PhD defense of Fabien Théron : “Development of a cold atom gravity gradiometer and a telecom doubled laser device for onboard applications”

Fabien Théron will defend his PhD thesis , entitled “Development of a cold atom gravity gradiometer and a telecom doubled laser device for onboard applications”, which work was accomplished in ONERA . The defense will take place on Friday, Friday, 27 of November 2015 at 14:00 in Institut d’Optique Graduate School (Auditorium), Palaiseau.

Summary :

This thesis presents the development of the experimental setup allowing the measurement of two gravity gradient components and the gravity acceleration. These quantities are resulted from the measuring of rubidium cold atoms acceleration, in free fall in vacuum, by atom interferometry. For gradiometry, the differential measurement is realized between two atomic clouds spatially separated. For the measurement of vertical gradient, the use of mobile optical lattices allows to get two atom clouds from a single atomic source.

This work presents the setting up of the complete device, in particular with the built of the vaccum chamber, laser and micro-wave systems. Lasers are based on frequency-doubled telecom technology, which allows to obtain compact and robust systems, dedicated for onboard applications. The innovative laser architecture allows to combine atom interferometry and optical lattices, while minimizing the amount of components. The laser noise has been characterized, and limits the single shot gravimetric sensitivity to 10-9 g, the single shot differential sensitivity to 10-10 g, and the single shot gradiometric sensitivity to 38 E.