Spin-exchange optical pumping of mixtures of alkali-metal vapors and n
oble gases can be used to efficiently polarize the nuclei of the noble
-gas atoms. Liters of noble gases at standard temperature and pressure
and with nuclear spin polarizations of several tens of percent are no
w used in many applications. The authors describe the basic phenomena
that govern the spin-exchange process and review the physics of angula
r momentum transfer and loss in optical pumping and spin-exchange coll
isions.