Understanding the dynamics of photoionization-induced nonlinear effects and solitons in gas-filled hollow-core photonic crystal fibers

Abstract

We present the details of our previously formulated model [Saleh et al., Phys. Rev. Lett. 107, 203902 (2011)] that governs pulse propagation in hollow-core photonic crystal fibers filled by an ionizable gas. By using perturbative methods, we find that the photoionization process induces the opposite phenomenon of the well-known Raman self-frequency redshift of solitons in solid-core glass fibers, as was recently experimentally demonstrated [Holzer et al., Phys. Rev. Lett. 107, 203901 (2011)]. This process is only limited by ionization losses, and leads to a constant acceleration of solitons in the time domain with a continuous blueshift in the frequency domain. By applying the Gagnon-Belanger gauge transformation, multipeak "inverted gravitylike" solitary waves are predicted. We also demonstrate that the pulse dynamics shows the ejection of solitons during propagation in such fibers, analogous to what happens in conventional solid-core fibers. Moreover, unconventional long-range nonlocal interactions between temporally distant solitons, unique of gas plasma systems, are predicted and studied. Finally, the effects of higher-order dispersion coefficients and the shock operator on the pulse dynamics are investigated, showing that the conversion efficiency of resonant radiation into the deep UV can be improved via plasma formation

Hollow-Core Fiber Technology: The Rising of “Gas Photonics”

“…Therefore, in HCPCF this phenomenon appears for lower laser average power values than the one required in simple capillaries in high field domain. This ionization process is intrinsically linked to a loss decrease [129,130].…”

“…Good agreement has been obtained between experiments and numerical simulations when an ionization term is taken into account in the model in term of spectral evolution and also in the energy losses. Further, the theoretical explanations of this blue-shift effect have been deeply developed in References [130,134].…”

Dynamics of blueshifted floating pulses in gas-filled hollow-core photonic crystal fibers

“…The model introduced in [4,5] for pulse propagation in nonlinear gaseous media presenting Kerr and plasma nonlinearities has the following dimensionless version i ∂q ∂ξ + 1 2…”

Breathers in a hollow-core photonic crystal fiber

“…, where k 0 = ω 0 /c with c being the speed of light and ω 0 is the input pulse central frequency, σ is related to two constants [14], ω T is the maximum plasma frequency, A eff is the effective mode area and γ K is the nonlinear Kerr coefficient of the gas.…”