Wavelength dependence of the cutoff energy for high-order harmonic generation from a doped system
Phys. Rev. A 112, 053519 – Published 19 November, 2025
DOI: https://doi.org/10.1103/p58g-6mk7
Abstract
The cutoff energy of high-order harmonics generation (HHG) in doped systems is investigated theoretically with the different laser wavelengths. Our study reveals that in the doped system, when driven by lasers with wavelengths ranging from to , the cutoff energy exhibits three distinct regimes: linear dependence on wavelength, rapid enhancement, and wavelength independence. In the regime where the cutoff energy exhibits linear dependence on the wavelength, interband transitions between localized electron states and the conduction bands dominate the cutoff of HHG in the doped system, with the cutoff energy being significantly higher than that of HHG in the pristine crystal. When the cutoff energy increases rapidly with wavelength, interband transitions involving valence band states and the second and third conduction bands govern the HHG cutoff energy. In the wavelength-independent regime, the intensity of intraband HHG increases rapidly: electrons tend to move within the same band rather than transiting between different bands, causing LES to lose the advantage in modulating interband processes. Consequently, the doped system no longer exhibits the higher HHG cutoff energy relative to the pristine crystal. This work explores the correlation between HHG in doped systems and the laser wavelength, providing a theoretical basis for the modulation of HHG through doping.
