Jeremy Glick, UT-Austin

"An intense cold atom source and 7Li4He formation using a seeded supersonic jet"

Abstract: Continuous, high-intensity, cold atomic beams are important for precision measurement and atom optics applications. Laser cooling and buffer gas-based methods are already well-developed, but new methods that could potentially provide brighter beams are still of interest. In this talk, I present our group's work on a new approach based on continuous post-nozzle injection of lithium atoms into a supersonic helium jet. We reduce the jet velocity to 210 m/s by cryogenically cooling the helium nozzle and extract the lithium atoms with magnetic focusing. The focused beam has a brightness comparable to laser-cooled sources, with a longitudinal temperature of 7(3) mK.

Using this source, we have observed the formation of 7Li4He dimers in the jet. These are formed by three-body collisions and are detected with laser-induced fluorescence. In contrast to previous work using buffer gases, the dimers are two orders of magnitude colder, with a temperature of 10 mK. As such, this method opens up the possibility to explore dimer formation of various weakly bound van der Waals molecules which have yet to be observed experimentally. I will also discuss efforts to measure the binding energy of 7Li4He using photoassociation spectroscopy as well as analysis of the formation rate of the dimers in the helium jet.