Quantum beats in forward scattering: subnanosecond studies with a mode-locked dye laser

Abstract

Time-resolved polarization spectroscopy of transient coherent superpositions of atomic substates is extended to the picosecond time scale by using a synchronously pumped mode-locked dye laser. As a first demonstration, hyperfine beats in the sodium D₁ and D₂ lines were resolved. The ground-state splitting could be determined with an accuracy of better than 10⁻³.