Third-harmonic generation in an ionized gas and its relation to the residual energy of electrons

The generation of low-order harmonics by a short ionizing laser pulse passing through a gas is investigated in regard to the space-time phase-synchronism conditions. This investigation is based on the results of hydrodynamic calculations for the model of [1] supplemented by taking into account the ionization current [2–5] and on the numerical solution of a one-dimensional time-dependent Schrodinger equation. As applied to the description of the...