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1.
射频囚禁离子被广泛应用于量子信息和冷分子制备. 对于从单个离子到10^6个离子不等的样品,这些原子的内能和外能可以被控制到非常高的精度. 重点讨论了利用射频囚禁的Ca+来作为频率计量的标准方法. 相似文献
2.
G. Bazalgette M. Büchner C. Champenois G. Trenec J. Vigué 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,6(2):193-200
We describe the first saturation spectroscopy experiment concerning the A-X transition of ICl with considerably better resolution
than previous works. Form our data, improved constants for the hyperfine structure of the excited state are determined. The
A-X transition of ICl could be used to develop a set of secondary frequency standards and its metrologic qualities are discussed.
Received: 27 July 1998 / Received in final form: 30 November 1998 相似文献
3.
Radiofrequency (rf) trapped ions are versatile candidates for a large panel of applications ranging from quantum information to the creation of cold molecules. Sample size can range from a single to 10^6 ions, and the internal and external energy states of the atoms can be controlled with high precision. In the experiment, we focus on different protocols related to frequency metrology using rf trapped Ca. 相似文献
4.
M. Marciante C. Champenois A. Calisti M. Knoop 《Applied physics. B, Lasers and optics》2012,107(4):1117-1123
A small number of laser-cooled ions trapped in a linear radiofrequency multipole trap forms a hollow tube structure. We have studied, by means of molecular dynamics simulations, the structural transition from a double ring to a single ring of ions. We show that the single-ring configuration has the advantage to inhibit the thermal transfer from the rf-excited radial components of the motion to the axial component, allowing ions to reach the Doppler limit temperature along the direction of the trap axis. Once cooled in this particular configuration, the ions experience an angular dependency of the confinement if the local adiabaticity parameter exceeds the empirical limit. Bunching of the ion structures can then be observed and an analytic expression is proposed to take into account for this behavior. 相似文献
5.
C. Lisowski M. Knoop C. Champenois G. Hagel M. Vedel F. Vedel 《Applied physics. B, Lasers and optics》2005,81(1):5-12
Single, rf-trapped ions find various applications ranging from metrology to quantum computation. High-resolution interrogation of an extremely weak transition under best observation conditions requires an ion almost at rest. To avoid line-broadening effects such as the second-order Doppler effect or rf heating in the absence of laser cooling, excess micromotion has to be eliminated as far as possible. In this paper the motional state of a confined three-level ion is probed, taking advantage of the high sensitivity of observed dark resonances to the trapped ion’s velocity. Excess micromotion is controlled by monitoring the dark-resonance contrast with varying laser-beam geometry. The influence of different parameters such as the cooling laser intensity has been investigated experimentally and numerically. 相似文献
6.
A scheme for a terahertz frequency standard based on three-photon coherent population trapping in stored ions is proposed. Assuming the propagation directions of the three lasers obey the phase matching condition, we show that stability of few 10(-14) at 1 s can be reached with a precision limited by power broadening to 10(-11) in the less favorable case. The referenced terahertz signal can be propagated over long distances, the useful information being carried by the relative frequency of the three optical photons. 相似文献
7.
C. Champenois M. Knoop M. Herbane M. Houssin T. Kaing M. Vedel F. Vedel 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,15(1):105-111
Frequency standard applications and ultra-high resolution spectroscopy of a confined single ion require traps of drastically
reduced dimensions (about or below 1 mm). These small dimensions increase the sensitivity of the trapping behavior to imperfections
in the trap geometry and to patch potentials. For the aim of the metrological laser interrogation of a single Ca+ ion, a miniature cylindrical ring trap was built. In order to optimize the laser cooling process and to reach strong binding
conditions, the boundaries of the stability diagram and the zones of low confinement as well as the ion motion properties
were characterized.
Received 14 November 2000 and Received in final form 1st February 2001 相似文献
8.
C. Champenois M. Büchner J. Vigué 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,5(3):363-374
Several three-grating Mach-Zehnder atomic interferometers have been built and operated in recent years but no general theory
of the contrast of the fringes produced by these apparatus is available. The purpose of this paper is to develop this theory,
based on the Fresnel-Kirchoff approximate treatment of diffraction. Such a theory has been developed by Turchette et al. [JOSA B 9, 1601 (1992)] but because the necessary multiple integrals were evaluated in a purely numerical way, this treatment was not
fully general. We show here how to reduce the computation by analytic means and we are thus able to calculate the contrast
with a modest numerical effort. Moreover, we get a simple insight of the contrast reduction related to several defects of
a real apparatus. We apply our calculations to existing interferometers as well as to an apparatus working with lithium which
is under construction in our laboratory.
Received: 24 April 1998 / Revised: 25 October 1998 / Accepted: 11 December 1998 相似文献
9.
R. Delhuille C. Champenois M. Büchner L. Jozefowski C. Rizzo G. Trénec J. Vigué 《Applied physics. B, Lasers and optics》2002,74(6):489-493
We have constructed an atom interferometer of the Mach–Zehnder type, operating with a supersonic beam of lithium. Atom diffraction
uses Bragg diffraction on laser standing waves. With first-order diffraction, our apparatus has given a large signal and a
very good fringe contrast (74%), which we believe to be the highest ever observed with thermal atom interferometers. This
apparatus will be applied to high-sensitivity measurements.
Received: 22 November 2001 / Revised version: 10 February 2002 / Published online: 24 April 2002 相似文献
10.
Jean-Baptiste Champenois Celine Cau Dit Coumes Arnaud Poulesquen Patrick Le Bescop Denis Damidot 《Rheologica Acta》2013,52(2):177-187
A specific cell was designed to monitor simultaneously the evolution of the viscoelastic properties, electrical conductivity, and temperature of a cement paste with ongoing hydration. Hydration of calcium sulfoaluminate cement by demineralised water or by a borated solution was then investigated as an example. Borate anions acted as set retarders but to a smaller extent than with ordinary Portland cement. The delay in cement hydration resulted from the precipitation of an amorphous or poorly crystallized calcium borate, which also caused a rapid stiffening (and thus a loss of workability) of the paste after mixing. The gypsum content of the CSA cement was shown to play a key role in the control of the cement reactivity. 相似文献