Conical-emission and shock-front dynamics in femtosecond laser-pulse filamentation

We investigate both experimentally and numerically the space-time dynamics of an ultrashort laser pulse during self-focusing and nonlinear propagation in water by means of a time-gated angular-spectrum characterization. The results identify the formation of shock fronts on both trailing and leading edges of the wave packet that are due to the formation of subluminal and superluminal group velocity intensity peaks, sustained by conical emission.