Polariton waveguides from a quantum dot chain in a nanowire photonic crystal: an architecture for quantum information science and waveguide QED

We introduce a polariton-waveguide structure, comprised of a nanowire-based photonic crystal waveguide with a quantum dot embedded in each unit cell. Using realistic designs and parameters, we derive and calculate the fundamental electromagnetic properties of these polariton waveguides, with an emphasis on the photon Green function and local optical density of states (LDOS). Both infinite and finite-size waveguides are considered, where the latter's properties are calculated using a Dyson equation approach without any approximations. We demonstrate dramatic increases, and rich fundamental control, of the LDOS due to strong light-matter interactions in each unit cell through periodic quantum dot interactions. Consequently, these structures allow the exploration of new regimes of waveguide quantum electrodynamics. As an example application, we consider the coupling of an external target quantum dot with a finite-sized polariton waveguide, and show that the single quantum dot strong coupling regime is easily accessible, even for modest dipole strengths.