Nonspreading Light Pulses in Photonic Crystals
  We investigate propagation of light pulses in photonic crystals in the vicinity of the zero-diffraction point. We show that Gaussian pulses due to nonzero width of their spectrum spread weakly in space and time during the propagation. We also find the family of nonspreading pulses, propagating invariantly in the vicinity of the zero diffraction point of photonic crystals. 
K.Staliunas, C.Serrat, R.Herrero, C.Cojocaru, J.Trull