Large area atomic gyroscope

This new gyroscope experiment is based on a fountain configuration with 4 pulses to manipulate the atomic wave packets and which enables for a very large area of the interferometer. It relies on the use a single atomic sources launched along the vertical direction and which trajectory is bend by the gravity.

Picture of the new experimental setup, based on a fountain configuration with 4 pulses and giving access to one horizontal component of rotation with a very large sensitive interferometer area.

The atom wave-packets undergo a succession of four Raman pulses to manipulate the atomic wave-packets. The gravity bends the atomic trajectories such the two loops add there sensitivity to the Sagnac effect. The interferometer is then sensitive to one horizontal component of rotation with only one atomic source and without being sensitive to acceleration. This configuration enables to increase the measurement time, enlarging the interferometer area by more than two orders of magnitude to 11 cm². Specific experimental developments have been carried out to take full advantage of this very large area, including the development of flat intensity profile beams , Appl. Phys. Lett. 113, 161108 (2018), or the development of specific alignment procedures for Raman laser beams handling atomic wave packets , Phys. Rev. A 101, 033606 (2020).

Highly sensitive atomic gyroscope

This new setup gives the possibility to test the intrinsic limits of such interferometers. This is needed to use this kind of gyroscope for applications such as inertial navigation or geophysics. In particular, for the first time we have demonstrated the advantage in measuring continuously with an cold atom interferometer, which has already demonstrated record long term stability for a cold atom interferometer, at the 1 nrad.s^-.1 level , Phys. Rev. Lett. 116, 183003 (2016). We were then able to improve the operation of the gyroscope by developing interleaved measurements to effectively average out the rotational noise and make dynamic rotation measurements in a previously unexplored range. As a result, we demonstrate a stability of 0.3 nrad.s^-1, which rivals the best stability levels obtained with fiber-optic gyroscopes, and validates interleaving as a key concept for future atomic interferometry sensors probing time-varying signals, Science Advances, Vol. 4, no. 12, eaau7948 (2018).

Schematic of the principle of continuous cold-atom gyroscope. Continuous measurement is performed with a joint interrogation sequence where the atomic beam splitter is shared between the clouds entering and exiting the interrogation region.

Tailoring multi-loop atom interferometers with adjustable momentum transfer

We have demonstrated a new method of adjustable momentum transfer in multi-loop atomic interferometers, allowing suppression of spurious interferometry from the finite efficiency of atomic mirrors. By changing the wave vector of Raman splitters during interrogation,, the method allowed us to demonstrate a "pure" dual-loop gyroscope with strongly suppressed sensitivity to constant linear acceleration, which is of particular interest for applications where fluctuations in ground rotation velocity must be distinguished from linear translations, such as in rotational seismology, Phys. Rev. Lett. 125, 213201 (2020).

Accurate measurement of the Sagnac effect for matter waves with a dual axis gyroscope

The fundamental importance of the Sagnac effect has motivated experiments to test its validity for waves beyond the optical. We have performed a precise test of the Sagnac effect for matter waves, using an atom interferometer with two sensitive measurement axes. We measure the phase shift induced by the Earth’s rotation and find agreement with the theoretical prediction at a precision level of 25 parts per million, Science Advances, Vol. 8, no. 23, eabn8009 (2022).

Sagnac phase shift for both measuring axes of the cold atom gyroscope

Indeed, the expected performances should open the possibility of measuring fundamental parameters in geophysics, still inaccessible to the experiments, such as fluctuations of direction of the Earth’s rotation axis at intermediate time scale (few hours).

Publications

Romain Gautier, Mohamed Guessoum, Leonid A. Sidorenkov, Quentin Bouton, Arnaud Landragin, Remi Geiger
“ Accurate measurement of the Sagnac effect for matter waves ”
Science Advances, Vol. 8, no. 23, eabn8009 (2022)

 L. A. Sidorenkov, R. Gautier, M. Altorio, R. Geiger, A. Landragin
"Tailoring multi-loop atom interferometers with adjustable momentum transfer"
Phys. Rev. Lett. 125, 213201 (2020)

Copyright 2020 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.

Supplemental Material

 R. Geiger, A. Landragin, S. Merlet, F. Pereira Dos Santos
"High-accuracy inertial measurements with cold-atom sensors"
AVS Quantum Sci. 2, 024702 (2020).

 M. Altorio, L. A. Sidorenkov, R. Gautier, D. Savoie, A. Landragin and R. Geiger
"Accurate trajectory alignment in cold-atom interferometers with separated laser beams "
Phys. Rev. A 101, 033606 (2020).

Copyright 2020 by the American Physical Society

 D. Savoie, M. Altorio, B. Fang, L. A. Sidorenkov, R. Geiger, A. Landragin
“ Interleaved Atom Interferometry for High Sensitivity Inertial Measurements ”
Science Advances, Vol. 4, no. 12, eaau7948 (2018)

 N. Mielec, M. Altorio, R. Sapam, D. Horville, D. Holleville, L.A. Sidorenkov, A. Landragin, R. Geiger
“Atom Interferometry with Top-Hat Laser Beams ”
Appl. Phys. Lett. 113, 161108 (2018), arXiv:1808.03355

Copyright 2018 American Institute of Physics.This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.

 B. Fang, N. Mielec, D. Savoie, M. Altorio, A. Landragin and R. Geiger
"Improving the phase response of an atom interferometer by means of temporal pulse shaping"
New J. Phys. 20, 023020 (2018)

 I. Dutta, D. Savoie, B. Fang, B. Venon, C. L. Garrido Alzar, R. Geiger, and A. Landragin
“Continuous Cold-Atom Inertial Sensor with 1  nrad/sec Rotation Stability”
Phys. Rev. Lett. 116, 183003 (2016)

Copyright 2016 by the American Physical Society

 B. Fang, I. Dutta, P. Gillot, D. Savoie, J. Lautier, B. Cheng, C. L Garrido Alzar, R. Geiger, S. Merlet, F. Pereira Dos Santos, A. Landragin
“Metrology with Atom Interferometry: Inertial Sensors from Laboratory to Field Applications”
Proceedings of the 7th Symposium on Frequency Standards and Metrology, Postdam (Germany), 12-16 Oct. 2015,
Journal of Physics: Conference Series 723 (2016) 012049.

 M. Meunier, I. Dutta, R. Geiger, C. Guerlin, C. L. Garrido Alzar, and A. Landragin
"Stability enhancement by joint phase measurements in a single cold atomic fountain"
Phys. Rev. A 90, 063633 (2014)

Copyright 2014 by the American Physical Society