Nonlinear optical memory: theory and experiment

Abstract

The present work explores new possibilities for the selective storage of optical information through higher-order nonlinearities in a sample of cold cesium atoms obtained from a magneto-optical trap. Particularly, we demonstrate the storage of a third-, fifth-, and seventh-order nonlinear atom–light interaction into the coherences and populations of the Zeeman structure of the hyperfine cesium 6S1/2, F=3 ground state. Two writing beams create coherence and population gratings associated with high-order nonlinear processes, which can be selectively retrieved by a reading beam after a controllable storage time. Each kind of grating can store only specific orders of the nonlinear interaction, leading to special features in each signal. Applications of this nonlinear memory to herald multiphotons are discussed.