Digital closed-loop thermal atomic-beam interferometer for high-bandwidth, wide-dynamic-range, and simultaneous absolute acceleration–rotation sensing

Since atom interferometers are sensitive to both acceleration and rotation, inertial navigation systems can be simplified compared with conventional multi-sensor configurations. However, accurate navigation requires distinguishing between them in the interferometer output. While such measurements have been demonstrated using atomic-fountain sensors [1], high-bandwidth, simultaneous, and continuous absolute measurements with thermal atomic beams—better suited for practical inertial navigation—have not been reported. We propose a digital closed-loop atom interferometer using a thermal atomic beam, inspired by fiber-optic gyroscopes. The scheme synchronizes phase biasing with momentum-kick reversal through the atomic transit time and extracts four interferometric phases to suppress Raman beam path-length errors. Closed-loop feedback maintains a pseudo-inertial frame via two-photon detuning control, eliminating cross-coupling between acceleration and rotation. Simulations with a rubidium beam from a 170°C effusive oven and a 100 mm arm predict a velocity random walk of 3 μm s^-2 Hz^-1/2 and an angular random walk of 15 μdeg Hz^-1/2, surpassing state-of-the-art sensors. Experimental progress on the digital closed-loop scheme will be presented on the poster.

[1] B. Canuel et al., Phys. Rev. Lett. 97,010402 (2006).