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1.
K. Nakagawa Y. Suzuki M. Horikoshi J.B. Kim 《Applied physics. B, Lasers and optics》2005,81(6):791-794
We have developed a simple magnetic transport method for the efficient loading of cold atoms into a magnetic trap. Laser-cooled
87Rb atoms in a magneto-optical trap (MOT) are transferred to a quadrupole magnetic trap and they are then transported as far
as 50 cm by moving magnetic trap coils with a low excess heating of atoms. A light induced atom desorption technique helps
to reduce the collision loss during the magnetic transport. Using this method, we can load cold 87Rb atoms into a magnetic trap in an ultra high vacuum chamber with high efficiency, and we can produce 87Rb condensate atoms.
PACS 39.25.+k; 32.80.Pj; 03.75.Pp 相似文献
2.
R. W. Mu Z. L. Wang Y. L. Li X. M. Ji J. P. Yin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,59(2):291-300
We experimentally demonstrate a practical scheme to form a controllable
double-well optical dipole trap for cold atoms (or cold molecules), and give
some experimental results as well as the fabrication method of a binary
π-phase plate. The dependence of the double-well characteristics on the phase
etching error of the π-phase plate and the evolution of the double-well
optical trap from two wells to a single one are studied both theoretically
and experimentally, and the experimental results are consistent with the
theoretical prediction. Furthermore, the dynamic process of loading and
splitting of cold 87Rb atoms from a standard magneto-optical trap (MOT)
into our controllable double-well one are studied by Monte Carlo
simulations. Our study shows that the loading efficiency of cold atoms from
the standard MOT into our single-well trap can reach 100%, and the
relative atomic density will be reduced from 1.0 to ∼0.5 during the
evolution of our double-well trap, in which the temperature of cold atoms is
reduced from 20 μK to ∼15 μK. In final, some potential
applications of our controllable double-well optical trap in atom and
molecule optics are briefly discussed. 相似文献
3.
Min-kang Zhou Zhong-kun Hu Xiao-chun Duan Bu-liang Sun Jin-bo Zhao Jun Luo 《Frontiers of Physics in China》2009,4(2):170-173
Precisely determining gravity acceleration g plays an important role on both geophysics and metrology. For gravity measurements and high-precision gravitation experiments,
a cold atom gravimeter with the aimed resolution of 10.−9g/Hz1/2 (1 g=9.8 m/s2) is being built in our cave laboratory. There will be four steps for our 87Rb atom gravimeter, Magneto-Optical Trap (MOT) for cooling and trapping atoms, initial state preparation, π/2-π-π/2 Raman
laser pulse interactions with cold atoms, and the final state detection for phase measurement. About 108 atoms have been trapped
by our MOT and further cooled by moving molasses, and an atomic fountain has also been observed.
相似文献
4.
5.
G. Kleine?Büning J. Will W. Ertmer C. Klempt J. Arlt 《Applied physics. B, Lasers and optics》2010,100(1):117-123
We report on a slow guided atom laser beam outcoupled from a Bose–Einstein condensate of 87Rb atoms in a hybrid trap. The acceleration of the atom laser beam can be controlled by compensating the gravitational acceleration
and we reach residual accelerations as low as 0.0027 g. The outcoupling mechanism allows for the production of a constant
flux of 4.5×106 atoms per second and due to transverse guiding we obtain an upper limit for the mean beam width of 4.6 μm. The transverse
velocity spread is only 0.2 mm/s and thus an upper limit for the beam quality parameter is M
2=2.5. We demonstrate the potential of the long interrogation times available with this atom laser beam by measuring the trap
frequency in a single measurement. The small beam width together with the long evolution and interrogation time makes this
atom laser beam a promising tool for continuous interferometric measurements. 相似文献
6.
提出了采用四台阶相位光栅与微透镜阵列组合产生一种新颖的表面空心微光阱阵列的方案,研究了表面空心微光阱阵列的光强分布,计算了相应的光学囚禁势,并讨论了该微光阱阵列在原子分子光学中的潜在应用.研究表明当用1W的YAG激光照射时,在1cm2面积上可产生近104个空心光阱,每个光阱具有较小的囚禁体积和较大的有效光强及其强度梯度,对85Rb原子的光学囚禁势可达190μK.如此深的光阱足以囚禁冷原子或冷分子,并可用于实现全光型原子或分子玻色-爱因斯坦凝聚,甚至制备新颖的光学晶格等.
关键词:
空心光阱
冷原子或冷分子
光学晶格 相似文献
7.
A three-dimensional trap for Rydberg atoms in selected Stark states has been realized experimentally. H atoms seeded in a supersonic expansion of Ar are excited to the low-field seeking n=30, k=25, |m|=0, 2 Rydberg-Stark states, decelerated from a mean initial velocity of 665 m/s to zero velocity in the laboratory frame and loaded into a three-dimensional electrostatic trap. The motion of the cold Rydberg atom cloud in the trap and the decay of the trapped atoms have been studied by pulsed electric field ionization and imaging techniques. 相似文献
8.
9.
We report on the efficient generation of cold rubidium atoms as a potential coherent atom source for atom lithography. We
successfully trapped and cooled 2.6 × 108 atoms in 5 s with a conventional magneto-optical trap simply by enlarging the diameter of the laser beam to 20 mm. The size
of the laser-cooled atom cloud was measured to be 10 × 7 × 7 mm3. The number of trapped atoms was approximately 10 times as large as that of previous typical results, while the loading time
of atoms remained the same. 相似文献
10.
We demonstrate an experimental setup for the production of a beam source of cold 87Rb atoms. The atoms are extracted from a trapped cold atomic cloud in an unbalanced three-dimensional magneto-optical trap. Via a radiation pressure difference generated by a specially designed leak tunnel along one trapping laser beam, the atoms are pushed out continuously with low velocities and a high flux. The most-probable velocity in the beam is varied from 9 m/s to 19 m/s by varying the detuning of the trapping laser beams in the magneto-optical trap and the flux can be tuned up to 4×109 s-1 by increasing the intensity of the trapping beams. We also present a simple model for describing the dependence of the beam performance on the magneto-optical trap trapping laser intensity and the detuning. 相似文献
11.
Electron-loss cross sections of O q+(q = 1 4) colliding with He,Ne and Ar atoms are measured in the intermediate velocity regime.The ratios of the cross sections of two-electron loss to that of one-electron loss R 21 are presented.It is shown that single-channel analysis is not sufficient to explain the results,but that projectile electron loss,electron capture by the projectile and target ionization must be considered together to interpret the experimental data.The screening and antiscreening effects can account for the threshold velocity results,but cannot explain the dependence of the ratio R 21 on velocity quantitatively.In general,the effective charge of the target atom increases with velocity increasing because the high-speed projectile ion can penetrate into the inner electronic shell of target atom.Ne and Ar atoms have similar effective charges in this velocity regime,but He atoms have smaller ones at the same velocities due to its smaller nuclear charge. 相似文献
12.
We propose that the driven cold atomic system whose trap potential is periodically perturbed via parametric modulation of the magnetic field-gradien is a novel system to investigate the complex dynamics in nonlinear dynamical systems. We calculate the atomic trajectories and basins of attraction by varying the modulation amplitude and the modulation frequency. The calculation results show parametric resonance similar to those in Kim et. al.'s work [Opt. Commun. 236 (2004) 349] on cold atoms under parametric modulation of trap laser intensities in the case of small modulation amplitude or low modulation frequency. As the modulation amplitude or the modulation frequency is increased, the nonlinear effects are enhanced so that the dynamics of the system shows a wide variety of nonlinear behaviors, such as period doubling and chaos. We experimentally demonstrate the parametric resonance when the magnetic field gradient is parametrically modulated, which evidences the realization of the proposed system. We expect that this system is useful for understanding the stochastic phenomena occurring between complex basins of attraction, such as fluctuation induced transitions across the complex basin boundaries. 相似文献
13.
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
14.
Extending a release-and-recapture scheme to single atom optical tweezer for effective temperature evaluation 下载免费PDF全文
By recording the fluorescence fraction of the cold atoms remaining in the magneto-optical trap (MOT) as a function of the release time,the release-and-recapture (R&R) method is utilized to evaluate the effective temperature of the cold atomic ensemble.We prepare a single atom in a large-magnetic-gradient MOT and then transfer the trapped single atom into a 1064-nm microscopic optical tweezer.The energy of the single atom trapped in the tweezer is further reduced by polarization gradient cooling (PGC) and the effective temperature is evaluated by extending the R&R technique to a single atom tweezer.The typical effective temperature of a single atom in the tweezer is improved from about 105 μK to about 17 μK by applying the optimum PGC phase. 相似文献
15.
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
16.
Xin-ye XU Wen-li WANG Qing-hong ZHOU Guo-hui LI Hai-ling JIANG Lin-fang CHEN Jie YE Zhi-hong ZHOU Yin CAI Hai-yao TANG Min ZHOU 《Frontiers of Physics in China》2009,4(2):160-164
The experiments on the laser cooling and trapping of ytterbium atoms are reported, including the two-dimensional transversal
cooling, longitudinal velocity Zeeman deceleration, and a magneto-optical trap with a broadband transition at a wavelength
of 399 nm. The magnetic field distributions along the axis of a Zeeman slower were measured and in a good agreement with the
calculated results. Cold ytterbium atoms were produced with a number of about 107 and a temperature of a few milli-Kelvin. In addition, using a 556-nm laser, the excitations of cold ytterbium atoms at 1S0-3P1 transition were observed. The ytterbium atoms will be further cooled in a 556-nm magneto-optical trap and loaded into a three-dimensional
optical lattice to make an ytterbium optical clock.
相似文献
17.
18.
Rydberg hydrogen atom in the presence of uniform magnetic and quadrupolar electric fields 总被引:1,自引:0,他引:1
Laser cooling and trapping offers the possibility of confining a sample of radioactive atoms in free space. Here, we address the question of how best to take advantage of cold atom properties to perform the observation of as highly forbidden a line as the 6S-7S Cs transition for achieving, in the longer term, atomic parity violation (APV) measurements in radioactive alkali isotopes. Another point at issue is whether one might do better with stable, cold atoms than with thermal atoms. To compensate for the large drawback of the small number of atoms available in a trap, one must take advantage of their low velocity. To lengthen the time of interaction with the excitation laser, we suggest choosing a geometry where the laser beam exciting the transition is colinear to a slow, cold atomic beam, either extracted from a trap or prepared by Zeeman slowing. We also suggest a new observable physical quantity manifesting APV, which presents several advantages: specificity, efficiency of detection, possibility of direct calibration by a parity conserving quantity of a similar nature. It is well adapted to a configuration where the cold atomic beam passes through two regions of transverse, crossed electric fields, leading both to differential measurements and to strong reduction of the contributions from the M1-Stark interference signals, potential sources of systematics in APV measurements. Our evaluation of signal-to-noise ratios shows that with available techniques, measurements of transition amplitudes, important as required tests of atomic theory, should be possible in 133Cs with a statistical precision of 10-3 and probably also in Fr isotopes for production rates of
Fr atoms s-1. For APV measurements to become realistic, some practical realization of the collimation of the atomic beam as well as multiple passages of the excitation beam matching the atomic beam looks essential.Received: 5 March 2003, Published online: 17 July 2003PACS:
32.80.Ys Weak-interaction effects in atoms - 32.70.Cs Oscillator strengths, lifetimes, transition moments - 32.80.Pj Optical cooling of atoms; trapping - 39.90.+d Other instrumentation and techniques for atomic and molecular physicsS. Sanguinetti: Also at E. Fermi Physics Dept., Pisa Univ., Pisa, Italy. 相似文献
19.
20.
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