  We report on the storage of light via the phenomenon of recoil-induced
resonance in a pure two- level system of cold cesium atoms. We use a strong
coupling beam and a weak probe beam to couple different external momentum
states of the cesium atom via two-photon Raman interaction which leads to the
storage of the optical information of the probe beam. We have also measured the
probe transmission spectrum, as well as the light storage spectrum which
reveals very narrow subnatural resonance features showing absorption and gain.
We have demonstrated that this memory presents the unique property of being
insensitive to the reading process, which does not destroy the stored
information leading to a memory lifetime limited only by the atomic thermal
motion.
