A 200-Hz Data Rate Sub-Doppler-Cooled Grating Magneto-Optical Trap towards Compact Time-Multiplexed Multi-Axis Inertial Sensing

Quantum gravity and inertial sensors have been demonstrated (as gravimeters, gravity gradiometers, accelerometers, and gyroscopes) in the laboratory with exquisite sensitivity based on light-pulse atom interferometer (LPAI) technology, which continue to be developed for various mobile platforms in real-world applications. A long-baseline low data rate LPAI leads to high sensitivity scaling quadratically with the interrogation time, T, between LPAI light pulses. However, such a low data rate LPAI is more vulnerable to vibration and high dynamics. High data rate LPAI operation in a small form-factor is less sensitive to real-world environments because a short T can reduce the relative movement between the atomic cloud and the light pulses. A grating magneto-optical trap (GMOT), based on a single laser-cooling beam rather than six beams, helps reduce the complexity of the LPAI laser delivery system and the size of the sensor head. Here we report the progress in the continued development of (1) a compact 1-axis GMOT LPAI sensor head that uses a 200-Hz data rate sub-Doppler-cooled GMOT and (2) time-multiplexed multi-axis acceleration sensing approach with multi-axis GMOT LPAI sensor concept. Here we characterize high data rate sub-Doppler-cooled GMOT operation with atom recapture (via multiple parameters of cooling-beam intensity/detuning, atom number, and atom temperature) and study achievable LPAI sensitivity using this platform. Our on-ongoing efforts will accelerate the demonstration of a quantum inertial measurement unit (including a 3-axis quantum accelerometer and a 3-axis quantum gyroscope) in a simple and compact package.