level atom in a strong standing laser wave are calculated. It is shown that at strong saturation of a resonant atomic transition the velocity dependence of these forces include sharp variations due to multiphoton resonances. At small atomic velocities these multiphoton resonances may even change the sign of the forces. The results obtained are important for many applications of resonant light pressure, e.g. in cooling and trapping of atoms in standing laser waves. 相似文献
16.
L. V. Il’ichev 《Journal of Experimental and Theoretical Physics》2008,106(2):235-246
It is shown that spectral filtration of a significant fraction of radiation of a resonantly fluorescing atom changes its kinetics. The effect of a spectral observation event on the behavior of an atom is demonstrated by two examples: localization of an atom at its flight through a region occupied by a standing light wave and translatory dynamics of an atom at its motion along a standing light wave. In the first case, localization probabilities are calculated in the absence of spontaneous emission events and for one photoemission event. The arising distribution over the atomic momentum, which is sensitive to spectral filtration, is also calculated for one photoemission event. In the second example, it is shown that spectral filtration of spontaneous emission leads to the occurrence of an anomalous additive to the force acting on an atom in the standing-wave field. 相似文献
17.
G.A. Delone V.A. Grinchuk S.D. Kuzmichev M.L. Nagaeva A.P. Kazantsev G.I. Surdutovich 《Optics Communications》1980,33(2):149-152
The effectiveness of atom scattering by the field of a standing light wave with arbitrary interaction times is calculated in a quasiclassical approximation. The influence of spontaneous emission and the non-monochromatic nature of the field on the effective potential of an atom is discussed. The conclusions of theory are compared with the results of a recent experiment. 相似文献
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A. I. Trubilko 《JETP Letters》2013,98(5):249-254
To identify quantum cross correlations between a two-level atom and a cavity mode, the scattering of the atom on a standing light wave has been considered. It has been shown that, under coherent scattering conditions, a strong effect distinguishing the correlated state of the system from an independent state is observed. 相似文献
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A. I. Trubilko 《Journal of Experimental and Theoretical Physics》2016,123(4):557-571
Coherent scattering of a two-level atom in the field of a quantized standing wave of a micromaser is considered under conditions of initial quantum correlation between the atom and the field. Such a correlation can be produced by a broadband parametric source. The interaction leading to scattering of the atom from the nonuniform field occurs in the dispersion limit or in the wing of the absorption line of the atom. Apart from the quantized field, the atom simultaneously interacts with two classical counterpropagating waves with different frequencies, which are acting in the plane perpendicular to the atom’s propagation velocity and to the wavevector of the standing wave. Joint action of the quantized field and two classical waves induces effective two-photon and Raman resonance interaction on the working transition. The effective Hamiltonian of the interaction is derived using the unitary transformation method developed for a moving atom. A strong effect is detected, which makes it possible to distinguish the correlated initial state of the atom and the field in the scattering of atom from the state of independent systems. For all three waves, scattering is not observed when systems with quantum correlation are prepared using a high-intensity parametric source. Conversely, when the atom interacts only with the nonuniform field of the standing wave, scattering is not observed in the case of the initial factorized state. 相似文献