Dark Bogolon-Excitons in a Linear Atomic Super-Lattice

TL;DR

This paper explores dark and bright excitons in a linear atomic super-lattice coupled to a nanophotonic waveguide, revealing new ways to excite dark states via polariton interactions and dark bogolon-excitons.

Contribution

It introduces a novel mechanism coupling dark and bright excitons through kinematic interactions, enabling controllable excitation of dark states in super-lattices.

Findings

Dark and bright excitons naturally occur in the super-lattice.

Kinematic interactions couple dark and bright excitons.

Dark bogolon-excitons are generated via polariton scattering.

Abstract

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.