Dark Bogolon-Excitons in a Linear Atomic Super-Lattice

Dark and bright excitons are shown to appear naturally in a linear atomic super-lattice with two atoms per unit cell. In bringing the super-lattice into a strong coupling regime with a one-dimensional nanophotonic waveguide, bright excitons and photons are coherently mixed to form polaritons. Treating excitons as bosons implies a mechanism that forbids two excitations from being at the same atomic state, which is included here through a bosonization procedure with kinematic interactions. Interestingly these interactions couple dark and bright excitons, and which we exploit as a new tool for exciting dark states in a controllable way. We suggest a pump-probe experiment where two polaritons scatter into two dark excitons that found to be correlated and are represented as dark bogolon-excitons. The results can be adapted for any super-lattice of active materials, e.g., of organic molecules.