共查询到20条相似文献,搜索用时 15 毫秒
1.
A. Mosk S. Kraft M. Mudrich K. Singer W. Wohlleben R. Grimm M. Weidemüller 《Applied physics. B, Lasers and optics》2001,73(8):791-799
We present the first simultaneous trapping of two different ultracold atomic species in a conservative trap. Lithium and cesium
atoms are stored in an optical dipole trap formed by the focus of a CO2 laser. Techniques for loading both species of atoms are discussed and observations of elastic and inelastic collisions between
the two species are presented. A model for sympathetic cooling of two species with strongly different mass in the presence
of slow evaporation is developed. From the observed Cs-induced evaporation of Li atoms we estimate a cross-section for cold
elastic Li-Cs collisions.
Received: 1 August 2001 / Published online: 23 November 2001 相似文献
2.
Y. Torii N. Shiokawa T. Hirano T. Kuga Y. Shimizu H. Sasada 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,1(3):239-242
We utilized a blue-detuned Laguerre-Gaussian (doughnut) laser beam to trap cold rubidium atoms by optical dipole force. ”Pulsed”
polarization gradient cooling was applied to the trapped atoms to suppress the trap loss due to heating caused by random photon
scattering of the trapping light. In this trap about 108 atoms were initially captured and the trap lifetime was 1.5 s, which was consistent with losses due to background gas collisions.
This trap can readily be applied to atom guiding, compression, and evaporative cooling.
Received: 10 July 1997 / Received in final form: 5 January 1998 / Accepted: 16 January 1998 相似文献
3.
We have theoretically and experimentally investigated the focusing properties of a detuned pulsed standing wave onto a beam
of neutral atoms. In close analogy to the continuous-wave situation the dipole force leads to a periodic focusing of atoms
with a period of λ/2, provided an adiabatic condition is fulfilled. Pulsed laser light is conveniently converted to short
wavelengths and hence offers advantages in the application of atom lithography with elements of technological interest having
blue or UV resonance lines.
Received: 6 October 1999 / Revised version: 3 February 2000 / Published online: 5 April 2000 相似文献
4.
We propose a novel scheme to form a 2D dark optical surface lattice (DOSL) for cold atoms on the surface of the dense flint glass by using two sets of blue-detuned evanescent wave interference fields and a blue-detuned evanescent wave field. In the 2D DOSL, cold atoms will be trapped in the vicinity of minimum intensity and suffered the minimal light shift as well as the lowest coherence loss. The total potential and trap-depth of the individual optical micro-trap in the 2D DOSL are high enough to trap cold atoms (T = 120 μK) released from the standard magneto-optical trap (MOT), and atoms trapped in the 2D DOSL can be cooled to several μK with the efficient intensity-gradient Sisyphus cooling. The lattice constant of the DOSL can be controllable by changing the incident angles of lights. 相似文献
5.
A.B. Mundt A. Kreuter C. Russo C. Becher D. Leibfried J. Eschner F. Schmidt-Kaler R. Blatt 《Applied physics. B, Lasers and optics》2003,76(2):117-124
We demonstrate coherent coupling of the quadrupole S1/2D5/2 optical transition of a single trapped 40Ca+ ion to the standing wave field of a high-finesse cavity. The dependence of the coupling on temporal dynamics and spatial
variations of the intracavity field is investigated in detail. By precisely controlling the position of the ion in the cavity
standing wave field and by selectively exciting vibrational state-changing transitions the ion’s quantized vibration in the
trap is deterministically coupled to the cavity mode. We confirm coherent interaction of ion and cavity field by exciting
Rabi oscillations with short resonant laser pulses injected into the cavity, which is frequency-stabilized to the atomic transition.
Received: 23 August 2002 / Published online: 8 January 2003
RID="*"
ID="*"Corresponding author. E-mail: christoph.becher@uibk.ac.at
RID="**"
ID="**"Present address: Time and Frequency Division, National Institute of Standards and Technology, Boulder, CO 80305, USA 相似文献
6.
High-resolution atomic channeling using velocity-controlled atoms may be able to overcome precision limitations of the conventional
atom lithography. We have experimentally clarified the dependence of line width and contrast of atomic patterns in the channeling
region on the velocity spread of the atomic source for the first time. Thermal or velocity-selected atomic beams prepared
with a one-dimensional magneto-optical trap were employed as the atomic sources. We investigated the channeling characteristics
by measuring the frequency shifts of the atomic absorption spectra in an intense standing wave light field. As a result, we
can show that narrower line width and higher contrast atomic patterns are obtained as the velocity spread becomes narrower.
An atomic pattern with an estimated line width of 57 nm was generated when the velocity spread of the atomic source was almost
50 m/s, that is, 1/6 that of the thermal beam.
Received: 16 June 2001 / Published online: 7 November 2001 相似文献
7.
M. Lontano D. Ryutov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(3):347-351
We demonstrate the in situ detection of cold 87Rb atoms near a dielectric surface using the absorption of a weak, resonant evanescent wave. We have used this technique in
time of flight experiments determining the density of atoms falling on the surface. A quantitative understanding of the measured
curve was obtained using a detailed calculation of the evanescent intensity distribution. We have also used it to detect atoms
trapped near the surface in a standing-wave optical dipole potential. This trap was loaded by inelastic bouncing on a strong,
repulsive evanescent potential. We estimate that we trap 1.5×104 atoms at a density 100 times higher than the falling atoms.
Received 14 May 2002 Published online 8 October 2002
RID="a"
ID="a"e-mail: spreeuw@science.uva.nl 相似文献
8.
Dotsenko I Alt W Khudaverdyan M Kuhr S Meschede D Miroshnychenko Y Schrader D Rauschenbeutel A 《Physical review letters》2005,95(3):033002
We optically detect the positions of single neutral cesium atoms stored in a standing wave dipole trap with a subwavelength resolution of 143 nm rms. The distance between two simultaneously trapped atoms is measured with an even higher precision of 36 nm rms. We resolve the discreteness of the interatomic distances due to the 532 nm spatial period of the standing wave potential and infer the exact number of trapping potential wells separating the atoms. Finally, combining an initial position detection with a controlled transport, we place single atoms at a predetermined position along the trap axis to within 300 nm rms. 相似文献
9.
A. di Stefano D. Wilkowski J.H. Müller E. Arimondo 《Applied physics. B, Lasers and optics》1999,69(4):263-268
We have operated a magneto-optical trap and optical molasses for the laser cooling of cesium atoms on the basis of a five-beam
laser configuration. For the magneto-optical trap two laser beams counterpropagate along the axis of a quadrupole trap and
the remaining three beams propagate in the orthogonal plane at 120° to each other. The same optical configuration was used
for the optical molasses. We have tested the efficiency in atom collection and the temperatures reached in both cooling processes.
In comparison to previous results on a six-beam configuration, a lower number of atoms is collected, while comparable densities
are realized. The atomic temperatures have been measured through a delayed shadow-image technique, where one of the running-wave
cooling beams produces an absorptive image of the atoms on a camera.
Received: 14 January 1999 / revised version: 23 June 1999 / Published online: 8 September 1999 相似文献
10.
11.
J. Reichel W. Hänsel P. Hommelhoff T.W. Hänsch 《Applied physics. B, Lasers and optics》2001,72(1):81-89
Lithographically fabricated circuit patterns can provide magnetic guides and microtraps for cold neutral atoms. By combining
several such structures on the same ceramic substrate, we have realized the first ‘atom chips’ that permit complex manipulations
of ultracold trapped atoms or de Broglie wave packets. We show how to design magnetic potentials from simple conductor patterns
and we describe an efficient trap-loading procedure in detail. Applying the design guide, we describe some new microtrap potentials,
including a trap which reaches the Lamb–Dicke regime for rubidium atoms in all three dimensions, and a rotatable Ioffe–Pritchard
trap, which we also demonstrate experimentally. Finally, we demonstrate a device allowing independent linear positioning of
two atomic clouds which are very tightly confined laterally. This device is well suited for the study of one-dimensional collisions.
Received: 27 July 2000 / Revised version: 30 August 2000 / Published online: 22 November 2000 相似文献
12.
Ch. Grain T. Nazarova C. Degenhardt F. Vogt Ch. Lisdat E. Tiemann U. Sterr F. Riehle 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(2):317-324
We have investigated the influence of narrow-line laser cooling on the loading of Ca atoms into optical dipole traps.
To describe the narrow-line cooling of alkaline-earth atoms in combination with optical dipole trapping, we have developed
a model
that takes into account the light shifts of the cooling transition in three dimensions.
The model is compared with two experimental realizations of optical dipole traps for calcium at the wavelengths 514 nm and
10.6 μm. 相似文献
13.
M. Drewsen Ph. Laurent A. Nadir G. Santarelli A. Clairon Y. Castin D. Grison C. Salomon 《Applied physics. B, Lasers and optics》1994,59(3):283-298
We present an investigation of sub-Doppler effects in a cesium magneto-optical trap. First, a simple one-dimensional theoretical model of the trap is developed for aJ
g = 1 J
e = 2 transition. This model predicts the size of the trapped atom cloud and temperature as a function of laser intensity and detuning. In the limit of small magnetic field gradients, the trap temperature is found to be equal to the molasses temperature and a minimum size for the trap is calculated. We then describe several experiments performed in a three-dimensional cesium trap to measure the trap parameters, spring constant, friction coefficient, temperature and density. Whilst the temperature of the trapped atoms is found to be equal to the molasses temperature, in agreement with theory, the trap spring constant is found to be two orders of magnitude smaller than the one-dimensional prediction, a value close to that predicted by Doppler models. The maximum density is found to be on the order of 1012 atoms/cm3 or one atom per optical wavelength on average. When the number of trapped atoms becomes large, the temperature begins to increase dramatically. This excess temperature depends in a very simple way on the atom number, laser intensity and detuning, suggesting that its origin lies in multiple photon scattering within the trap. 相似文献
14.
V. Wippel C. Binder W. Huber L. Windholz M. Allegrini F. Fuso E. Arimondo 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,17(3):285-291
A two element magneto-optical trap (MOT) for Na and 7Li or 6Li is used to cool and trap each of them separately. A fraction of the cold atoms is maintained in the first 2P3/2 excited state by the cooling laser. These excited state atoms are ionized by laser light in the near-UV region, giving rise
to a smaller number of trapped atoms and to different loading parameters. Photoionization cross-sections were derived out
of these data. They are in reasonable agreement with data previously obtained using thermal samples and with theoretical predictions.
Received 21 March 2001 and Received in final form 3 August 2001 相似文献
15.
We demonstrate a method to count small numbers of atoms held in a deep, microscopic optical dipole trap by collecting fluorescence from atoms exposed to a standing wave of light that is blue detuned from resonance. While scattering photons, the atoms are cooled by a Sisyphus mechanism that results from the spatial variation in light intensity. The use of a small blue detuning limits the losses due to light-assisted collisions, thereby making the method suitable for counting several atoms in a microscopic volume. 相似文献
16.
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
17.
We transfer cold ^87 Rb atoms from a vapour cell chamber to a spatially separated UHV magneto-optical trap (MOT) with the assistance of a red-detuned optical guiding beam and a normal push beam. Efficient optical guiding of the cold atoms is observed within a small detuning window. A pulsed optical guiding beam enhances the transfer efficiency and hence allows us to collect more atoms in UHV MOT in a shorter time, which is favourable for our experiment of achieving Bose-Einstein condensates (BEC). Besides the easy operation, another advantage of this optical guiding technique is also demonstrated such that slower atomic beams may be efficiently transferred along horizontal direction. This study is a direct application of the optical guiding technique as a powerful tool. 相似文献
18.
F. Schmidt-Kaler J. Eschner G. Morigi C.F. Roos D. Leibfried A. Mundt R. Blatt 《Applied physics. B, Lasers and optics》2001,73(8):807-814
A novel method of ground-state laser cooling of trapped atoms utilizes the absorption profile of a three- (or multi-) level
system that is tailored by a quantum interference. With cooling rates comparable to conventional sideband cooling, lower final
temperatures may be achieved. The method was experimentally implemented to cool a single Ca+ ion to its vibrational ground state. Since a broad band of vibrational frequencies can be cooled simultaneously, the technique
will be particularly useful for the cooling of larger ion strings, thereby being of great practical importance for initializing
a quantum register based on trapped ions. We also discuss its application to different level schemes and for ground-state
cooling of neutral atoms trapped by a far-detuned standing wave laser field.
Received: 10 July 2001 / Published online: 23 November 2001 相似文献
19.
Miroshnychenko Y Alt W Dotsenko I Förster L Khudaverdyan M Meschede D Reick S Rauschenbeutel A 《Physical review letters》2006,97(24):243003
We recently demonstrated that strings of trapped atoms inside a standing wave optical dipole trap can be rearranged using optical tweezers [Y. Miroshnychenko, Nature 442, 151 (2006)]. This technique allows us to actively set the interatomic separations on the scale of the individual trapping potential wells. Here, we use such a distance-control operation to insert two atoms into the same potential well. The detected success rate of this manipulation is 16(-3)(+4)%, in agreement with the predictions of a theoretical model based on our experimental parameters. 相似文献
20.
M. Greiner I. Bloch O. Mandel T.W. Hänsch T. Esslinger 《Applied physics. B, Lasers and optics》2001,73(8):769-772
Bose–Einstein condensates of rubidium atoms are transferred into one- and two-dimensional optical lattice potentials. The
phase coherence of the condensate wavefunction in the lattice potential is studied by suddenly releasing the atoms from the
trapping potential and observing the multiple matter-wave interference pattern of several thousand expanding quantum gases.
We show how arbitrary phase gradients can be mapped onto the periodic wavefunction through the application of a potential
gradient. Furthermore, the experimentally measured strength of the momentum components is compared to a theoretical model
of the condensate wavefunction in the lattice.
Received: 3 July 2001 / Revised version: 26 September 2001 / Published online: 23 November 2001 相似文献