共查询到20条相似文献,搜索用时 15 毫秒
1.
Single-beam optical bottle for cold atoms using a conical lens 总被引:2,自引:0,他引:2
L. Cacciapuoti M. de Angelis G. Pierattini G.M. Tino 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,14(3):373-376
We report a new method to generate an optical dipole potential with a null intensity region surrounded in all directions by
light walls. This is achieved with a simple scheme based on a conical lens. Applications to optical trapping of neutral atoms
are discussed.
Received 4 September 2000 and Received in final form 21 January 2001 相似文献
2.
F. Levi A. Godone J. Vanier S. Micalizio G. Modugno 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,12(1):53-59
The paper is concerned with the line shapes of resonance phenomena observed in Coherent Population Trapping (CPT) applied
to alkali atoms in a cell containing a buffer gas. Significant asymmetries and departures from a Lorentzian shape have been
observed in connection with the measurement of dark lines and CPT maser emission profiles. Measurements are reported as a
function of the power and frequency tuning of the laser used to create the CPT phenomenon. The paper reports on different
experimental conditions and a comparison between theory and experiments is made for the cases of cesium and rubidium in a
buffer gas.
Received 3 March 2000 and Received in final form 10 April 2000 相似文献
3.
在获得光致原子解吸附(light-induced atom desorption,LIAD)效应的基础上,从理论和实验方面分析了LIAD对铯原子磁光阱装载的动力学过程的影响,特别是背景原子对磁光阱的影响.通过实验获得了不同光强和照射时间下关闭解吸附光后磁光阱中铯原子的衰减过程,理论模型定量地描述了背景铯原子造成压强的变化及其对最终平衡态下真空度的影响.该研究对中性原子的长时间俘获,有效控制磁光阱中原子的装载过程具有重要意义.
关键词:
光致原子解吸附
磁光阱
激光冷却与俘获 相似文献
4.
L. Fleischmann J. Bonn B. Bornschein P. Leiderer E.W. Otten M. Przyrembel Ch. Weinheimer 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,16(3):521-529
The dewetting dynamics of solid films of hydrogen isotopes, quench-condensed on a graphite substrate, was measured at various
temperatures below desorption by observing the stray light from the film. A schematic model describing the dewetting process
by surface diffusion is presented, which agrees qualitatively with our data. The activation energies of different hydrogen
isotopes for surface diffusion were determined. The time constant for dewetting of a quench-condensed film at the working temperature of 1.86 K of the mainz neutrino mass experiment was extrapolated.
Received 30 December 1999 相似文献
5.
M. Gangl H. Ritsch 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,8(1):29-40
We develop quantum models for the combined external and internal motion of atoms in a strongly coupled driven cavity mode
including the transverse degrees of freedom. Using a simplified Gaussian mode function we determine the parameter regimes
and prospects of 3D cooling and confinement of one or two atoms in the cavity field. Analysing the field dynamics for slow
atoms traversing the cavity, we show that the spectrum of the transmitted and spontaneously scattered light contains ample
information on the motional dynamics of the atom and can be nicely used to investigate the cooling properties of the system.
Including several atoms in the dynamics we show how motional correlations build up by the common interaction with the cavity
field. This can be looked upon as collisions at far distance and can be monitored via the transmitted field dynamics.
Received 5 March 1999 and Received in final form 4 May 1999 相似文献
6.
N.F. Allard J. Kielkopf I. Drira P. Schmelcher 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,12(2):263-268
We present a theoretical profile of the Lyman line of atomic hydrogen perturbed by collisions with neutral hydrogen atoms and protons. We use a general unified theory
in which the electric dipole moment varies during a collision. A collision-induced satellite appears on Lyman , correlated to the asymptotically forbidden transition of H2. As a consequence, the appearance of the line wing between Lyman and Lyman is shown to be sensitive to the relative abundance of hydrogen ions and neutral atoms, and thereby to provide a temperature
diagnostic for stellar atmospheres and laboratory plasmas.
Received 15 January 2000 and Received in final form 17 May 2000 相似文献
7.
U.V. Poulsen K. Mølmer 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,11(2):151-157
We present theoretical calculations for the reflection of atoms from a magnetic surface with a sinusoidal magnetization. A
fully quantum mechanical treatment is possible because the problem may be reduced to an effective one-dimensional one. Results
of numerical wave-packet calculations are presented and compared with an analytical model in which the atoms separate into
different internal state components which follow classical paths in different potentials.
Received 21 October 1999 and Received in final form 18 January 2000 相似文献
8.
M.-C. Chung M. Kaulke I. Peschel M. Pleimling W. Selke 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,18(4):655-661
The influence of surface defects on the critical properties of magnetic films is studied for Ising models with nearest-neighbour
ferromagnetic couplings. The defects include one or two adjacent lines of additional atoms and a step on the surface. For
the calculations, both density-matrix renormalization group and Monte Carlo techniques are used. By changing the local couplings
at the defects and the film thickness, non-universal features as well as interesting crossover phenomena in the magnetic exponents
are observed.
Received 27 July 2000 and Received in final form 5 October 2000 相似文献
9.
Reflection of thermal atoms by a pulsed standing wave 总被引:1,自引:0,他引:1
P. Ryytty M. Kaivola 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,12(3):415-423
Reflection of thermal atoms by a pulsed standing wave with a duration in the nanosecond range is studied. The momentum distribution
of the reflected atoms is determined by calculations based on the adiabatic atom-photon interactions. It is shown that with
a proper choice of the field intensity and the pulse duration the standing-wave pattern functions as a row of independent
atom mirrors. At an optimum choice of the parameter values, the fraction of the elastically reflected atoms is more than 20%.
Furthermore, we show that the pulsed standing-wave mirror can be used to manipulate their final momentum distribution. When
using laser pulses with an intensity of several tens of MW/cm2, tens of thousands of atoms can be reflected by a single laser pulse.
Received 3 December 1999 and Received in final form 25 April 2000 相似文献
10.
P. Domokos T. Kiss J. Janszky 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,14(1):49-53
A beam of diatomic molecules scattered off a standing wave laser mode splits according to the rovibrational quantum state
of the molecules. Our numerical calculation shows that single state resolution can be achieved by properly tuned, monochromatic
light. The proposed scheme allows for selecting non-vibrating and non-rotating molecules from a thermal beam, implementing
a laser Maxwell's demon to prepare a rovibrationally cold molecular ensemble.
Received 23 August 2000 and Received in final form 17 November 2000 相似文献
11.
G. Labeyrie A. Browaeys W. Rooijakkers D. Voelker J. Grosperrin B. Wanner C.I. Westbrook A. Aspect 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,7(3):341-350
We have constructed a magneto-optical funnel for He atoms and studied its properties using a laser cooled, highly mono-energetic
atomic beam. A simple model of its action allows us to quantitatively understand the observed spot size and “focal length”.
We show that for a fast beam, the velocity damping coefficient plays an important role in determining the focal length of
the device. The observed spot size is limited mainly by transverse heating processes which impose a transverse velocity spread.
The device also permits easy scanning of the focussed spot.
Received 30 October 1998 and Received in final form 27 January 1999 相似文献
12.
S. Schinzer S. Köhler G. Reents 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,15(1):161-168
We examine the step dynamics in a 1+1-dimensional model of epitaxial growth based on the BCF-theory. The model takes analytically
into account the diffusion of adatoms, an incorporation mechanism and an Ehrlich-Schwoebel barrier at step edges. We find
that the formation of mounds with a stable slope is closely related to the presence of an incorporation mechanism. We confirm
this finding using a solid-on-solid model in 2+1 dimensions. In the case of an infinite step edge barrier we are able to calculate
the saturation profile analytically. Without incorporation but with inclusion of desorption and detachment we find a critical
flux for instable growth but no slope selection. In particular, we show that the temperature dependence of the selected slope
is solely determined by the Ehrlich-Schwoebel barrier which opens a new possibility in order to measure this fundamental barrier
in experiments.
Received 11 May 1999 and Received in final form 6 November 1999 相似文献
13.
J.H. Xu F. Mango G. Alzetta R.A. Bernheim 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,10(2):243-246
Alkali metals adsorbed to surface films of the polymer poydimethylsiloxane (PDMS) have been shown to exhibit a unique photodesorption
behavior, characterized by a frequency threshold and high efficiency. In this work, the temperature dependence of the photodesorption
yields of Na and Na
2
from PDMS surfaces were measured between room temperature and 183 K. Over most of the temperature range, the yields exhibited
an Arrhenius behavior characterized by thermal activation energies of 0.36 eV and 0.34 eV for Na and Na
2
, respectively. These values are suggestive of a surface diffusion as one of the elementary steps in the photodesorption mechanism.
Moreover, the similarity of the two values indicates that the same elementary step applies to the desorption of both Na and
Na
2
.
Received 23 April 1999 and Received in final form 15 July 1999 相似文献
14.
15.
H. Suno L. Andric T.P. Grozdanov R. McCarroll 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,17(2):213-220
A combination of the complex-coordinate method and the Lanczos recursion scheme is implemented in the discrete variable representation
(DVR) to obtain total photoionization cross-sections using an iterative procedure. Applications to photoionization of hydrogen
atoms in electric fields and sodium atoms in electric and parallel electric and magnetic fields are presented and discussed.
Received 15 May 2000 and Received in final form 4 October 2000 相似文献
16.
F. Mango E. Maccioni 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,50(3):253-256
Laser-induced fluorescence (LIF) of calcium atoms at room
temperature has been observed in a polydimethylsiloxane (PDMS) coated cell
when the walls are illuminated with non resonant visible light. Ca atomic
density in the gas phase, monitored by the LIF, is much higher than normal
room-temperature vapour pressure of calcium. In past years photon-stimulated desorption (PSD) was observed for several
alkali metals that adsorbed to solid films of PDMS polymers. High yields of
photo-desorbed atoms (and molecules in the case of sodium) can be induced,
at room temperature and below, by weak intensity radiation. The desorption
is characterised by a frequency threshold, whereas any power threshold is
undetectable. The calcium photo-ejection is characterised both by a
frequency threshold (about 18 500 cm-1) and by an observable power
threshold (whose value becomes lower when the photo-ejecting light
wavelength decreases). 相似文献
17.
A continuous cold atomic beam from a magneto-optical trap 总被引:3,自引:0,他引:3
L. Cacciapuoti A. Castrillo M. de Angelis G.M. Tino 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,15(2):245-249
We have developed and characterized a new method to produce a continuous beam of cold atoms from a standard vapour-cell magneto-optical
trap (MOT). The experimental apparatus is very simple. Using a single laser beam it is possible to hollow out in the source
MOT a direction of unbalanced radiation pressure along which cold atoms can be accelerated out of the trap. The transverse
cooling process that takes place during the extraction reduces the beam divergence. The atomic beam is used to load a magneto-optical
trap operating in an ultra-high vacuum environment. At a vapour pressure of 10-8mbar in the loading cell, we have produced a continuous flux of 7×107atoms/s at the recapture cell with a mean velocity of 14 m/s. A comparison of this method with a pulsed transfer scheme is
presented.
Received 19 February 2001 相似文献
18.
The nanosecond desorption of ground-state K atoms from potassium halides was investigated for the first time using a laser-induced fluorescence method with synchrotron radiation and laser pulses. It was found that the desorption consists of a nanosecond component and a slow one of > 180 ns response time. The fast desorption is several orders of magnitude faster than existing results for the time response of ground-state alkali desorption. Therefore, the fast desorption of ground-state alkali atoms cannot be interpreted in terms of the existing mechanisms based on thermal processes and requires a new desorption model. We suggest that the lattice instability due to electronic excitation in the surface layer may play an important role in the fast desorption of ground-state alkali atoms. 相似文献
19.
I. E. Mazetsa 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,8(3):371-375
We present a self-consistent method of taking into account back action of a laser radiation to a Bose-Einstein condensate
of neutral atoms. The light is coherently scattered inside the degenerate atomic sample, thus its intensity and, consequently,
the atomic ground level AC Stark shift are spatially varying. This leads to a small deformation of the atomic cloud and, if
the external radiation is abruptly switched off, to generation of collective excitations.
Received 8 May 1999 and Received in final form 11 October 1999 相似文献