Manipulating Alkali-Atom Bose-Einstein Condensates and Atom Lasers with Laser Light

Mark Edwards

Department of Physics

Georgia Southern University

One of the most exciting applications of the recently observed alkali-atom Bose-Einstein condensates (BEC) is their use as a coherent source of matter waves, i.e., an atom laser. Applications of atom lasers include atom holography, time and frequency standards, and nanolithography. A crucial design element in a practical atom-laser device is the mechanism whereby atoms are coherently removed from the condensate called an output coupler (OC). One such OC design uses counterpropagating laser beams to remove condensate atoms via a two-photon Raman transition; a so-called Raman OC. Recently, in a beautiful series of experiments performed at the National Institute of Standards and Technology (NIST), condensate atoms were outcoupled by this process. Furthermore, this output coupling technique was used to measure the coherence length of an atom laser containing this OC design element. I and my collaborators have successfully modeled these data and have used the model to produce a simple picture of the output coupling process. In this talk I will present a brief review of the physics of alkali-atom BECs. Furthermore I will describe the NIST coherence-length experiments and how the results can be understood in terms of the changing momentum distribution of an expanding condensate. I will conclude with a brief description of the impact of this understanding on future atom-laser design.