Slow light in dielectric composite materials of metal nanoparticles
  We propose a method for slowing down light pulses by using composites doped with metal nanoparticles. The underlying mechanism is related to the saturable absorption near the plasmon resonance in a pump-probe regime, leading to strong dispersion of the probe refractive index and significantly reduced group velocities. By using the non-collinear scheme, it is possible to realize the total fractional delay of 43 or larger values. This scheme promises simple and compact slow-light on-chip devices with tunable delay and THz bandwidth. 
Kwang-Hyon Kim, Anton Husakou, Joachim Herrmann
physics.optics