The frequency dependence of the collisional trap loss rate for ultracold sodium atoms held in a magneto-optical trap was measured using the optical catalysis technique. The experiment was carried out near the 3S
Collisions between ultra-cold (T << 1K) atoms confined in a magneto- optical trap (MOT) may result in the ejection of atoms from the trap. These collisional loss processes, which involve ground state/excited state collisions, fundamentally limit the density attainable in MOT traps. Although accurate calculations of collision rates between ultra-cold atoms require precise knowledge of the molecular potentials over a long range, the loss rate for Li was recently predicted to be significantly less than for the other alkali metals. Motivated by this result, we are measuring the collisional loss rate of Li in a vapor-cell MOT using a red-detuned laser beam to catalyze the collisions, similar to recent experiments using Rb and Cs. We will report our progress to measure the trap loss rate for {sup 6}Li and {sup 7}Li, which will be compared to investigate an isotopic dependence, as was recently observed for Rb.
Summary form only given. All the experiments and theories describing atomic traps and cold collisions have considered only homonuclear systems. Cold collisions involving different atomic species open up new and exciting possibilities, including high-resolution studies of heteronuclear molecular band formation. We have carried out an experiment on the simultaneous magneto-optical trapping of two alkali atoms: Na and K. Collisional rate constant of trap loss resulting from cross atomic collisions was investigated through the transient loading of the trap.
We investigate the loading of a two-color vapor-cell magneto-optical trap for sodium atoms as a function of several operational parameters of the trap. We use two laser frequencies acting in different spatial regions to obtain either enhancement or inhibition of the capture mechanism. We demonstrate that the best enhancement is achieved when the trap operates on a combination of atomic transitions, known as type I tuning, by using a second laser beam to capture atoms through a different combination of transitions (type II tuning).