High contrast Mach-Zehnder lithium atom interferometer in the Bragg regime

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 atom interferometers. This apparatus will be applied to high sensitivity measurementsComment: 6 pages, 3 figures, accepted by Appl. Phys.

Optimization of a Langmuir-Taylor detector for lithium

This paper describes the construction and optimization of a Langmuir-Taylor detector for lithium, using a rhenium ribbon. The absolute detection probability of this very sensitive detector is measured and the dependence of this probability with oxygen pressure and surface temperature is studied. Sources of background signal and their minimization are also discussed in details. And a comparison between our data concerning the response time of the detector and literature values is given. A theoretical analysis has been made: this analysis supports the validity of the Saha-Langmuir law to relate the ionization probability to the work function. Finally, the rapid variations of the work function with oxygen pressure and temperature are explained by a chemical equilibrium model.Comment: 11 pages, 7 figures, to appear in Rev. Sci. Instru

Planck's scale dissipative effects in atom interferometry

Atom interferometers can be used to study phenomena leading to irreversibility and dissipation, induced by the dynamics of fundamental objects (strings and branes) at a large mass scale. Using an effective, but physically consistent description in terms of a master equation of Lindblad form, the modifications of the interferometric pattern induced by the new phenomena are analyzed in detail. We find that present experimental devices can in principle provide stringent bounds on the new effects.Comment: 12 pages, plain-Te

Atomic diffraction by a laser standing wave: Analysis using Bloch states

Atomic diffraction by a laser stationary wave is commonly used to build mirrors and beam splitters for atomic interferometers. Many aspects of this diffraction process are well understood but it is difficult to get an unified view of this process because it is commonly described in several approximate ways. We want to show here that a description inspired by optics and using the exact Bloch description of the atomic wave inside the laser standing wave is a tutorial way of describing the various regimes by a single formalism. In order to get simple analytic expressions of the diffraction amplitudes, we consider a standing wave intensity with a flat transverse profile. The resulting general expression of the diffraction intensities is then compared to available analytical formulae in the Raman-Nath limit and in the Bragg regime. We think that this formalism can be fruitfully extended to study many important questions

Diffraction phases in atom interferometry

Using Bloch states to describe atomic motion, we show how to calculate the phase shifts associated to atomic diffraction by a laser standing wave and we illustrate our calculation by the evaluation of the phase shifts in the contrast interferometer developed by D. Pritchard and co-workers [Phys. Rev. Lett. 89, 140401 (2002)]

An atom interferometer using thermal lithium atoms

We have built an atom interferometer of the Mach-Zehnder type, operating with thermal lithium atoms [1]. Its design is largely inspired by previous works done by the groups of D. Pritchard [2], A. Zeilinger [3] and S.A. Lee [4]. In our apparatus, the atomic wave is diffracted in the Bragg regime by three laser sanding waves to achieve a Mach-Zehnder configuration. This paper briefly recalls the diffraction process and shows the experimental results obtained in our group. Our apparatus is able to achieve a high fringe contrast of 74 % with a large mean detected atom flux of $1.5 \times 10^{4}$s$^{-1}$. Finally, the paper ends with the measurement of the velocity distribution of our lithium beam using a light induced fluorescence technique