The Department of Physics and Astronomy invites you to a colloquium featuring Dr. Brian Saam, Department of Physics and Astronomy, University of Utah. Dr. Saam will present his talk, “Hyperfine Physics in Alkali-Metal Vapors”, Thursday, March 31 at 4:10 p.m. in Webster B17.
Meet for refreshments before the lecture at 3:45 – 4:10 p.m. in the foyer on floor G above the lecture hall.
Abstract:
Although alkali-metals were all discovered by the mid-19th century, vapors of these Column I elements have been studied with particular intensity in the last 75 years, initially as pseudo-one-electron systems with easily accessed optical or near-infrared P→S transitions to the ground state having strong oscillator strengths. Currently, they are widely used in precision magnetometry, atomic clocks, and in gyroscopes; they are also of fundamental importance in the study of cold atoms, Bose-Einstein condensates, and atom interferometry—even some table-top searches for physics beyond the standard model. All stable alkali-metal isotopes have half-integer nuclear spin, and the ground-state hyperfine coupling to the valence electron generates a rich spin physics that is crucial to all of these areas of study. Our laboratory focuses on optical pumping: the use of circularly polarized resonance light to produce large non-equilibrium ground-state spin polarization in alkali-metal vapors. We also work on the technique of spin-exchange transfer of this polarization to the nuclei of certain noble gases (3He and 129Xe), which also finds a host of both fundamental and practical applications, including magnetic resonance imaging of the lung. We have worked most recently on characterizing magnetic-resonance frequency shifts in hyperfine transitions that result from interactions between the polarized alkali-metal vapor and the polarized noble-gas nuclei. These are studied optically with much higher sensitivity than inductive techniques; indeed, such shifts can be used as a sensitive probe of the noble-gas magnetization. These specific results and a brief overview of other areas of interest in our laboratory will be presented.
