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 ²³Na atoms. Initially nearly all atoms are transferred into one hyperfine sublevel (|F, mF〉=|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.