Development of Compact, Deployable Sensors Using Cold Atom Interference
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Abstract
This dissertation makes three distinct contributions to the field of compact cold atom interferometry. First, a two-dimensional grating magneto-optical trap (2D GMOT) is demonstrated, in which a single laser and a planar diffraction grating produce a slow, high flux beam of 87Rb atoms. This configuration increases experimental access when compared with a traditional 2D MOT. The output flux is several hundred million rubidium atoms/s at a mean velocity of 19.0(2) m/s. The velocity distribution has a 3.3(17) m/s standard deviation. The atomic beam from the 2D GMOT is used to demonstrate loading of a three-dimensional grating MOT (3D GMOT) with 2.02(3) x108 atoms. Methods to improve flux output are discussed. Second, a method to produce uniform magnetic fields of arbitrary direction from a single planar microchip is developed. Chip-based fields reduce the dependence of cold atom devices on large current-carrying coils external to the vacuum chamber. A chip is fabricated that demonstrates equivalent magnetic field uniformity to the widely-used Helmholtz coil pair. These results are used to propose a novel magnetic trap conveyor to move atoms along the surface of the chip without the use of an externally-supplied field. Third, using a thermal gas, the signal of a trapped atom interferometer is modeled. This interferometer uses two short laser pulses, separated by time T, which act as phase gratings for the matter waves. Near time 2T, there is an echo in the clouds density due to the Talbot-Lau effect. The model uses the Wigner function approach and includes a weak residual harmonic trap. The analysis shows that the residual potential limits the interferometers visibility, shifts the echo time, and alters its time dependence. Loss of visibility can be mitigated by optimizing the initial trap frequency just before the interferometer cycle begins.