Figure 1

(Color online) Group-velocity dispersion (solid line) as a function of the wavelength for a hollow-core PCF shown in the inset. Also shown are the spectra of amplified femtosecond Ti: sapphire laser pulses used as a PCF input in experiments (filled circles) and simulations (dashed curve). Inset 1 shows the ionization-induced change in the refractive index $\delta n_{\mathrm{p}}$ of an atmospheric-pressure air in the field of a laser pulse (shown by the dashed line) with a peak intensity of $5.0\times {10}^{13}\mathrm{W}{\mathrm{cm}}^{-2}$. Inset 2 presents a scanning electron microscope image of the hollow-core PCF.Reuse & Permissions

Figure 2

(Color online) Temporal (a), (b) and spectral (c) dynamics of a laser pulse propagating in a hollow PCF filled with an atmospheric-pressure gas. The input pulse intensity is (a) $3.0\times {10}^{12}\mathrm{W}∕{\mathrm{cm}}^2$ and (b), (c) $5.0\times {10}^{13}\mathrm{W}∕{\mathrm{cm}}^2$. The initial pulse width is $60\mathrm{fs}$.Reuse & Permissions

Figure 3

(Color online) Spectra of amplified Ti: sapphire laser pulses measured at the input (open circles) and at the output (filled circles) of the hollow-core PCF with a length of $5\mathrm{cm}$. The initial pulse width is $60\mathrm{fs}$. The input pulse intensity is $5\times {10}^{13}\mathrm{W}∕{\mathrm{cm}}^2$. The dashed line shows the results of numerical simulations. Transmission spectrum of the hollow PCF is shown by the dash-dotted line. The inset presents the pulse shape of the PCF output: (solid and dashed lines) results of numerical simulations and (filled and open circles) reconstruction from cross-correlation measurements. The input pulse intensity is (open circles and dashed line) $3.0\times {10}^{12}\mathrm{W}∕{\mathrm{cm}}^2$ and (filled circle and solid line) $5.0\times {10}^{13}\mathrm{W}∕{\mathrm{cm}}^2$.Reuse & Permissions