STAGE ULTRA COLD ATOM GRAVIMETER

Date de mise à jour de l’offre

SYRTE - Observatoire de Paris :

Situé à l’Observatoire de Paris, le SYRTE - Systèmes de Référence Temps-Espace - est une unité mixte de recherche (UMR 8630) du CNRS, de l’Observatoire de Paris - Université PSL et de Sorbonne Université. Alliant recherche de très haut niveau et services scientifiques, le SYRTE se place aujourd’hui au premier rang international dans des champs disciplinaires variés : métrologie du temps et des fréquences, systèmes de référence célestes, rotation de la Terre, histoire de l’astronomie. La pluridisciplinarité du SYRTE se retrouve aussi dans ses compétences transverses - théorie, instrumentation, traitement et analyse de données - et dans la diversité de ses objectifs qui vont de la physique fondamentale jusqu’au transfert industriel.

Description de la mission

Our team at SYRTE develops inertial sensors (accelerometers, gyrometers, …) based on atom interferometry technics. The development of this technology is linked to the use of cold atoms and laser beamsplitters, namely two photon transitions and more specifically stimulated Raman transitions. These methods allow now forthe development of commercial products with applications in geophysics on the field, and of onboard instruments in ships or planes for inertial navigation and geoscience.

We have developed at SYRTE a state of the art cold atom gravimeter (CAG), based on these techniques. It uses free falling 87Rb atoms, which experience a sequence of Raman pulses driven by counter-propagating vertical lasers. The atom interferometer phase shift is proportionnal to g, the Earth gravity acceleration. Our instrument measures g with a sensitivity better than conventionnal state of the art absolute gravimeters (5.7ng@1s) and is more accurate (2ng).

Limits have been identified and several improvements will be made to reach the CAG in the 10-10 g domain both in term of accuracy and sensitivity.

The vacuum chamber will be modified to allow to use a new crossed dipole trap with a 50W laser at 1.1µm. As during this operation the chamber will be opened, we will take advantage to install a new Raman reflexion system which will rotate high optical quality Raman mirror to drive the atoms. Moreover, new MOT beams will be used and powered locked with an innovative fiber splitter to control the initial cloud position.

The intern will integrate the team and the project as it progresses. The internship can range from (i) the implementation and optimization of the optical trap to (ii) the characterization and optimization of the reflexion system and/or (iii) the implementation and tests of the locked MOT source.
The ultimate aim is to improve the evaluation of Coriolis acceleration and wavefront distortions effects even further, by performing measurements at very low temperature, and with more atoms. This will require to optimizse the evaporation sequence, by increasing the capture volume of the trap using modulation techniques. Yet, a drawback when using dense samples of ultracold atoms, eventually Bose-Einstein condensed, instead of a more dilute laser cooled source, arises from the effect of interatomic interactions, which are expected in our configuration to impart small biases to the measurement.

Profil recherché

Etudiant M2

Niveau de qualification requis

Bac + 4/5 et +
  • Employeur
    SYRTE - Observatoire de Paris
  • Secteur d’activité de la structure
    Enseignement - Formation - Recherche
  • Effectif de la structure
    De 51 à 250 salariés
  • Site internet de la structure
    https://syrte.obspm.fr
  • Type de stage ou contrat
    Stage pour lycéens et étudiants en formation initiale
  • Date prévisionnelle de démarrage
  • Durée du stage ou contrat
    Plus de 4 mois et jusqu'à 6 mois
  • Le stage est-il rémunéré ?
    Oui
  • Niveau de qualification requis

    Bac + 4/5 et +
  • Lieu du stage
    61, avenue de l’Observatoire,
    75014 PARIS 14E ARRONDISSEMENT
  • Accès et transports
    https://syrte.obspm.fr/spip/presentation/article/acces-au-site-de-l-observatoire-de-paris