Coherence effects in laser-rf double resonance.

Abstract

An ``amplitude model'' of the laser-rf double-resonance process has been quantitatively verified, providing a complete explanation of the anomalous line shapes observed in studies of ${\mathrm{Na}}_{2}$ hyperfine structure. We find excellent agreement with new laser-rf double-resonance measurements in low-J'' rotational levels of the ${X}^{1}$${\ensuremath{\Sigma}}_{g}^{+}$(v''=0) ground state of ${\mathrm{Na}}_{2}$ as well as with earlier data for J''=28. These results confirm the idea that absorption and stimulated-emission Rabi cycles in the presence of the laser field create coherence between the ground-state hyperfine levels when these levels are optically unresolved. A novel ground-state ``quantum beat'' experiment is proposed.