A leap towards quantum inertial sensing for onboard applications with atom interferometry

Published on August 2, 2024 – News

The hybrid rotating atom interferometer in the experiment room of iXAtom joint lab, at the Institut d’Optique d’Aquitaine (Talence, France) / credit: Exail, G. Lemaintec
Schematic representation of the rotating atom interferometer: three orthogonal laser beams are used to trap and cool an ensemble of rubidium (87Rb) atoms in a retroreflected configuration. Mechanical accelerometers are attached to the back of the three mirrors and two fiber-optic gyroscopes (FOG) measure the rotations of the device along the x and y axes. The atom interferometer is performed on the z axis, where the reference mirror is mounted on a piezoelectric tip-tilt platform.

Exail presents the demonstration of an inertial sensor that leverages both classical and quantum technologies: a sensor that combines cold-atom technology with fiber-optic gyroscope technology, enabling high rotation rates and arbitrary orientations. This innovative hybrid sensor based on atom interferometry demonstrates its potential for inertial sensing in highly dynamic environments.

This achievement by the iXAtom joint laboratory, a research team shared with the LP2N lab1 in Bordeaux, marks a significant step towards the full capabilities of quantum inertial sensing for onboard applications (i.e. autonomous navigation or gravity mapping). The results are published in the journal Nature Communications.

Atom interferometers, also known as matter-wave interferometers, are inertial sensors that use the wave nature of atoms to measure extremely minute signals with exceptional precision. This technology has garnered significant interest for uses cases ranging from fundamental physics to geodesy and inertial navigation. However, their practical use for onboard applications is still limited. In the case of a moving carrier, the measurements of acceleration and rotation are intertwined and the extraction of one or the other is challenging.

Since 2017, the iXAtom joint laboratory, formed by Exail and LP2N lab experts, has focused on developing inertial sensors based on the hybridization of classical and quantum technologies2. Today, they present a novel approach: a hybrid rotating inertial sensor based on atom interferometry that maintains a full contrast and that accurately extracts the relevant inertial information.

The hybridization of the atom interferometer, which uses a cloud of Rubidium atoms that are trapped and cooled, with mechanical accelerometers and optical gyroscopes (Exail’s fiber-optic gyroscopes) along with an accurate model of the expected phase shift, allowed us to separate the acceleration and rotation contributions.” Baptiste Battelier, iXAtom/CNRS.

The research team has successfully demonstrated the operation of the hybrid sensor over a wide angle range (reaching 30°) and for high rotations rates (up to 14 ◦ s−1). This performance meets the operational requirements for various platforms, including undersea, sea, air and space applications. To achieve the long-term goal of a full quantum “strapdown” three-axis accelerometer, the rotation compensation system used in the experiment can be extended to a triad including three tip-tilt mirrors and three gyroscopes.

The complete validation of this strapdown strategy could lead to the development of a continuous hybrid quantum inertial measurement unit, with practical applications such as the improvement of gravity maps, geodesy as well as spaceborne applications. At Exail, as a leader in inertial navigation systems and in quantum technologies, we view these results as a significant milestone that demonstrates the benefits of our continuous investment in research within this promising field.” Vincent Ménoret, iXAtom/Exail

Laboratoire Photonique Numérique & Nanosciences – LP2N (CNRS / Institut d’Optique Graduate School / Université de Bordeaux)

2 In November 2022, the iXAtom joint lab had demonstrated the first hybrid three-axis accelerometer exploiting the quantum advantage (S. Templier and al. / Science Advances – 2022).

References:
Q. d’Armagnac de Castanet, and al, Atom interferometry at arbitrary orientations and rotation rates, Nature Communications, July 2024
DOI: https://doi.org/10.1038/s41467-024-50804-0