Theory of Kα generation by femtosecond laser-produced hot electrons in thin foils

An analytical model of femtosecond Kα x-ray generation from laser-irradiated foils is presented. Expressions are found for the photon emission yield in both forward and backward directions in integral form as a function of hot-electron temperature and target thickness. It is found that for any given target material, there is a foil thickness and a hot-electron temperature at which the Kα emission is maximized. Conversion efficiencies are consistent with contemporary measurements of Kα radiation produced with femtosecond lasers