Ionization phenomena are shown to modify the soliton propagation dynamics of high-peak-power laser pulses in hollow-core photonic-crystal fibers (PCFs). Based on the numerical solution of the pulse-evolution equation for a high-peak-power laser field in an ionizing gas medium in a hollow PCF, we demonstrate that hollow PCFs filled with gases having high ionization potentials $I_p$ can support soliton transmission regimes for gigawatt femtosecond laser pulses. In hollow PCFs filled with low-$I_p$ gases, on the other hand, the ionization-induced change in the refractive index of the gas leads to a blueshifting of soliton transients, pushing their spectrum beyond the point of zero group-velocity dispersion, thus preventing the formation of stable high-peak-power solitons.

• Received 15 March 2007

DOI:https://doi.org/10.1103/PhysRevA.76.013820