R. Delhuille

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

Abstract.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.

Optimization of a Langmuir–Taylor detector for lithium

This article 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 detail. 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.

Matter Neutrality Test Using a Mach-Zehnder Interferometer

Neutrality of atoms and neutrons is already well established, with upper limits on the residual charge close to 10-21|qe| where qe is the electron charge. The present paper proves that the sensitivity of atom interferometry is sufficient to compete with these previous measurements, with the additional advantage of dealing with single isolated particles. An experiment involving a three grating Mach-Zehnder atom interferometer using Bragg diffraction on laser standing waves and a slow lithium atomic beam is discussed with some details. Its sensitivity and the systematic effects due to atomic polarisability are evaluated carefully.

Computation of the phase induced by non-Newtonian gravitational potentials in atom interferometry

In this letter we present a computation of the phase induced by source masses of different geometries, in the framework of non-Newtonian gravitation, on an idealized separated arms atom interferometer. We deduce the related limits on the non-Newtonian gravitational strength in the sub-millimetre region for the potential range. These limits would be comparable with the best existing experimental limits but with the advantage of using a microscopic probe.

Atom interferometry: Principles and applications to fundamental physics

The first part of this contribution presents an overview of atom interferometry. In a second part, we discuss in greater details the sensitivity of such experiments to weak perturbations and their application to direct test of the electric neutrality of atoms with extreme precision.