Production of Atomic Alkali-Metal Beams in Single Hyperfine Sublevels

A compact source which produces atomic alkali-metal beams in individual hyperfine sublevels has been developed. The methods are demonstrated with ${}_{}{}^{23}{}_{}{}^{}\mathrm{Na}$ atoms. Initially nearly all atoms are transferred into one hyperfine sublevel ($|F, m_F〉=|2, 2〉$) by a double-resonance technique using laser optical pumping and rf transitions. Subsequently the other hyperfine sublevels can be populated selectively by an adiabatic high-frequency transition. The hyperfine sublevel populations are determined by laser-induced fluorescence spectroscopy in a magnetic field.