Improving the stability and accuracy of a cold atom gyroscope using real-time control methods

This thesis consists of the implementation and study of new experimental techniques to improve the performance of the SYRTE’s dual-axis cold atom gyroscope experiment. The instrument represents the state of the art of matter wave gyroscopes and uses stimulated Raman transitions to perform a 4-pulse interferometer. This geometry results in a Sagnac area of 11 cm² for 800 ms interrogation time.

In this thesis, we detail a fundamental physics test with the cold-atom gyroscope which consists of a validity test of the Sagnac Effect with a matter-wave interferometer. The results from a year-long experimental campaign are presented, demonstrating a 20-fold improvement in accuracy over previous efforts in measuring the gyroscope scale factor, and corresponding to a 23 ppm accuracy level.

Additionally, this work also discusses two novel real-time methods to control the phase of the interferometer using Raman frequency jumps and mirror position jumps rather than using Raman laser’s relative phase jump. We provide a thorough description of both methods and delve into the particulars of their physical implementation, which is also characterized in detail. A comparative analysis of the performance of these two methods is also presented.

This work opens the path for the possibility of real time atomic phase compensation to any atom interferometer based on two photon transitions for the atomic wave diffraction and in particular when using Raman double diffraction regime for space applications.

atom interferometry, inertial sensor, cold atoms, test of fundamental physics

Full document (EN) : HAL-04346752