High-harmonic generation in monolayer WSe2 under photo-carrier doping

Solid-state high-harmonic generation (HHG) is the most striking process that reflects emergent coherent electron dynamics under strong infrared laser field [1] - [4] . The microscopic origin of HHG is often theoretically separated into two contributions, i.e., intraband current and interband polarization [1] - [4] . To disentangle these two contributions experimentally, Z. Wang et al. proposed a useful concept, the photo-carrier doping effect on HHG [2] . They experimentally demonstrated the effect on bulk ZnO. However, light propagation in a thick sample generally gives extrinsic side effects called propagation effects and makes it difficult to understand the microscopic electronic dynamics. To avoid such a difficulty, atomically thin materials are the ideal experimental platform [3] .