A New Starting Point for Atom Interferometry

Interferometers using atoms rather than light can measure acceleration and rotation to high precision. Because atoms are slower than light, atom interferometers have the potential to reach greater inertial sensitivity than their optical counterparts. However, one of the main limitations in atomic interferometry has been discriminating the different contributions to the interference signal. Bright/dark fringes at the output of an atom interferometer result from phase shifts induced by multiple inertial effects as well as interferometer imperfections. In Physical Review Letters, Susannah Dickerson and colleagues from Stanford University, California, now report on a new method that can directly resolve and characterize these phase shifts. They perform their “point source interferometry” on a 10-meter-high atomic fountain, where they can simultaneously measure rotation and acceleration with unprecedented sensitivity [1]. The results open new perspectives in the development of ultraprecise inertial navigation systems as well as future precision tests of general relativity.