Bifurcating trajectory of non-diffractive electromagnetic Airy pulse
  The explicit expression for spatial-temporal Airy pulse is derived from the Maxwell's equations in paraxial approximation. The trajectory of the pulse in the time-space coordinates is analysed. The existence of a bifurcation point that separates regions with qualitatively different features of the pulse propagation is demonstrated. At this point the velocity of the pulse becomes infinite and the orientation of it changes to the opposite. 
Alexander G. Nerukh, Denis A. Zolotariov, Dmitry A. Nerukh
physics.optics