Efficient Images Storage Due to a Microwave Field in a Cold Four-Level Atomic System

Abstract

Quantum memories that are able to store arbitrary two-dimensional images offer advantages over light pulses memories, in terms of both speed and capacity. In this work, we propose an efficient scheme to realize the storage and retrieval of images in a four-level quasi-Λ system of cold atoms. This scheme relies on the cross-phase modulation controlled by an employed intensity dependent microwave field during the storage time. Both theoretical analysis and numerical simulation clearly show that the microwave field can effectively modify the spin coherence and improve the visibility of the reconstructed images with low nonlinear absorption. The phase shift and energy retrieving rate of the probe field are immune to the coupling field and the atomic optical density. Compared to the existing scheme, the maximum advantage of this one is that the energy loss in this process is reduced markedly. This work provides an alternative way for efficiently enhancing the performance of EIT based light-storage devices for all-optical quantum information processing.