Subdiffractive pulses in photonic crystals

Photonic crystals are used to modify the properties of light propagation by introducing photonic band-gaps in radiation spectra (i.e. converting light conductors into insulators) and also by modification of the diffraction of the light. At the crossover point between positive and negative diffraction the zero diffraction point can be expected, giving rise to the effect of self-collimation. We study the subdiffractive pulse propagation by developing the normal form description in the vicinity of the zero diffraction point.