I will present our progress towards the demonstration of passive state transfer from a single photon to a single atom, and vice versa. The scheme relies on Single-Photon Raman Interaction (SPRINT), proposed by a series of theoretical works [1-5], in which the coupling between a three-level L-system and a single-mode waveguide results in the swapping of a flying qubit, encoded in the polarization of the photon, with a stationary qubit, encoded in the two ground states of the atom.
Beyond acting as a passive quantum memory, SPRINT can be modified to perform as a universal quantum gate (√SWAP) , without any need for optical or RF control fields.
In the first experimental realization of SPRINT , the state of the atom was shown to be determined by the direction of an incoming single-photon pulse sent through the fiber. The state of the atom was then read by a subsequent photon, thereby realizing all-optical switching of single photons by single photons. We then applied this scheme for demonstrating deterministic single-photon extraction from an incoming pulse with an arbitrary number of photons . This scheme, which can be implemented with any atom-like three-level L system, provides a building block for scalable quantum networks based on completely passive nodes, interconnected and activated solely by single photons.