Engineering chiral light--matter interaction in photonic crystal   waveguides with slow light
  We design photonic crystal waveguides with efficient chiral light--matter interfaces that can be integrated with solid-state quantum emitters. By using glide-plane-symmetric waveguides, we show that chiral light-matter interaction can exist even in the presence of slow light with slow-down factors of up to $100$ and therefore the light--matter interaction exhibits both strong Purcell enhancement and chirality. This allows for near-unity directional $\beta$-factors for a range of emitter positions and frequencies. Additionally, we design an efficient mode adapter to couple light from a standard nanobeam waveguide to the glide-plane symmetric photonic crystal waveguide. Our work sets the stage for performing future experiments on a solid-state platform. 
Sahand Mahmoodian and Kasper Prindal-Nielsen and Immo S\"ollner and   S{\o}ren Stobbe and Peter Lodahl
physics.optics quant-ph