Light-pulse atom interferometers (LALIs) are useful as inertial sensors, measuring acceleration and rotation. In addition to being extremely sensitive, LAIs show a highly accurate scale factor and stable baseline even without calibration, unlike classical sensors such as laser gyroscopes. Rotation sensing however, does not yet benefit fully from this stability. In existing sensors, one of these dimensions for the enclosed area A is determined by the atoms’ initial velocity, a quantity known to relatively low precision. Moreover, all LAIs, including “compact” versions for inertial navigation, use beam splitters based on Raman transitions (which limit their sensitivity and introduces systematic effects), atomic fountains (which are ~1-m tall and must be carefully aligned with respect to the vertical), and free-beam optics (which limit available laser intensity and wavefront purity).
To address these challenges, investigators at University of California at Berkeley have developed a cavity-based atom interferometer which overcomes these limitations. This atom interferometer is provided a 40 cm optical cavity to enhance the available laser power, minimize wavefront distortions, and control other systematic effects symptomatic to atomic fountains. This innovated system allows the production of LAI inertial sensors that simultaneously measures linear accelerations and rotations. The cavity-based interferometer offers the full performance of a large-scale atomic fountain within a small volume. The cavity-based interferometer will surpass the baseline stability of current rotation sensors. It will allow spatial separations between atomic trajectories comparable to larger scale fountains within a more compact device.