共查询到20条相似文献,搜索用时 281 毫秒
1.
B. Rohwedder 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,13(2):255-260
Fringe shapes in a multiple-beam de Broglie-wave interferometer based on the atomic Kapitza-Dirac effect are studied. An all-optical
implementation of such a device is proposed. A realization in the time-domain, using Bose-Einstein condensates released from
a trap, seems viable within the present state of the art.
Received 5 April 2000 and Received in final form 14 July 2000 相似文献
2.
C.M. Dion A. Keller O. Atabek 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,14(2):249-255
Using a rigid-rotor model, we study the orientation dynamics of polar diatomic molecules excited by experimentally available
half-cycle pulses. The results of the numerical solution of the time-dependent Schr?dinger equation are compared to those
of an approximate “sudden-impact” impulsive model neglecting the molecular rotation during the pulse. We show that efficient
orientation is achieved during time periods of several picoseconds for LiCl. For short pulses, where the kicked molecule model
is valid, orientation turns out to be mainly sensitive to the time-integrated field amplitude and not the shape or rise time
of the pulse.
Received 16 August 2000 and Received in final form 4 December 2000 相似文献
3.
An atom faucet 总被引:3,自引:0,他引:3
W. Wohlleben F. Chevy K. Madison J. Dalibard 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,15(2):237-244
We present a simple and efficient source of slow atoms. From a background vapour loaded magneto-optical trap (MOT), a thin
laser beam extracts a continuous jet of cold rubidium atoms. The jet that is typical to leaking MOT systems is created without
any optical parts placed inside the vacuum chamber. We also present a simple three dimensional numerical simulation of the
atomic motion in the presence of these multiple saturating laser fields combined with the inhomogeneous magnetic field of
the MOT. At a pressure of P
Rb87 = 10-8 mbar and with a moderate laser power of 10 mW per beam, we generate a flux Φ = 1.3×108 atoms/s with a mean velocity of 14 m/s and a divergence of 10 mrad.
Received 13 January 2001 相似文献
4.
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
5.
E. Rasel F. Pereira Dos Santos F. Saverio Pavone F. Perales C.S. Unnikrishnan M. Leduc 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,7(3):311-316
We report a study of transverse laser cooling on a metastable helium beam using spectrally broadened diode lasers (“white
light") to increase its flux. For this purpose, beam profile and atomic flux versus laser power and other parameters have been characterized. We have performed experiments to compare this technique with other
transverse cooling methods using monochromatic light. Best results are obtained with a “ziz-zag" configuration using “white
light".
Received 21 December 1998 and Received in final form 27 May 1999 相似文献
6.
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
7.
P. Cren C.F. Roos A. Aclan J. Dalibard D. Guéry-Odelin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,20(1):107-116
We demonstrate experimentally the continuous and pulsed loading of a slow and cold atomic beam into a magnetic guide. The
slow beam is produced using a vapor loaded laser trap, which ensures two-dimensional magneto-optical trapping, as well as
cooling by a moving molasses along the third direction. It provides a continuous flux larger than 109 atoms/s with an adjustable mean velocity ranging from 0.3 to 3 m/s, and with longitudinal and transverse temperatures smaller
than 100 μK. Up to 3×108 atoms/s are injected into the magnetic guide and subsequently guided over a distance of 40 cm.
Received 19 February 2002 Published online 28 June 2002 相似文献
8.
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
9.
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
10.
C.H. Raymond Ooi K.-P. Marzlin J. Audretsch 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(2):259-267
A general scheme for reducing the center-of-mass entropy is proposed. It is based on the repetition of a cycle, composed of
three concepts: velocity selection, deceleration and irreversible accumulation. Well-known laser techniques are used to represent
these concepts: Raman π-pulse for velocity selection, STIRAP for deceleration, and a single spontaneous emission for irreversible
accumulation. No closed pumping cycle nor repeated spontaneous emissions are required, so the scheme is applicable to cool
a molecular gas. The quantum dynamics are analytically modelled using the density matrix. It is shown that during the coherent
processes the gas is translationally cooled. The internal states serve as an entropy sink, in addition to spontaneous emission.
This scheme provides new possibilities to translationally laser-cool molecules for high precision molecular spectroscopy and
interferometry.
Received 25 June 2002 / Received in final form 28 September 2002 Published online 12 November 2002
RID="a"
ID="a"e-mail: ooi@spock.physik.uni-konstanz.de
RID="b"
ID="b"e-mail: Peter.Marzlin@uni-konstanz.de
RID="c"
ID="c"e-mail: Juergen.Audretsch@uni-konstanz.de 相似文献
11.
L. Sanchez-Palencia P. Horak G. Grynberg 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(3):353-364
We numerically study the spatial diffusion of an atomic cloud experiencing Sisyphus cooling in a three-dimensional linlin optical lattice in a broad range of lattice parameters. In particular, we investigate the dependence on the size of the
lattice sites which changes with the angle between the laser beams. We show that the steady-state temperature is largely independent
of the lattice angle, but that the spatial diffusion changes significantly. It is shown that the numerical results fulfill
the Einstein relations of Brownian motion in the jumping regime as well as in the oscillating regime. We finally derive an
effective Brownian motion model from first principles which gives good agreement with the simulations.
Received 8 August 2001 and Received in final form 6 November 2001 相似文献
12.
13.
G. Morigi H. Walther 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,13(2):261-269
We study from the point of view of quantum information the properties of the collective oscillations of a linear chain of
ions trapped in a linear Paul trap and composed of two ion species. We discuss extensively sympathetic cooling of the chain
and the effect of anharmonicity on laser-cooling and quantum-information processing.
Received 19 May 2000 相似文献
14.
P. Ryytty M. Kaivola C.G. Aminoff 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,7(3):369-372
We study the deflection of sodium atoms by a resonantly tuned pulsed standing wave of high field intensity. The effects of
the phase fluctuations of the pulsed laser field on the momentum distribution of the deflected atoms are experimentally determined.
The results are explained using a theoretical model based on the generalized density matrix formalism of two-level atoms.
Received 23 November 1998 and Received in final form 27 January 1999 相似文献
15.
I. Josopait L. Dobrek L. Santos A. Sanpera M. Lewenstein 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(3):385-391
The atom optics of Bose-Einstein condensates containing a vortex of circulation one is discussed. We first analyze in detail
the reflection of such a condensate falling on an atomic mirror. In a second part, we consider a rotating condensate in the
case of attractive interactions. We show that for sufficiently large nonlinearity the rotational symmetry of the rotating
condensate is broken.
Received 16 September 2002 / Received in final form 17 November 2002 Published online 11 February 2003 相似文献
16.
J.G.C. Tempelaars R.J.W. Stas P.G.M. Sebel H.C.W. Beijerinck E.J.D. Vredenbregt 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(1):113-121
We employ laser cooling to intensify and cool an atomic beam of metastable Ne(3
s) atoms. Using several collimators, a slower and a compressor we achieve a 20Ne* flux of 6×10
10
atoms/s in an 0.7 mm diameter beam traveling at 100 m/s, and having longitudinal and transverse temperatures of 25 mK and 300μK, respectively. This constitutes the highest flux in a concentrated beam achieved to date with metastable rare gas atoms.
We characterize the action of the various cooling stages in terms of their influence on the flux, diameter and divergence
of the atomic beam. The brightness and brilliance achieved are 2.1 ×10
21
s-1m-2sr-1 and 5.0 ×10
22
s-1m-2sr-1, respectively, comparable to the highest values reported for alkali-metal beams. Bright beams of the 21Ne and 22Ne isotopes have also been created.
Received 22 June 2001 相似文献
17.
18.
F. Arias de Saavedra E. Buendıa F.J. Gálvez A. Sarsa 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,13(2):201-206
A generalized Hylleraas-type basis set with three nonlinear parameters is proposed to study three-body systems interacting
via coulomb forces within the framework of non-relativistic quantum mechanics. This basis set improves the rate of convergence
with respect to previous ones, specially for non-symmetric systems and excited states of two electron atoms. Accurate binding
energies and other properties for S-states of helium-like ions, muonic molecules and the positronium negative ion are reported.
Received 21 July 2000 and Received in final form 4 October 2000 相似文献
19.
J. Eschner 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(3):341-345
Taking recent experiments as examples, we discuss the conditions for sub-wavelength probing of optical field structures by
single trapped atoms. We calculate the achievable resolution, highlighting its connection to the fringe visibility in an interference
experiment. We show that seemingly different physical pictures, such as spatial averaging, phase modulation, and which-way
information, describe the situation equally and lead to identical results. The connection to Bohr's moving slit experiment
is pointed out.
Received 10 September 2002 Published online 17 December 2002 相似文献
20.
D. Lucas P. Horak G. Grynberg 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,7(3):261-267
We study one-dimensional Sisyphus cooling on the transition of
87
Rb atoms in the electric field created by two counter-propagating linearly polarized laser beams with an angle of between the polarization directions. The neighbouring F
'=0 and F
'=2 excited states are found to play an important role in the cooling mechanism, e.g., by inhibiting a significant population of the velocity-selective dark state. Our experimental data, such as temperatures
and probe absorption coefficients, agree well with the results of quantum Monte-Carlo wavefunction simulations.
Received 26 November 1998 and Received in final form 20 April 1999 相似文献