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1.
We report the realization of ytterbium magneto-optical trap (MOT) operating on the dipole-allowed ^1S0 - ^1P1 transition at 398.9nm. The MOT is loaded by a slowed atomic beam produced by a Zeeman slower. All seven stable isotopes of Yb atoms could be trapped separately at different laser detuning values. Over 10^7 174 Yb atoms are collected in the MOT, whereas the atom number of fermionic isotope ^171Yb is roughly 2.3 × 10^6 due to a lower abundance. Without the Zeeman slower the trapped atom numbers are one order of magnitude lower. Both the even and odd isotopes are recognized as excellent candidates of optical clock transition, so the cooling and trapping of ytterbium atoms by the blue MOT is an important step for building an optical clock. 相似文献
2.
D. Sukachev K. Chebakov A. Sokolov A. Akimov N. Kolachevsky V. Sorokin 《Optics and Spectroscopy》2011,111(4):633-638
We demonstrated laser cooling and trapping of thulium atoms at sub-Doppler temperatures in a magneto-optical trap (MOT). Up
to 3 × 106 thulium atoms were trapped in the MOT at temperatures down to 25(5) μK which is approximately 10 times lower than the Doppler
limit. The lifetime of atoms in the MOT varied between 0.3–1.5 s and was restricted mostly by optical leaks from the upper
cooling level. The lower limit for the leaking rate was estimated to be 22(6) s−1. Due to a big magnetic moment of Tm atoms, a part of them were trapped in a magnetic trap from the quadrupole field of the
MOT. We observed about 3 × 104 purely magnetically trapped atoms at temperature of 25 μK with a lifetime in the trap of 0.5 s. Also we set up a “dark” MOT
consisting of six crossed hollow beams which increased the number of trapped atoms by a factor of 5 leading to 1.5 × 107 atoms at the expense of higher temperature. 相似文献
3.
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
4.
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
5.
A. Ridinger S. Chaudhuri T. Salez U. Eismann D. R. Fernandes K. Magalhães D. Wilkowski C. Salomon F. Chevy 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,65(1-2):223-242
We present the design, implementation and characterization of a dual-species magneto-optical trap (MOT) for fermionic 6Li and 40K atoms with large atom numbers. The MOT simultaneously contains 5.2 × 109 6Li-atoms and 8.0 × 109 40K-atoms, which are continuously loaded by a Zeeman slower for 6Li and a 2D-MOT for 40K. The atom sources induce capture rates of 1.2 × 109 6Li-atoms/s and 1.4 × 109 40K-atoms/s. Trap losses due to light-induced interspecies collisions of ~65% were observed and could be minimized to ~10% by using low magnetic field gradients and low light powers in the repumping light of both atomic species. The described system represents the starting point for the production of a large-atom number quantum degenerate Fermi-Fermi mixture. 相似文献
6.
We have investigated the all-optical generation of ions by photo-ionisation of atoms generated by pulsed laser ablation. A
direct comparison between a resistively heated oven source and pulsed laser ablation is reported. Pulsed laser ablation with
10 ns Nd:YAG laser pulses is shown to produce large calcium flux, corresponding to atomic beams produced with oven temperatures
greater than 650 K. For an equivalent atomic flux, pulsed laser ablation is shown to produce a thermal load more than one
order of magnitude smaller than the oven source. The atomic beam distributions obey Maxwell–Boltzmann statistics with most
probable speeds corresponding to temperatures greater than 2200 K. Below a threshold pulse fluence between 280 mJ/cm2 and 330 mJ/cm2, the atomic beam is composed exclusively of ground-state atoms. For higher fluences ions and excited atoms are generated. 相似文献
7.
We successfully produced periodic ytterbium (Yb) narrow lines on a substrate using near-resonant laser light and the direct-write atom-lithography technique. The Yb atom is a promising material for nanofabrication using atom optics due to its electrical conductivity, the laser wavelength required for handling the atoms, the vapor pressure of the fabrication process, etc. The 174Yb atoms collimated by Doppler cooling were channeled by the dipole force of an optical standing wave and then deposited onto a substrate. We clearly observed a grating pattern of Yb atoms fabricated on the substrate with a line separation of approximately 200 nm after examining the surface of the substrate with atomic force microscope. This is the first demonstration of nanofabrication using the atom-optical approach with Yb atoms. PACS 32.80.-t; 32.80.-Pj 相似文献
8.
E. Dimova O. Morizot G. Stern C. L. Garrido Alzar A. Fioretti V. Lorent D. Comparat H. Perrin P. Pillet 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(2):299-308
We have demonstrated and modeled a simple and efficient method to transfer atoms from a first Magneto-Optical Trap (MOT) to
a second one. Two independent setups, with cesium and rubidium atoms respectively, have shown that a high power and slightly
diverging laser beam optimizes the transfer between the two traps when its frequency is red-detuned from the atomic transition.
This pushing laser extracts a continuous beam of slow and cold atoms out of the first MOT and also provides a guiding to the
second one through the dipolar force. In order to optimize the transfer efficiency, the dependence of the atomic flux on the
pushing laser parameters (power, detuning, divergence and waist) is investigated. The atomic flux is found to be proportional
to the first MOT loading rate. Experimentally, the transfer efficiency reaches 70%, corresponding to a transfer rate up to
2.7×108 atoms/s with a final velocity of 5.5 m/s. We present a simple analysis of the atomic motion inside the pushing–guiding laser,
in good agreement with the experimental data. 相似文献
9.
Evaporative cooling of ultracold Yb atoms near the quantum-degenerate regime was experimentally studied. Three bosons of 170Yb, 172Yb, 176Yb and two fermions of 171Yb and 173Yb were evaporatively cooled in a crossed far-off resonant trap (FORT). We observed that 170Yb and 172Yb were not concentrated into the crossed region. We found that, in the cases of 176Yb atoms, atoms were concentrated well into the crossed region. The following evaporative cooling in the crossed region, however, did not work well. We performed the simultaneous trapping and sympathetic cooling in the crossed FORT by use of 172Yb-174Yb, 174Yb-176Yb, 172Yb-176Yb, and 171Yb-174Yb pairs. We observed that evaporative cooling worked well. This result shows that we succeeded in the enhancement of the atom collision rate. Especially, by use of 174Yb-176Yb mixture, we obtained cold 176Yb whose phase space density was 0.02. We observed a large atom loss, which limited the further sympathetic evaporative cooling. We also evaporatively cooled 174Yb in a 1D optical lattice. Evaporative cooling worked very well because the atoms were initially trapped at a high density. After evaporative cooling, we obtained very cold atoms, and T/T F was estimated to be 1.2. 相似文献
10.
An ion trap-based Quantum system has been one of the leading architectures toward building a scalable and practical quantum computer. The trapped ion system also has been used for precision experiments such as quantum sensing, metrology, and atomic clock. For the ion-trap experiment, searching resonant frequencies of atomic isotopes are essential for selectively ionization and trapping a specific isotope. In this work, we set up an Yb fluorescence spectroscopy for detecting 399 nm photons of 1S0 → 1P1 transition of the Yb gas from a heated oven. We observed the relative frequency differences between the Yb isotopes and calibrated an optical wavemeter comparing with previous literatures. In addition, we obtain characteristic properties of the atomic oven such as gas’ velocity and density distribution at different oven temperatures. Our experiment can offer a relatively simple and cost-efficient apparatus of spectroscopy and can be useful for designing trap devices in the trapped-ion experiment. 相似文献
11.
G. Stancari S. N. Atutov R. Calabrese L. Corradi A. Dainelli C. de Mauro A. Khanbekyan E. Mariotti P. Minguzzi L. Moi S. Sanguinetti L. Tomassetti S. Veronesi 《The European physical journal. Special topics》2007,150(1):389-392
Francium is one of the best candidates for atomic parity
nonconservation (APNC) and for the search of permanent electric
dipole moments (EDMs). APNC measurements test the weak force
between electrons and nucleons at very low momentum transfers. They
also represent a unique way to detect weak nucleon-nucleon
interactions. EDMs are instead related to the time-reversal
symmetry. Preliminary to these fundamental measurements are
precision studies in atomic spectroscopy and the development of
magneto-optical traps (MOT), which partially compensate for the lack
of stable Fr isotopes. At LNL Legnaro, francium is produced by
fusion of 100-MeV 18O with 197Au in a thick target,
followed by evaporation of neutrons from the compound nucleus.
Francium diffuses inside the hot target (1200 K) and is surface
ionized for injection at 3 keV in an electrostatic beamline.
Typically, we produce 1×106 (210Fr ions)/s for a
primary flux of 1.5×1012 particles/s. We have studied
Fr yields as a function of primary beam energy, intensity, and
target temperature. Information on the efficiency of bulk
diffusion, surface desorption and ionization is deduced. The beam
then enters a Dryfilm-coated cell, where it is neutralized on a
heated yttrium plate. The escape time of neutral Fr (diffusion +
desorption) is approximately 20 s at 950 K, as measured with a
dedicated setup. In the MOT, we use 6 orthogonal Ti:sapphire laser
beams for the main pumping transition and 6 beams from a stabilized
diode repumper. Fluorescence from trapped atoms is observed with a
cooled CCD camera, in order to reach noise levels from stray
light equivalent to approximately 50 atoms. Systematic tests are
being done to improve the trapping efficiency. We plan to further
develop Fr traps at LNL; in parallel, we will study APNC and EDM
techniques and systematics with stable alkalis at Pisa, Siena, and
Ferrara. 相似文献
12.
L. Willmann 《Applied physics. B, Lasers and optics》1999,69(5-6):357-361
The recent creation of a Bose–Einstein condensate of atomic hydrogen has added a new system to this exciting field. The differences
between hydrogen and the alkali metal atoms require other techniques for the initial trapping and cooling of the atoms and
the subsequent detection of the condensate. The use of a cryogenic loading technique results in a larger number of trapped
atoms. Spectroscopic detection is well suited to measuring the temperature and density of the sample in situ. The transition
was observed at a temperature of 50 μK and a density of 2×1014 cm-3. The number of condensed atoms is about 109 at a condensate fraction of a few percent. A peak condensate density of 4.8×1015 cm-3 has been observed.
Received: 22 June 1999 / Published online: 3 November 1999 相似文献
13.
We have established a caesium double magneto-optical trap (MOT) system for
cavity-QED experiment, and demonstrated the continuous transfer of cold caesium
atoms from the vapour-cell MOT with a pressure of ~ 1×10-6 Pa to
the ultra-high-vacuum (UHV) MOT with a pressure of ~ 8×10-8 Pa via a
focused continuous-wave transfer laser beam. The effect of frequency detuning as
well as the intensity of the transfer beam is systematically investigated, which
makes the transverse cooling adequate before the atoms leak out of the vapour-cell
MOT to reduce divergence of the cold atomic beam. The typical cold atomic flux got
from vapour-cell MOT is ~2×107 atoms/s. About 5×106
caesium atoms are recaptured in the UHV MOT. 相似文献
14.
We present a high-power and narrow-linewidth laser for intercombination magneto-optical trapping of ytterbium (Yb) atoms using
the 6s2
1S0–6s6p 3P1 transition. The system generates 415 mW of continuous wave laser radiation at 556 nm with a linewidth of less than 100 kHz.
It is based on a commercial 1 W fiber laser with a frequency doubling stage. Up to 58% frequency doubling efficiency is obtained
at an input power of 0.5 W by using a lithium triborate crystal as a nonlinear medium. The system has been successfully used
for laser cooling of Yb atoms.
PACS 42.55.Wd; 42.60.By; 42.79.Nv 相似文献
15.
Cold atomic beam from a rubidium funnel 总被引:1,自引:0,他引:1
We report an experimental demonstration of a continuous, slow and cold beam of rubidium atoms from a two-dimensional magneto-optic
trap or atomic funnel. Typically 7.3(7)×108 atoms/s are ejected from the funnel with a variable velocity in the range 2–8 m/s and a temperature of 45–55 μK in the moving
frame. This represents the first demonstration of sub-Doppler laser cooling in an atomic beam and temperatures as low as ≈25 μK
have been observed.
Received: 30 September 1999 / Published online: 5 April 2000 相似文献
16.
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
17.
We report on the trapping of radioactive atoms for a variety of nuclear, atomic, and applied physics investigations. To date
we have trapped 5 different radioisotopes of rubidium and cesium (82–84Rb+135,137Cs) using a magneto-optical trap (MOT) coupled to a mass separator. By optimizing the efficiency of this system, we have been
able to trap as many as 6 million radioactive atoms and detect as few as 100. This technology is being applied in three different
areas: (1) the parity-violating, β-decay asymmetry measurement of polarized 82Rb; (2) the study of ultracold fermionic 84Rb atoms; and (3) the use of MOTs for the ultrasensitive detection of selected radioactive species. Although all of these
projects are in a formative stage of development, we highlight the progress that we have made in: (1) the trapping of 82Rb atoms in double MOT system; (2) the hyperfine structure measurement of the 5P1/2 and 5P3/2 levels in 82Rb; (3) the simultaneous trapping of 84Rb and 87Rb in overlapping MOTs; and (4) the first trapping and isotopic ratio measurement of 135Cs and 137Cs in a MOT.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
18.
We study the collective dynamics in a degenerate Bose–Fermi mixture of 174Yb and 173Yb atoms. We excite collective oscillations by a sudden reduction of the trapping confinement and observe low m=0 quadrupole oscillations of condensates in 174Yb. First the oscillations in 174Yb atoms alone are investigated, and they are well described by the time-dependent Gross–Pitaevskii equation in the Thomas–Fermi approximation. Using the same procedure the quadrupole oscillations are excited for a 174Yb–173Yb Bose–Fermi mixture. In comparing data taken with and without fermionic 173Yb atoms, the oscillation frequency of the quadrupole mode in the condensate decreases with the presence of 173Yb atoms. 相似文献
19.
为了制备适于原子干涉仪实验的低温锂原子样品,开展了锂原子的塞曼减速及与磁光阱囚禁相关的实验研究.设计并实现了一种结构紧凑的腔体内冷式多级线圈叠加的塞曼减速器,将速度小于600 m/s的7Li原子减速到60 m/s,磁光阱装载速率为5×108/s,囚禁原子数目1×109个,原子团的最低温度约为220±30μK.研究了光学黏胶中7Li原子的寿命与囚禁光频率失谐量的关系.这些结果为进一步开展7Li原子亚多普勒冷却、光势阱蒸发冷却以及原子干涉仪实验奠定了基础. 相似文献
20.
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