Experimental program on the 20 TW laser system

Abstract

Pulses of 20 TW have been generated at 1064 nm using the chirped pulse amplification technique coupled to a 90 mm output aperture Nd–silicate glass amplification line. The chirped pulses are compressed to 1.2 psec with an energy of 24 J using large holographic gold-coated 1740 lines/mm diffraction gratings. In a first step, the beam is focused by an aspherical lens, but the maximum measured irradiance is limited to 1018 W/cm2 by self-focusing effects in the air path and in the lens. Higher values up to 1019 W/cm2 will need propagation of the compressed beam in vacuum and focusing by reflective optics. The first experiments deal with laser–plasma coupling, with emphasis on the power contrast ratio. Further plans include multiple Compton scattering and x-ray laser generation. Theoretical works on ionization processes and particle accelerator are also presented.