UNC-CH Physics and Astronomy Colloquium

Thad Walker, University of Wisconsin–Madison

“Turning Photons into Polarized Nuclei”

Spin-exchange optical pumping (SEOP) uses collisions between optically active and optically inactive species to convert the angular momentum of light into spin angular momentum. I will present a particularly important form of SEOP in which large quantities of noble gas spins, usually He or Xe, can be spin-polarized to nearly 100%. SEOP of noble gases originated with nuclear magnetic resonance gyros in the 1970s, then with the advent of high power tunable lasers became useful for targets for nuclear and particle physics in the 1990s, followed shortly by use in novel forms of magnetic resonance imaging. I with conclude with a few recent examples of precision measurements that use SEOP.