On the theory of frequency chirped pulse coherent amplification in inhomogeneously broadened gain medium

Abstract

Frequency chirped pulse interaction with inhomogeneously broadened two-level active medium when the pulse width is shorter than the homogeneous relaxation time T2 (coherent interaction) is studied theoretically. It is shown that, unlike the case of incoherent interaction when only half an energy stored can be converted into field, in the nonlinear coherent regime full extraction of active medium energy is possible. The analogy of the effect with Landau–Zener transition between crossing molecular curves is pointed out. Giving high-energy output at relatively low peak intensities, this nonlinear mechanism of energy extraction can be useful for excimer lasers.