Light Qubit Storage and Retrieval using Macroscopic Atomic Ensembles
  We present an experimentally feasible protocol for the complete   storage and retrieval of arbitrary light states in an atomic quantum   memory using the well-established Faraday interaction between light   and matter. Our protocol relies on multiple passages of a single   light pulse through the atomic ensemble without the impractical   requirement of kilometer long delay lines between the passages.   Furthermore, we introduce a time dependent interaction strength   which enables storage and retrieval of states with arbitrary pulse   shapes. The fidelity approaches unity exponentially without squeezed   or entangled initial states, as illustrated by explicit calculations   for a photonic qubit. 
J. Sherson, A. S. Soerensen, J. Fiurasek, K. Moelmer, and E. Polzik