Influence of excited-state hyperfine structure on ground-state coherence -art. no. 012504

In a three-level Lambda system, a bichromatic light field can induce a grou nd-state coherence that leads to vanishing absorption of the bichromatic fi eld. Although this coherence is between ground states only, in a real atom it can nevertheless be influenced by the hyperfine structure of the excited state. We present experimental results which show that for suitable detuni ngs of the: bichromatic field from optical resonance, the specific contribu tion of each individual hyperfine level of the excited state can be disting uished through increased amplitude or width of the ground-state coherence.