High-order harmonics generation in MoS2 nanosheets in the presence of CdSe and CdSe/V2O5 quantum dots

Engineering nonlinear optical responses in two-dimensional materials via heterostructure design is emerging as a powerful approach for next-generation photonic devices. Although perturbative nonlinear effects in these systems are well studied, their connection to nonperturbative processes such as high-harmonic generation (HHG) remains largely unexplored. Here, we investigate the HHG from few-layer MoS₂ nanosheets integrated with CdSe and passivated CdSe/V₂O₅ quantum dots (QDs). The hybrid structures exhibit pronounced enhancement in harmonic intensity and a clear extension of the harmonic cutoff relative to pristine MoS₂. We demonstrate that interfacial charge-transfer dynamics-previously associated with the dominant contribution to the third-order susceptibility χ(3) - also govern the efficiency of HHG, thereby establishing a direct link between perturbative and nonperturbative regimes in these 0D-2D hybrids. The carrier injection from the QDs increases the electron-hole population participating in HHG, while the moderated response in passivated QD systems highlights the role of interfacial potential barriers. These results provide a unified physical picture of nonlinear optical processes in hybrid nanostructures and offer design principles for enhancing coherent light generation.