Experiments with optically and magnetically trapped cesium atoms

Optical traps have recently become an efficient source of relatively dense (10{dollar}sp{lcub}11{rcub}{dollar} atoms/cm{dollar}sp3){dollar} and very cold (10{dollar}sp{lcub}-6{rcub}{dollar} Kelvin) atoms. In this extreme temperature regime, optically trapped and cooled atoms are ideal for ultra-high resolution spectroscopic studies and detailed measurements of interatomic interactions. I present a dramatic simplification to the production of optically trapped atoms by loading cesium atoms into an optical trap directly from a background vapor in a closed low-pressure vapor cell. Cesium atoms accumulate to a region inside the cell where several beams from two frequency-stabilized diode lasers intersect. Up to 10{dollar}sp8{dollar} atoms are trapped to a density of 3 {dollar}times{dollar} 10{dollar}sp{lcub}10{rcub}{dollar} atoms/cm{dollar}sp3,{dollar} and can be cooled to under 5 {dollar}mu{dollar}K. As an example of the uses of trapped and cooled atoms, spectroscopy of the cesium "clock" transition is performed on optically trapped and cooled cesium atoms, yielding excellent fractional frequency resolution.; The low temperature and high density limits of optically trapped atoms seem to be governed by the necessary presence of resonant photons among the atoms in the trap. With the goal of attaining even higher densities ad lower temperatures, I have turned to loading optical trapped atoms into a purely magnetic trap, where no photons are required for confinement. The cesium atoms are confined to a local three dimensional minimum in the magnetic field magnitude, produced with a configuration of DC coils. Alternatively, the atoms are confined in an AC magnetic trap, a new type of magnetic trap we developed similar to the Paul electrodynamic trap for electric charges. It is hoped to cool and compress the magnetically trapped atoms via evaporation, already a proven technology in magnetically trapped hydrogen. However, continuous evaporation depends on rethermalizing elastic collisions between trapped atoms. I present a new measurement of these very low energy elastic collisions in a magnetic trap, and consider the requirements for cooling and compression past the Bose-Einstein condensation transition point in a trapped vapor of cesium.