Role of dynamics of the population inversion in attosecond pulse amplification in the active medium of a plasma-based X-ray laser dressed by an optical laser field

Abstract

We study the role of dynamics of the population inversion of an active medium of an X-ray laser dressed by a strong infrared (IR) laser field in the amplification of an attosecond pulse train produced via high-harmonic (HH) generation by the same IR field. We derive an analytical solution for the case of a recombination hydrogen-like X-ray laser, which shows that the time dependence of the population inversion strongly affects the level of the HH amplification and the envelope of the amplified attosecond pulse train. The possibilities for experimental implementation are discussed for the case of C5+ X-ray laser with the transition wavelength ∼ 3.4 nm in the “water window” range.