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1.
+ ions. The Ca+ ions are trapped in a miniature rf Paul trap and irradiated by light from a frequency-doubled diode laser at 397 nm and by
light from a diode laser at 866 nm. We are able to cool a single ion and observe its fluorescence continuously with the laser
diode locked to the external frequency-doubling cavity. Quantum jumps in the fluorescence light of a single ion and of a small
cloud of five ions have been induced by driving the “clock” transition at 729 nm. We were able to resolve the influence of
the micromotion on the excitation spectrum of the small ion cloud.
Received: 10 July 1997/Revised version: 17 November 1997 相似文献
2.
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
3.
An endcap ion trap is described for trapping and laser cooling of a single strontium-88 ion. The 422 nm cooling laser is offset locked to the Doppler-free 5s 2S1/2(F′′=2)–6p 2P1/2(F′=3) transition in 85Rb using saturation spectroscopy. The peak fluorescence signal from a single ion is around 6.0×104 counts/s with the cooling laser at saturation intensity. Optical pumping of the ion in zero magnetic field is eliminated by the use of two 1092 nm repumper laser beams incident on the ion to create a time-varying polarisation. The ion’s micromotion can be reduced in all three dimensions, and the motional sidebands on the weak 5s 2S1/2–4d 2D5/2 quadrupole transition in 88Sr+ have been observed. These results show the ion to be confined to less than a wavelength in three dimensions. 相似文献
4.
Measurement of Secular Motion Frequency in Miniature Paul Trap to Ascertain the Stability Parameters
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40Ca+ ions are trapped and laser cooled in a miniature Paul trap. The secular motion was observed by the radio-frequency resonance of the ion cloud and Zeeman profile sidebands of a single ion experimentally. The trap stability parameters a and q are determined with an uncertainty under 1% by the secular motion frequency measurement. The trap efficiency is 0.75. A practicable suggestion is given for the benefits of a new trap design. 相似文献
5.
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
6.
S. Urabe M. Watanabe H. Imajo K. Hayasaka U. Tanaka R. Ohmukai 《Applied physics. B, Lasers and optics》1998,67(2):223-227
1/2 -D5/2 electric-quadrupole-allowed transitions of a laser-cooled Ca+ ion in a small rf trap. The electron shelving method was used to measure the absorption spectrum of the electric-quadrupole-allowed
transitions, and the motional sidebands due to the secular motion of the ion in the harmonic potential well of the rf trap
were completely resolved. The effective temperature of the ion, estimated by comparing the observed sideband intensities with
the theoretical ones, was less than 4.4 mK. This result is in good agreement with that obtained from the analysis of the linewidth
measurement.
Received: 18 March 1998 相似文献
7.
H. Imajo S. Urabe K. Hayasaka M. Watanabe R. Hayashi 《Applied physics. B, Lasers and optics》1993,57(2):141-144
Be+ ions stored in a Penning trap were cooled by a laser beam perpendicular to the magnetic field. The cooled ions are strongly coupled and phase transitions of up to 100 ions were observed. In experiments with only a few ions stored in the trap, a stepwise decrease in fluorescence intensity was observed. All steps are of the same size and so every step is attributed to a single ion. The discrete changes in fluorescence occurred more frequently when the background pressure was increased, caused by collisions between stored ions and background neutral molecules. 相似文献
8.
Ion synthesis and laser annealing of Cu nanoparticles in Al2O3 总被引:1,自引:0,他引:1
A.L. Stepanov V.N. Popok D.E. Hole I.B. Khaibullin 《Applied Physics A: Materials Science & Processing》2002,74(3):441-446
Al2O3 samples with Cu nanoparticles, synthesised by ion implantation at 40 keV with a dose of 1×1017 ion/cm2 and a current density from 2.5 to 12.5 μA/cm2, were annealed using ten pulses from a KrF excimer laser with a single pulse fluence of 0.3 J/cm2. The copper depth distribution, formation and modification of metal nanoparticles under the ion implantation and laser treatment
were studied by Rutherford backscattering (RBS), energy dispersive X-ray (EDX) analysis, atomic force microscopy (AFM) and
optical spectroscopy. It was found that laser annealing leads to a reduction in the nanoparticle size without diffusion of
metal atoms into the bulk. The change in particle size and the possibility for oxidation of the copper particles are examined
in the framework of Mie theory. Calculations presented show that under excimer laser treatment, Cu nanoparticles are more
likely to be reduced in size than to undergo oxidation.
Received: 19 April 2001 / Accepted: 7 November 2001 / Published online: 23 January 2002 相似文献
9.
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
10.
85 Rb, 5s2S1/2(F”=2)→6p2P1/2(F’=2,3) absorption resonance with the 88Sr+, 5s2S1/2→5p2P1/2 transition is exploited to provide a simple, effective frequency reference for a laser cooling/fluorescence excitation source
applied to single Sr+ ions. A modulation-free frequency stabilization system has been designed which uses the differential signal from two frequency-displaced
beams traversing a Rb cell and which probe the Doppler-broadened Rb S–P lineshape at microwatt power levels. The method is
applied to frequency lock a 422-nm frequency-doubled diode laser system that is used for excitation of a single 88Sr+ ion. Stable, long-term laser cooling and fluorescence are achieved using the frequency-stabilized 422-nm source resulting
in observed ion confinement times without adjustment of over 8 h, together with an improvement in single-ion loading efficiency.
Received: 12 February 1998 相似文献
11.
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
12.
M. Block O. Rehm P. Seibert G. Werth 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,7(3):461-465
We have measured the lifetime of the metastable 3D
5/2
level in Ca+ using the “quantum jump" technique on a single stored and laser cooled ion in a linear Paul trap. We found a linear dependence
of the measured decay rate on the power of the laser which repumps the ions from the long lived 3D
3/2
level. This can be explained by off-resonant depletion of the 3D
5/2
level. The proper lifetime of this level is obtained by a linear extrapolation of the measured lifetime to zero laser power.
We obtain 1100(18) ms in agreement with theoretical calculations. The observed systematic change of the decay rate resolves
discrepancies between earlier experiments in which this effect had not been considered. Measurements on a linear chain of
10 laser cooled ions showed unexpected frequent coincidences of quantum jumps within our observation time of 20 ms. This indicates
a so far unexplained correlation between the ions in the chain at large distances.
Received 3 March 1999 相似文献
13.
E. Kirilov S. Putterman 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,54(3):683-691
We describe an efficient way to photoionize strontium atoms in a linear radio-frequency trap. We use a 2-photon second order
process to excite the autoionization resonance (4d2+5p2) 1D2 in neutral strontium (Sr). A doubled Ti:sapphire laser system is used at 431 nm to provide 100 fs pulses at 82 MHz. The fabrication
of the laser systems for addressing the Sr+ transitions necessary for laser cooling and excitation of quantum jumps, vacuum system and ion trap structure are also described.
With the current setup a easy and repeatable trapping of linear ion chains is readily achieved at very low Sr vapor pressures. 相似文献
14.
Ph.W. Courteille S.R. Muniz K. Magalhães R. Kaiser L.G. Marcassa V.S. Bagnato 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,15(2):173-180
Neutral atoms may be trapped via the interaction of their magnetic dipole moment with magnetic field gradients. One of the possible schemes is the cloverleaf
trap. It is often desirable to have at hand a fast and precise technique for measuring the magnetic field distribution. We
use for instantaneous imaging the equipotential lines of the magnetic field a diagnostic tool which is based on spatially
resolved observation of the fluorescence emitted by a hot beam of sodium atoms crossing a thin slice of resonant laser light
within the magnetic field region to be investigated. The inhomogeneous magnetic field spatially modulates the resonance condition
between the Zeeman-shifted hyperfine sublevels and the laser light and therefore the amount of scattered photons. We apply
this technique for mapping the field of our cloverleaf trap in three dimensions under various conditions.
Received 20 March 2001 and Received in final form 12 May 2001 相似文献
15.
S. Urabe K. Hayasaka M. Watanabe H. Imajo R. Ohmukai R. Hayashi 《Applied physics. B, Lasers and optics》1993,57(5):367-371
This paper describes trapping and laser cooling of a Ca+ ion in an rf quadrupole ion trap. A single Ca+ ion is laser cooled to below 130 mK and quantum jumps are observed by exciting the ion into the metastable D
5/2 state via the P
3/2 state. The lifetime of the metastable D
5/2 state is estimated from the distribution of the dark periods of the quantum-jump signal. Collision-induced jumps between the metastable D
3/2 state and the D
5/2 state in a background gas are also directly observed. 相似文献
16.
F. Pereira Dos Santos F. Perales J. Léonard A. Sinatra Junmin Wang F. Saverio Pavone E. Rasel C.S. Unnikrishnan M. Leduc 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,14(1):15-22
We present experimental results on the two-body loss rates in a magneto-optical trap of metastable helium atoms. Absolute
rates are measured in a systematic way for several laser detunings ranging from -5 to -30 MHz and at different intensities,
by monitoring the decay of the trap fluorescence. The dependence of the two-body loss rate coefficient β on the excited state
( 23
P
2) and metastable state ( 23
S
1) populations is also investigated. From these results we infer a rather uniform rate constant K
sp = (1±0.4)×10-7 cm3/s.
Received 8 September 2000 and Received in final form 19 December 2000 相似文献
17.
A single ^40Ca^+ ion is loaded in a miniature Paul trap and the probability of directly loading a single ion is above 50%. The signal-to-noise ratio and the storage time for a single ion have been improved by minimizing the ion micromotion and locking a 397nm cooling laser to a Fabry-Perot interferometer and optogalvanic signal. From the fluorescence spectrum, the ion temperature is estimated to be about 5mK. 相似文献
18.
I. A. Semerikov K. Yu. Khabarova I. V. Zalivako A. S. Borisenko N. N. Kolachevsky 《Bulletin of the Lebedev Physics Institute》2018,45(11):337-340
The schematic diagram of the compact transportable optical frequency standard based on the quadrupole transition in a single 171Yb+ ion with a relative instability at the levelx of 5 · 10?16, less than 1m3 in volume and less than 300 kg in weight is presented. The ionic trap and laser systems are described. Trapping and laser cooling of the 174Yb+ ion are experimentally demonstrated. 相似文献
19.
A diode-laser optical frequency standard based on laser-cooled Ca atoms: Sub-kilohertz spectroscopy by optical shelving detection 总被引:2,自引:0,他引:2
C.W. Oates F. Bondu R.W. Fox L. Hollberg 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,7(3):449-460
We report an optical frequency standard at 657 nm based on laser-cooled/trapped Ca atoms. The system consists of a novel,
compact magneto-optic trap which uses 50 mW of frequency-doubled diode laser light at 423 nm and can trap >107 Ca atoms in 20 ms. High resolution spectroscopy on this atomic sample using the narrow 657 nm intercombination line resolves
linewidths (FWHM) as narrow as 400 Hz, the natural linewidth of the transition. The spectroscopic signal-to-noise ratio is
enhanced by an order of magnitude with the implementation of a “shelving" detection scheme on the 423 nm transition. Our present
apparatus achieves a fractional frequency instability of in 1 s with a potential atom shot-noise-limited performance of and excellent prospects for high accuracy.
Received 2 November 1998 相似文献
20.
L. Santos M. Lewenstein 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,7(3):379-390
We study a dynamical scheme for condensation of bosonic trapped gases beyond the Lamb-Dicke limit, when the photon-recoil
energy is larger than the energy spacing of the trap. Using quantum master equation formalism we demonstrate that dark-state
cooling methods similar to those designed for a single trapped atom allow for the condensation of a collection of bosons into
a single state of the trap, either the ground, or an excited state. By means of Monte-Carlo simulations we analyse the condensation
dynamics for different dimensions, and for different cooling schemes.
Received 30 November 1998 and Received in final form 20 March 1999 相似文献