Reversible storage of a weak light pulse optimized by spontaneously generated coherence

We investigate the storage and retrieval of a weak light pulse in a Λ-type three-level atomic gas medium with spontaneously generated coherence and pumped by an incoherent field. The scheme works based on electromagnetically induced transparency and can promote retrieval efficiency. We show how to make the combination choice of the system parameters required not only for the perfect retrieval operation but also for the high atom-field coupling efficiency.