Alexis BONNIN will defend his PhD thesis , entitled “Dual-Species Atom Interferometry and Applications to Inertial Measurements”, which work was accomplished in ONERA . The defense will take place on Monday, 23 of November 2015 at 14:00 in Laboratoire Aimé Cotton (Salle Balmer), Orsay.
In the emerging issue of testing the Equivalence Principle with cold atom inertial sensors, this thesis focuses on the realization and the characterization of a simultaneous dual-species atom interferometer (87Rb & 85Rb) which allows to measure the diﬀerential acceleration in an extremely sensitive way. The Mach-Zehnder type atom interferometer relies on the simultaneous handling of atomic wave-packets with stimulated Raman transitions. The laser system is based on the frequency doubling of a single laser source at 1560 nm. All the required laser frequencies for handling both isotopes (trapping, cooling, selection, interferometry and detection) are generated by phase modulating this source. A detailed modeling of the interferometer’s inertial responses and an analysis of a method to extract the diﬀerential phase were carried out. The diﬀerential acceleration measurement led to an atom based test of the Weak Equivalence Principle of η( 87Rb, 85Rb) = (1.3 ± 3.2) × 10− 7, at the state-of-the-art. The simultaneous aspect of the experiment allowed to highlight for the ﬁrst time common mode vibration noise rejection with two diﬀerent atomic species, a rejection factor of 50 000 being currently achieved. The current performance of the instrument exhibits a sensitivity on the diﬀerential acceleration of 1.23 × 10− 7 g/sqrt(Hz) and a resolution of 2 × 10− 9 g for integration times lower than few hours. Finally, innovative operating modes of dual-species atom interferometers for on-board acceleration measurements are explored.