Hard x-ray emission in high intensity femtosecond laser-target interaction

Abstract

Hard x-ray spectra (10-100 keV) created in high contrast, 400 fs, laser pulse interaction with solid targets, have been studied for laser intensities in the 1017-1019W/cm2 range. The target atomic numbers (Z) extended from Z = 13 to Z = 73. The measured conversion efficiency at Ag Kα emission line was 10-3% at 5 × 1018W/cm2. It has been confirmed that the hot electron temperature increased as (Iλ2)1/3 and the fraction of laser energy in hot electrons follows scaling law of (Iλ2)3/4. © 1999 American Institute of Physics.