OPTICS AND NUCLEAR PHYSICS

Two-electron scenario of high-order harmonics generation by atom in an intense infrared field and attosecond pulse

A. A. Romanov^ab, A. A. Silaev^a, N. V. Vvedenskii^acb, M. V. Frolov<sup>cb

a</sup> Gaponov-Grekhov Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, 603950 Russia
^b Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, 603950 Russia
^c Voronezh State University, Voronezh, 394018 Russia

Abstract: The two-electron scenario is proposed for the high-order harmonic generation (HHG) by an atom interacting with an intense infrared field and attosecond pulse. The two-electron dynamics involved in the proposed scenario is realized for the specific attosecond pulse, which can excite the resonance between the valence and deeper shells. Within the numerical solution of the time-dependent Kohn–Sham equations, we analyze the contribution of the single [Phys. Rev. A 98, 063433 (2018)] and two-electron scenarios of HHG by decreasing the duration of attosecond pulse having carrier frequency detuned from the atomic resonance. Favorable conditions are formulated for the realization of a two-electron scenario, which causes the enhancement of the harmonic yield in the spectral range exceeding the cutoff energy of the HHG spectrum in the infrared field.

Received: 23.11.2023
Revised: 08.12.2023
Accepted: 08.12.2023

DOI: 10.31857/S1234567824030054

 English version: Journal of Experimental and Theoretical Physics Letters, 2024, 119:3, 179–185