Electromagetically induced transparency with nuclear spin.

We report the observation of electromagnetically induced transparency in a sample of cryogenically cooled ground-state atomic ytterbium ((1)S(0)). The transparency is produced due to coherence between the optical field and the nuclear spin state of the (173)Yb nucleus. Because the nuclear spin states interact very weakly with their environment, they are resistant to decoherence due to inelastic collisions and inhomogenous fields. Consequently, atomic ensembles of pure nuclear spin states may be a superior medium for a variety of nonlinear optics and quantum information experiments.