Ultra Low-Power All-Optical Switching
  Using analytical modeling and detailed numerical simulations, we investigate properties of hybrid systems of Photonic Crystal micro-cavities which incorporate a highly non-linear Ultra Slow Light medium. We demonstrate that such systems, while being miniature in size (order wavelength), and integrable, could enable ultra-fast non-linear all-optical switching at single photon energy levels. 
Marin Soljacic, Elefterios Lidorikis, J.D.Joannopoulos, and Lene   Vestergaard Hau