Progress on Building an Airborne Atomic Gravity Gradiometer

We previously reported a compact cold atom gravimeter that achieved a sensitivity of 37 Gal/Hz and a long term stability of 2 Gal. Now we describe recent progress in the construction of our drone-based atomic gravity gradiometer for airborne autonomous gravity surveys. Our device will measure the vertical gravity gradient with a target sensitivity of 10 Eotvos/(Hz) while mounted on an unmanned quad-rotor aircraft capable of 30 minute to 1 hour flight times. The total mass of the aircraft and sensor payload will be 100-150 Kg. The gradient is measured by two vertically displaced, simultaneous Mach-Zehnder interferometers probed with the same lasers. Major upgrades since our previous gravimeter include using diffractive optics for generating the cooling and trapping laser beams, and using a state-of-the-art flat-top beam shaper for interferometry pulses.