Vertical Contrast Interferometry and Bloch-Band Approach to Atom Optics

Thesis (Ph.D.)--University of Washington, 2020This dissertation covers a series of atom interferometry experiments with a focus on applying the Bloch-band model to atom optics and performing vertical interferometry with a magnetically neutral atom. This approach lets us analyze the diffraction processes from a pulsed optical lattice in terms of the Bloch solutions for the atom in the periodic lattice Hamiltonian. Using a ytterbium (174Yb) Bose-Einstein condesate as the matter-wave source, measurements of Rabi frequencies, as well as those of diffraction phase and amplitude, demonstrate the validity of the Bloch-band approach over a regime which is typically satisfied within an atom interferometer. Applications for this model are discussed, including the use of an interferometric phase measurement to determine an unknown band structure. Additionally, a unique feature of the excited Bloch-bands—the magic depth—is exploited to improve the phase stability of atom interferometers which use Bloch oscillations for large momentum transfer. We also demonstrate the technique of delta-kick cooling as a fruitful method for reduction of the BEC’s vertical velocity distribution, allowing for more efficient momentum transfer with a vertical optical lattice. This is a crucial tool for non-magnetic atoms such as 174Yb, which we use to perform vertical interferometry in our system with both a contrast interferometer geometry and a double Mach-Zehnder interferometer. Lastly, the effect of Landau-Zener-St¨uckelberg interference during Bloch oscillations is studied in its relation to momentum transfer efficiency for precision interferometry