Upgrades for the optical lattice atom interferometer

Atom interferometers are powerful tools for probing fundamental physics

and inertial sensing applications. However, their performance has been

limited by the available interrogation time of atoms freely falling in

Earth's gravitational field. Recently, we demonstrated a trapped atom

interferometer with visible interference fringes after 25 seconds of

interrogation time. The spatially separated wave packets are held by the

resonant mode of an optical cavity, rather than dropped in free fall.

After seconds of hold time, the gravitational potential energy

differences from micrometers of vertical separation can generate

megaradians of interferometer phase. In addition, this trapped geometry

can strongly suppress the phase variance caused by vibrations, thus

addressing the dominant noise source in atom-interferometric

gravimeters. We describe recent progress on improving long-term

stability, imaging, trap depth and other interferometer capabilities.