Optical measurement of 3He nuclear polarization for metastable exchange optical pumping studies at high magnetic field
M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Krakow, Poland
2 Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Krakow, Poland
3 Department of Physics, Agricultural University, Al. Mickiewicza 21, 31-120 Krakow, Poland
4 Faculté des Sciences, Université Saint Joseph, BP. 11-514 Riad el Solh, 1107 2050 Beirut, Lebanon
5 Laboratoire Kastler Brossel, école Normale Supérieure, 24 rue Lhomond, 75005 Paris, France
An accurate optical method to measure the nuclear polarization of 3He atoms in the 11S ground state is described. The absorption of a weak, probe laser beam is used to measure the relative populations of two hyperfine sublevels of the 23S metastable state that are not addressed by the pumping laser beam. Since a common spin temperature between the ground and metastable states is established by metastable exchange collisions, the nuclear polarization can be derived from these absorption measurements. The method is highly sensitive, robust, and can be used to monitor the dynamics of optical pumping and relaxation processes without interfering with them. It was successfully implemented and tested in the 0.45–2.0 T magnetic field range at the 3He gas pressure up to 67 mbar.
© EDP Sciences, Springer-Verlag, 2007