Closed-loop measurements in an atom interferometer gyroscope with velocity-dependent phase-dispersion compensation

TL;DR

This paper introduces a velocity-dependent phase-dispersion compensation method in atom interferometer gyroscopes, enabling accurate large angular velocity measurements despite atomic velocity spread, with potential for field inertial navigation.

Contribution

The study presents a novel technique using Raman light detuning to cancel Sagnac phase shifts, improving the dynamic range and robustness of atom interferometer gyroscopes.

Findings

Successfully measured 1.0°/s angular velocity with rubidium-87 beams.

Achieved compensation of velocity-dependent phase dispersion.

Demonstrated robustness against atomic beam velocity variations.

Abstract

Atom interferometer-based gyroscopes are expected to have a wide range of applications due to their high sensitivity. However, their dynamic range is limited by dephasing caused by velocity-dependent Sagnac phase shift in combination with the longitudinal velocity distribution of the atoms, restricting measurements of large angular velocities. In this study, we present a method for restoring the contrast deterioration in angular velocity measurements with interferometer gyroscopes using atomic beams. Our findings show that by introducing the pseudo-rotation effect with appropriate two-photon detunings for Raman lights in the interferometer, it is possible to effectively cancel the Sagnac phase shift for all atoms in the velocity distribution of the beam. Consequently, the contrast is unaffected by the rotation. Furthermore, we applied this method to an interferometer gyroscope with counter-propagating atomic beams sharing the same Raman lights. It is found that the angular velocity of the system can be estimated through the detuning point where the phase difference between the two interferometers is zero. This approach ensures that the scale factor of the atom interferometer gyroscope is independent of the change in the longitudinal velocity distribution of the atomic beam. We demonstrate our technique using the interferometer gyroscope of thermal atomic beams of rubidium-87, achieving a measurement of angular velocity of $\mathrm{{1.0}^{\circ}/s}$ even with an acceleration of 0.68$\mathrm{m/s^2}$ on a three-axis rotation table. This simple and robust dispersion compensation method with Raman light detuning benefits dynamic angular velocity measurements in field applications such as the inertial navigation of vehicles.