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arXiv · 2112.12951

Effect of incoherent electron-hole pairs on high harmonic generation in an atomically thin semiconductor

Kohei Nagai·Kento Uchida·Satoshi Kusaba·Takahiko Endo·Yasumitsu Miyata·Koichiro Tanaka
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Abstract

High harmonic generation (HHG) in solids reflects the underlying nonperturbative nonlinear dynamics of electrons in a strong light field and is a powerful tool for ultrafast spectroscopy of electronic structures. Photo-carrier doping allows us to understand the carrier dynamics and the correlations between the carriers in the HHG process. Here, we study the effect of incoherent electron-hole pairs on HHG in an atomically thin semiconductor. The experimentally observed response to photo-carrier doping is successfully reproduced in numerical simulations incorporating the photo-excited carrier distribution, excitonic Coulomb interaction and electron-electron scattering effects. The simulation results reveal that the presence of photo-carriers enhances the intraband current that contributes to high harmonics below the absorption edge. We also clarify that the excitation-induced dephasing process rather than the phase-space filling effect is the dominant mechanism reducing the higher order harmonics above the absorption edge. Our work provides a deeper understanding of high harmonic spectroscopy and the optimum conditions for generating extreme ultraviolet light from solids.

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Kohei Nagai, Kento Uchida, Satoshi Kusaba, Takahiko Endo, Yasumitsu Miyata, Koichiro Tanaka. 2021-12-24. Effect of incoherent electron-hole pairs on high harmonic generation in an atomically thin semiconductor. https://arxiv.org/abs/2112.12951

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