Multiharmonic Spanning Nonlinear X -wave: An Asymptotic State of Extreme Long Wave Infrared Dispersive Shock Regularization

We predict the emergence of novel X-waves emitted as a consequence of extreme dispersive shock regularization of an intense long wave few cycle pulse propagating through a weakly dispersive medium. This robust propagation-invariant solution to Maxwell's equations appears as the asymptotic state in the high harmonic conversion when the pump propagates in a strongly nonlinear weakly dispersive regime, while the weakly nonlinear conical emission is dominated by chromatic dispersion.