Focusability of laser pulses at petawatt transport intensities in thin-film compression

Thin-film compression (TFC) and the focusability of high-power laser pulses after self-phase modulation in thin films at transport intensities (∼1 TW∕cm ² ) for petawatt laser systems is demonstrated. High-energy (∼296 mJ) laser pulses are compressed from ∼55 fs to ∼31 fs. Additionally, the focusability of high-power (∼45–55 TW) flat-top laser pulses after spectral broadening in thin films is found to be largely maintained, showing only modest decreases in the energy contained in the central part of the focal spot. In light of these findings, TFC offers a method for moving toward single-cycle pulse durations at significantly higher energies than those found at present, and if beam instabilities can be mitigated, maybe even higher intensities.