Atom Interferometry in an Optical Cavity and Applications

Light pulse atom interferometers use pulses of light to coherently split matter waves and utilize interference to measure the relative phase between paths. Measurement sensitivity increases with the enclosed space-time area. Several techniques have been developed to increase momentum transfer including high order Bragg diffraction. This has been limited to 24 $\hbar k$ in a single pulse by laser power and beam quality such as wavefront distortions. We are developing an interferometer in a vertically-mounted 40 cm long Fabry-Perot cavity using cold Cs atoms. The cavity enhances available laser power, controls optical wavefronts, and is expected to provide $>100~\hbar k$ momentum transfer in a single Bragg diffraction process. Such a demonstration would provide a competitive gravimeter in a compact device. In addition, the optical cavity reduces uncertainties in beam alignment and divergence. This feature allows light pulses to enclose a well-defined spatial area for a Sagnac gyroscope with high scale factor stability. Finally, the compact design and large momentum transfer expected allow for the introduction of two source masses for a possible demonstration of the gravitostatic Aharonov-Bohm effect. We report on our experimental progress and discuss these applications.