From Single Atoms to Engineered “Super-Atoms”: Interfacing Photons and Atoms in Free Space

Figure 10

Atoms with three excited substates , , and , a ground state , and a long lived state are arranged in a regular lattice. The state is coupled to the state by a classical laser field. The excited states decay to the ground state emitting a photon with , , and polarized photons, respectively. The direction of the emission is determined by the wave number of the atomic coherence and the wave number of the out-coupling field, .