Transferring a quantum state between a photon and a quantum memory is the key point for realizing a long-distance quantum communication, and is also a basic ingredient of linear optical quantum computation. In an atomic-based network, the efficient coupling between a photon and an atomic system is a prerequisite for realizing the transfer of information between them, which requires that the photon should have a comparable bandwidth with the natural bandwidth of an atom. Therefore, generating a narrow-band photon has become a very important topic in the quantum information field. One simple and efficient way is cavity-enhanced spontaneously parametric down-conversion. In this paper, we will review and introduce a series of experiments done in our group for realizing this goal. We believe these works are very useful for the research in this direction.
