91ÅÝܽ

Synopsis

Precise and accurate measurements of local gravity are a key tool in diverse fields such as oil, gas, and mineral exploration, civil engineering, hydrology, and inertial navigation. Absolute quantum gravimeters are particularly attractive for these applications due to their high precision and accuracy, but they also have high size, weight, and power (SWaP) which severely restricts their use. In this talk, I will present research done by the Quantum Sensors Group at the Australian National University aimed at reducing the SWaP of absolute gravimeters. In part one, I will discuss absolute gravimeters based on atom interferometry, highlighting our recent work on using open interferometry and spatial fringes to reduce the readout delay associated with Bragg transitions while simultaneously avoiding the problem of phase inference. In part two, I will argue that all gravimeters based on interferometric tracking of free-falling test masses are quantum gravimeters, and I will then present our recent revisiting of optical gravimeters based on free-falling retroreflectors, highlighting the key advantages and disadvantages of optical versus atomic gravimeters.