Theory of the light - atomic ensemble interface

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

A program of theoretical research on the interaction of light with cold, optically thick, atomic ensembles is proposed. Quantum control of the interface between light fields and atomic matter is essential for future scalable quantum network systems which have application to the secure sharing of information between remote parties. The success of the implementation of atomic ensembles in that context depends on achieving high efficiency and long-lived coherence in their interaction with the light input and output channels. The properties and characteristics of the interactions in such a multi-mode and multi-atom system will be thoroughly addressed by means of the analytical and numerical methods of atomic physics and quantum optics. The collective enhancement of the interactions between the light field and multi-atom states of the ensemble provides an organizing principle for their understanding, as well as a mechanism for strong, directional coupling between light and matter. Another characteristic of light propagation in optically thick media, the mixed light/multi-atom excitation known as the dark state polariton, will be investigated as a means to perform controlled storage, and subsequent retrieval, of light pulses down to the single photon level. The research will focus on realistic experimental scenarios including the study of relevant states of preparation of the atomic ensemble, and the incident light fields. In this context, the coupling of ambient magnetic fields to the spins of the atomic nucleus and electrons provides the primary decoherence mechanism. This process and its impact on the overall storage and retrieval efficiency of the light field will be investigated in detail.