Commissioning experiment of the high-contrast SILEX-II multi-petawatt laser facility

The results of a commissioning experiment on the SILEX-II laser facility (formerly known as CAEP-PW) are reported. SILEX-II is a complete optical parametric chirped-pulse amplification laser facility. The peak power reached about 1 PW in a 30 fs pulse duration during the experiment. The laser contrast was better than 10(10) at 20 ps ahead of the main pulse. In the basic laser foil target interaction, a set of experimental data were collected, including spatially resolved x-ray emission, the image of the coherent transition radiation, the harmonic spectra in the direction of reflection, the energy spectra and beam profile of accelerated protons, hot-electron spectra, and transmitted laser energy fraction and spatial distribution. The experimental results show that the laser intensity reached 5 x 10(20) W/cm(2) within a 5.8 mu m focus (FWHM). Significant laser transmission did not occur when the thickness of the CH foil was equal to or greater than 50 nm. The maximum energy of the accelerated protons in the target normal direction was roughly unchanged when the target thickness varied between 50 nm and 15 mu m. The maximum proton energy via the target normal sheath field acceleration mechanism was about 21 MeV. We expect the on-target laser intensity to reach 10(22) W/cm(2) in the near future, after optimization of the laser focus and upgrade of the laser power to 3 PW.& nbsp;(C) 2021 Author(s).