Controlled cavity QED and single-photon emission using a photonic-crystal waveguide cavity system

We introduce a photonic crystal waveguide-cavity system for controlling single-photon cavity quantum electrodynamics (QED). Exploiting Bloch mode analysis and medium-dependent Green function techniques we demonstrate that the propagation of single photons can be accurately described analytically for integrated periodic waveguides with little more than four unit cells, including an output coupler. We verify our analytical approach by comparing to rigorous numerical calculations for a range of photonic crystal waveguide lengths. The semiconductor-based nanophotonics system allows one to nanoengineer various regimes of cavity QED with unprecedented control. We demonstrate maximum Purcell factors of greater than 500 and on-chip single-photon beta factors of about 80% efficiency. Both weak and strong-coupling regimes are investigated, and the important role of waveguide length on the output emission spectra is shown for vertically emitted emission and output waveguide emission.