Investigation of inertial sensing using electromagnetically induced transparency

Abstract

Measuring the motion of quantum particles has been playing a significant role in performing high precision inertial sensing and studying fundamental physics. While most of the motion sensing schemes with cold atoms are based on single-particles. In this thesis, a new measuring method of using a collective state of atoms for motion quantum sensing is introduced. Two experiments were demonstrated to investigate its feasibility. One is related to the light-dragging effect in an electromagnetically induced transparent (EIT) cold 85Rb atomic ensemble. The dragging coefficient Fd was enhanced to 1.67*10^3 , which was three orders of magnitude better than the previous experiments. With a large enhancement of the dragging effect, we realised an atom-based velocimeter that has a sensitivity of 1 mm/s, which was two orders of magnitude higher than the velocity width of the atomic medium used before. Such a demonstration could pave the way for motion sensing using the collective state of atoms in a room temperature vapour cell or solid-state material. Another experiment is related to the motion sensing in a driven periodic potential. The motion of the atomic ensemble undergoing Bloch oscillation was measured using the light dragging method. In order to have efficient Bloch oscillation of atoms, the first Raman sideband cooling of 85Rb to pre-cool atomic ensemble close to the recoil temperature (357 nK) was achieved by us. The phase shift measurements showed the linear-like relation to the accelerating time with the data precision 0.00036 rad (0.005 ns, 0.7 mm/s), instead of the stepwise oscillation period . To observe the stepwise motion, it is required to reduce the lattice field intensity and implement the velocity selection technique to select atoms with a narrow velocity width.