| This dissertation describes the development and characterization of a Holographic Atom Trap. This trap, or HAT, employs a novel configuration of far-off resonant laser beams to create a periodic array of small potential wells. These wells, or microtraps, typically measure 10 μm x 10 μm x 100 μm in the HAT implementation described here, and confine up to 18,000 atoms each at temperatures near 50 microkelvin. The very high oscillation frequencies within the microtraps (ν = 18.4 kHz) lead to high atomic densities (>1014 CM−3) and a phase space density greater than 1/260.; We also present a new type of imaging system useful for traps such as the HAT, known as Spatial Heterodyne Imaging, which we have developed and characterized. This technique measures the index of refraction of a cloud of atoms over a wide range of spatial sizes and without the need for specially-fabricated optics. Spatial Heterodyne imaging is a non-destructive technique, and we demonstrate images with a signal-to-noise ratio greater than ten made with fewer than 0.0004 photons scattered per atom.; Our studies of laser cooling in the HAT are discussed at length. We show that the 50 μK temperature is determined by free evaporation within the trap, and that laser cooling has no effect on the temperature of atoms in our trap. Instead we find that the temperature is determined by the depth of the potential trap. An excited-state mixing process is proposed to explain the inability of laser cooling to break the 50 μK barrier.; We have performed a number of forced evaporation experiments with our HAT. By decreasing the potential trap depth we eject hotter atoms from the trap and effectively cool those that remain. We present data with a variety of shapes for the decreasing potential ramp, including an optimized ramp which cooled 1,100 atoms to ∼100 nK which corresponds to a phase space density of 0.91+1.1−0.5. Finally, we discuss the factors that limit the ultimate phase space density and our efforts to overcome them. |
