On-Atom Chip Inertial Sensing – OnACIS

On-Atom Chip Inertial Sensing
Keywords : Atom interferometry; inertial sensors; cold atoms; atom chips;
Partners: Systèmes de Référence Temps-Espace (SYRTE), Thales Research&Technology France (TRT)
Requested grant: 300 000€
Project starting and ending dates: 2014 - 2017

The main goal of this project is to tackle the limits for inertial sensing using compact atom interferometers based on cold atom manipulation in atom chips. Our work will be essentially concentrated on the development and characterization of atom chip matter-wave interferometers for acceleration and rotation sensing. As compared to state-of-the-art atomic sensors, which typically use free-falling atoms, atom chip sensors would be more compact, while potentially keeping the high level of performance associated with cold atoms. The longer term objective supported by this project is the achievement of a compact atom chip based high-performance inertial measurement unit (IUM) hybridized with microelectromechanical (MEMS) sensors for higher measurement bandwidth. We will take into account the possibility of such hybridization from the very beginning of the project (at both hardware and software levels) in cooperation with experts from Thales Avionics.

Such a compact high-performance IMU could find applications in several military systems usually relying on Global Navigation Satellite Systems, when the latter are not available (technical failure, urban canyon, intentional jamming…). Other possible applications are high performance inertial navigation with a compact IMU, terrain correlation with gravity sensing and several kinds of scientific applications.

At the heart of the scientific project is the study and implementation of coherent beam splitters, and the investigation of different sources of decoherence in an atom chip interferometer, whether they are of technical or physical nature. In particular, we will investigate two very promising ways of implementing on-atom chip beam splitters, namely radiofrequency manipulation of the external degree of freedom of magnetically guided atoms and microwave manipulation of both internal and external degrees of freedom of magnetically trapped atoms. From the technology point of view, two different materials employed in the fabrication of atom chips (SiC and AlN) will be compared in terms of adequacy for the fabrication of inertial sensors. We will extensively study the technical issues leading to decoherence in atom chip interferometry, such as the roughness of the magnetic guide in guided atom interferometry and current noise leading to the fluctuations of trapping frequencies in trapped atom interferometry. From a physics point of view, we will address the questions of using sub-Doppler cooled thermal and Bose-Einstein condensed atoms for inertial sensing with guided and trapped atoms, the interaction induced decoherence, and the role of interatomic correlations.

At the end of this project, we plan to establish a technology roadmap for the industrial development of a inertial sensors based on the hybridization of atom chips and MEMS sensors, which would be a technological breakthrough in the field.