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New detection system based on light shift engineering for a cold-atom gyroscope

Application for a Master 2 internship with possibility to pursue a PhD thesis

M2 internship (6 months, starting in February or March 2020)

Laboratory : SYRTE – Observatoire de Paris, 77 avenue Denfert Rochereau, 75014 Paris, France

Supervisor : Remi GEIGER, remi.geiger@obspm.fr ; +33(0)1.40.51.22.08

Website : https://syrte.obspm.fr/spip/science/iaci/

Asbtract: Inertial sensors with cold atoms offer many applications in fundamental physics (tests of the laws of gravitation, gravitational astronomy), geosciences (measurements of the gravity field or of Earth rotation) and inertial navigation (inertial units). The operation of these sensors is based on atomic interferometry taking advantage of superpositions between quantum states of different momentum of an atom. These superposition states are obtained by means of optical transitions with two (or more) photons communicating momentum to the atom and acting as separating plates and mirrors for the matter waves. SYRTE is a pioneer laboratory of the field, recognized worldwide for its expertise in the metrology of these quantum sensors, their use for different applications, and their technological transfer.

The aim of this internship is to contribute to the development of a new cold atom gyroscope currently operated at SYRTE. In order to increase the sampling rate of the gyroscope for future applications (in particular in seismology), the detection system must be modified in order to reduce the impact of the light scattered by the detected atoms on the atoms in the interferometer. To this aim, the new detection system will introduce differential light shifts (AC Stark shift) between the ground 6S_1/2 state and the excited 6P_3/2 state through the use of an auxiliary laser at 917 nm. A new laser system will be developed for this purpose. The work will include the stabilization of this laser on the reference laser (at 852 nm to manipulate Cesium atoms) with a transfer cavity, and the realization of the optical systems to combine the 852 and 917 nm lasers, intended to be directed onto the atoms.

In the case of a continuation as a PhD student, this laser system will be implemented on the gyroscope experiment to test its effectiveness on the immunity of the interferometer to the detected light.

References : R. Geiger et al, AVS Quantum Sci. 2, 024702 (2020) ;  L. Sidorenkov et al, Phys. Rev. Lett. 125, 213201 (2020) ; D. Savoie et al, Science Advances, eaau7948 (2018);

Key words: atom interferometry, inertial sensor, cold atoms.

Required skills: optics and lasers, instrumentation, atomic physics, data analysis; ability to work in a team.