Orateur
Description
Rydberg atoms are atoms excited to states with a very high principal quantum number, where the valence electron orbits very far from the nucleus. This large distance imparts exceptional properties to Rydberg atoms compared to ordinary atoms, which has made them central to many developments and applications of modern experimental quantum physics. In particular, they exhibit transitions in the radiofrequency (RF) and terahertz (THz) domains with very large dipole matrix elements, making them extremely sensitive to electromagnetic fields in these frequency domains. This has led over the last ten years to the emergence of a new technology of RF and THz field sensors, where the amplitude of the field is measured by performing electromagnetically induced transparency spectroscopy of the Autler-Townes doublet induced by the interaction between the field and Rydberg states of atoms in a thermal vapor. Such sensors offer several advantages over classic antennas, including a high sensitivity, a wider frequency range, a size independent from the frequency of the measured field, a significantly reduced need for calibration, and the ability to measure, in addition to the amplitude, the frequency, the phase and the polarization. All these benefits make Rydberg atoms-based RF field sensors excellent candidates for applications in telecommunications, radar systems, and the space sector. Currently, these sensors are the subject to numerous works aiming at improving their performance in terms of sensitivity and accuracy. The use of cold atoms instead of thermal vapors represents a promising avenue in these goals, due to their better coherence and strongly reduced Doppler effect. Additionally, cold atoms are suitable for other forms of spectroscopy that are potentially more robust in certain aspects. This seminar is about the study (carried out during my PhD) of another measurement method possible with cold atoms: the trap-loss spectroscopy of the Autler-Townes doublet. After having made a state of the art of Rydberg atoms based-sensors, we will see what trap-loss spectroscopy is and how it works, and then we will broach the results of the study of the metrological performance of this method applied to RF field sensing.
