High-order harmonic spectroscopy for probing intraband and interband dynamics

Regarding the high-order harmonic generation (HHG) of solids, the intra- and interband contributions have been disputed for over a decade now. The prior scheme in this context has been limited to resolve the temporal HHG profile. In this work we propose that the real-space intra- and intercell dynamics in crystal structure respectively correspond to the reciprocal-space inter- and intraband dynamics. Thus, we utilize the polarization-resolved symmetry of the HHG yield to clarify its dominant term among the inter- and intraband contributions. For simplicity, we necessarily exclude the impact of the propagation effect and therefore take the monolayer MoS2 as the representative target material. Robustness of this correspondence scheme has been demonstrated by distinguishing the dominant contribution in the parallel HHG spectra. According to the change of the symmetry in the polarization-resolved harmonic yields, in the case of the tuning carrier distribution the transition of the dominant term between intra- and interband contributions has been verified. This work paves an alternative way to resolve the intra- and interband dynamics based on the structural symmetries of the atomic layer materials.