Our dual-axis accelerometer and gyroscope forms a building block of a six-axis inertial measurement unit. By recapturing the atoms after the interferometer sequence, we maintain a large atom number at high data-rates of 50 to 100 measurements per second. Two cold ensembles are formed in trap zones located a few centimeters apart, and are launched toward one-another. During their ballistic trajectory, they are interrogated with a stimulated Raman sequence, detected, and recaptured in the opposing trap zone. We achieve sensitivities at µg/√Hz and µrad/s/√Hz levels, making this a compelling prospect for expanding the use of atom interferometer inertial sensors beyond benign laboratory environments.
Image description: Front view diagram of the apparatus implementing the cold ensemble exchange and dual-axis, high data-rate atom interferometer. Two MOTs are loaded 36 mm apart. Cooling beams are shown in blue, probe beams in pink, and Raman beams in yellow. The trap is turned off, and the outer and inner cooling beams are blue and red detuned, respectively, which launches the ensembles towards each other. After the experiment, atoms are recaptured in the opposite trap to facilitate loading. The vector g shows the direction of gravity, while a is the direction of the acceleration sense axis. The rotation measurement axis points out of the page.
Video description: A slow motion movie demonstrating the launch and recapture technique. The ensembles are launched towards each other over 2 ms to a velocity of 2.5 m/s, with simultaneous sub-Doppler cooling. The interferometer takes place during their ballistic trajectory for ≈ 8 ms. Imaging beams are off during the interferometer to reduce photon scatter which would otherwise cause decoherence. Dashed circles represent the approximate positions of the ensembles during this stage. Atoms are then recaptured in the opposite trapping region, with additional atoms loaded from vapor for 7 ms. This process repeats here 50 times per second, but can be optimized to various rates to suit the application.