CONCENTRATION OF ATOMIC POPULATION IN ANY SINGLE-GROUND-STATE MAGNETIC SUBLEVEL IN ALKALI-METAL VAPORS

A scheme for concentrating a large fraction (approximately 100%) of the alkali-metal atoms in an atomic vapor in any single magnetic sublevel of the ground state is developed. This is experimentally demonstrated in the Rb-87 vapor. The atomic vapor is optically pumped to a high degree of spin polarization after which two radio-frequency pi pulses are applied to transfer the atomic population from the (2,2) or (2, -2) (F, M(F)) state to the (2,0) sublevel of the ground state. The resulting distribution is diagnosed using a microwave field tuned to the hyperfine transition (6834 MHz).