| Scope and method of study. The purpose of this research was to use laser cooling techniques to cool a sample of rubidium 87 atoms and pulse the cold atoms with an off-resonant standing wave of light. Among the objectives of the study was to understand the parameters needed to place the cold atoms in a quantum accelerator mode and to compare with experiments performed with cesium 133 atoms. A vacuum system and optical system were designed and built to produce a sample of laser cooled rubidium 87 atoms.; Findings and conclusions. With the proper parameters, such as initial velocity of the atoms, time between each pulse, and gravitational potential, a linear gain in momentum of the atoms with each pulse was observed. This defined a quantum accelerator mode. Experiments performed by changing the parameters of initial atom velocity and time between each pulse are compared to those of previous experiments with cesium 133. A major difference in the two species, rubidium 87 and cesium 133, was the effect of the pulsing light's polarization. The pulsing light's polarization had little effect on the efficiency of the rubidium quantum accelerator mode. Whereas, cesium 133 requires linear polarization of the pulsed light. Higher order accelerator modes were observed and matched with theory. |
