Analytic Description of the High-Energy Plateau in Harmonic Generation by Atoms: Can the Harmonic Power Increase with Increasing Laser Wavelengths?

Abstract

Frolov, M. V.; Manakov, N. L.; Sarantseva, T. S.; Emelin, M. Yu.; Ryabikin, M. Yu.; and

Adiabatic-limit Coulomb factors for photoelectron and high-order-harmonic spectra

“…Thus, the contribution to the Coulomb integral from the returning path is mostly real and therefore is not expected to have a significant effect on HHG and ATI spectra. This qualitative analysis is supported by the fairly good agreement of calculated TDSE results with analytic results [42][43][44][45][46], in which the Coulomb effects are accounted for heuristically in the ionization and recombination (or rescattering) steps. Below, we focus on the Coulomb correction for HHG spectra.…”

“…The generalization of its results to the case of atoms has been achieved heuristically (see, e.g., Refs. [42][43][44][45][46]) in the tunneling limit, γ → 0, where γ is the adiabaticity parameter introduced by Keldysh [18] [see Eq. (6) below].…”

Scaling laws for high-order-harmonic generation with midinfrared laser pulses

“…The TDSE numerical results show that with increasing λ, Y decreases slightly faster than the λ −5 behavior predicted by our analytical result (27). Specifically, fits to the TDSE data of a wavelength dependence ∝ λ −μ for two ranges of the harmonic energies ∈ [20,50] and ∈ [40,70] (eV) find that μ = 5.1 and μ = 5.3, respectively, as shown by the two curves in Fig. 2.…”

“…If the ponderomotive energy U p is kept fixed instead of the intensity, the HHG yield decreases exponentially with λ [19]. In contrast to these two cases, however, if harmonic energies are not fixed, the HHG yield for a fixed intensity may even increase with increasing wavelength λ due to atomic structure effects [20].…”

“…(20), two frequency scalings can be obtained for the averaged EWP in the low-frequency limit (cf. Ref.…”