Quantum Memory of Photonic Image and Its’ Superposition

Abstract

As a critical component device in quantum communications, quantum memory would enable the distribution of quantum information in long-distance node [6]. Single photons are the most perfect candidate of quantum information carriers, thus playing an essential role in quantum information science. Encoding photons with spatial shape through high-dimensional states significantly increases the information carrying capability and network efficiency, because high-dimensional state can implement many protocols, such as high-dimensional quantum communication, that two-dimension cannot [19]. In this chapter, I describe how we demonstrate storing photons carrying images in spatial and frequency multiplexing, and explore the effects in these memory configurations. Then, I introduced the first experimental realization of a true single photon carrying OAM stored via EIT in a cold atomic ensemble. The experiment shows that the non-classical correlated properties between trigger photon and retrieved photon are still retained. The structured profile between input and retrieved photons are strongly similar, giving a high memory fidelity. Most important, the single-photon’s spatial coherence during storage exhibits in good-preservation. The resulting data shows that the cold atoms quantum memory has a ability to store spatial structure at the single-photon-level, which opens the possibility for high-dimensional quantum memories.