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

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 from the velocity-dependent Sagnac phase shift and 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. We show that by introducing a pseudorotation effect with appropriate two-photon detunings for Raman light 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 apply this method to an interferometer gyroscope with counterpropagating atomic beams sharing the same Raman light. 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 an interferometer gyroscope with thermal atomic beams of rubidium-87, achieving a measurement of angular velocity of $1.0{\phantom{\rule{0.2em}{0ex}}}^{\ensuremath{\circ}}/\mathrm{s}$ even with an acceleration of $0.68\phantom{\rule{0.2em}{0ex}}\mathrm{m}/{\mathrm{s}}^{2}$ on a three-axis rotation table. This simple and robust dispersion-compensation method with Raman-light detuning will benefit dynamic angular velocity measurements in field applications such as the inertial navigation of vehicles.