ECAMP 15

Accurately reproducing the discrete spectral peaks observed in solid-state high-order harmonic generation (HHG) typically requires the explicit inclusion of dephasing effects [1, 2]. Here, we contrast numerical simulations with analytical modeling to clarify how dephasing affects both the spectral structure and the driver field dependence of the harmonics, with particular emphasis on the non-integer contributions in the plateau region. The HHG spectra are obtained both numerically, by performing a crystal-momentum resolved calculation of the time-dependent Schrödinger equation with multiple valence and conduction bands, and analytically, by implementing the semiconductor Bloch equations within a reduced two-band model treated by a saddle-point approximation [3]. From the latter, we derive closed-form expressions for the non-integer harmonics, which are in quantitative agreement with our simulations. The results shed light on the underlying electron dynamics, reveal the mechanisms that shape the HHG spectrum, and suggest concrete experimental strategies for resolving the persistent discrepancies between current theories and measurements.
[1] Vampa et al. Phys. Rev. Lett. 113, 073901 (2014)
[2] Cavaletto et al. Nat. Rev. Phys. 7, 38 (2025)
[3] Navarrete et al., Phys. Rev. A 100, 033405 (2019)