Atomic coherence and interference in a coupled atom-cavity system

摘要

When a coherently prepared atomic medium is confined in an optical cavity, the atomic coherence and interference manifested by electromagnetically induced transparency (EIT) can be manipulated and enhanced by the collective atom-cavity coupling and the cavity feedback. We present an experimental study of the light transmission through an optical cavity coupled with coherently prepared cold Rb atoms. In the frequency domain, the cavity transmission spectrum exhibits spectral peaks representing the cavity normal modes associated with the multi-atom vacuum Rabi splitting and the intra-cavity dark state manifested by the combined EIT effects of the absorption suppression and the steep normal dispersion. In the time domain, a light pulse coupled into the cavity mode propagates with a slow group velocity and the propagation time delay is significantly increased by the cavity feedback.