13th of December 2018 (Paris) – PhD defense of Grégoire Vallet

Grégoire VALLET will defend his thesis on 13th of December 2018 at 2:00 pm on the subject “Cavity assisted non destructive detection on a strontium optical lattice clock”, realized in SYRTE, under the supervision of Sébastien Bize and co-supervised by Jérôme Lodewyck.

The defense will take place in room 235A (2nd floor) at ENS, 29 rue d’Ulm 75005 Paris, in front of a jury composed of Caroline Champenois, Robin Kaiser, Jakob Reichel and Morgan Michell.


I will start depicting the current landscape of atom clocks research providing you with the fundamental mechanisms, concepts and tools as well as the issues and challenges of the field, along with a detailed presentation of the working of the strontium optical lattice clock I have been working on during my training.
In a second step I will address the metrological aspect of my activity: evaluations of systematics effects inducing clock frequency shifts and participations to continental scale fiber links clock comparison campaigns. After presenting our most recent uncertainty budget I will expose our preliminary results in exploring one of these effects that we are the first group to report on in the case of strontium clocks and to include in our budget: the clock frequency shift induced by collisions between trapped strontium atoms and hot particles of background residual gas. I will as well expose the model I worked out for addressing this issue which unifies the two incompatible models available in the literature.
Finally I will discuss the research and experimental aspects of my work focused on the achievement of a non destructive detection system of atoms in cavity based on dispersive features of light-matter interaction, aiming at the reduction of two effects detrimental to optical lattice clocks stability: Dick effect and quantum projection noise. I will give as well prospects on the metrological gains expected from such technique.