Fig. 1. (a) Concept of post-compression with the thin-film compressor (TFC) with spectral broadening occurring due to self-phase modulation (SPM) within the thin films followed by re-compression on the resulting chirped pulse through appropriate dispersion management (DM). (b) Pulse spectra starting from a 14 J pulse initially at 22 fs duration (gray) compared with the subsequent spectrally broadened spectrum (blue) that supports a 9-fs pulse duration after DM that provides compensation for the group delay dispersion of –70 fs² (green). (c) Pulse average intensity across the beam profile for the original input pulse (gray), the chirped pulse that exits the thin films (red dotted), and the compensated pulse (blue).

Fig. 2. Experimental layout within the Long Focal Area (LFA) of the APOLLON facility. The beam is transported under vacuum from the laser room until exiting the interaction chamber for the adjacent laser diagnostic table. Within the figure, the elements described within the text are labeled by the following acronyms: thin films (TF), spherical mirror (SM), target chamber center (TCC), reflection from uncoated fused silica substrates installed as attenuators (AT), beamsplitters (BS), near-field and far-field beam imaging (IM), off-axis parabola (AOP), vacuum window (VW), wedge pair (W), dispersion, or chirped, mirrors (CM), spectrometer (SP), WIZZLER (WZ), and autocorrelator (AC).

Fig. 3. (a) Measured focus images and (b) pulse spectra. In (a), the left image shows the reference focus with no glass films in the beam path and the right image shows the focus after the thin films have been installed. For (b), the red spectrum is the average of two initial shots that result when the input pulse is chirped before entering the glass films and leads to no broadening due to the decrease in the pulse intensity. The blue spectrum shows the average value of 36 shots when the input pulse duration is optimized to 22 fs duration with maximum pulse intensity so that nonlinear spectral broadening occurs in the plate. The red and blue shaded regions represent their respective standard deviations.