Enhancing high harmonic generation in bilayer MoS<sub>2</sub> by interlayer atomic dislocation

Abstract

In this paper, the high-order harmonic generation by the interaction between strong laser and bilayer MoS<sub>2</sub> material is studied by numerically solving the multi-band semiconductor Bloch equations. It is found that the conversion efficiency of high-order harmonics generated by T-stacking bilayer MoS<sub>2</sub> is one order of magnitude higher than that of AA-stacking bilayer MoS<sub>2</sub>. The theoretical analysis shows that due to the breaking of crystal symmetry under the atomic level dislocation, part of the interband forbidden transition paths are opened, and the excitation channels of interband transition are increased, which greatly increases the carrier transition probability and enhances the high-order harmonic conversion efficiency. In addition, the study of wavelength scaling of harmonic yield shows that the enhanced high-order harmonics in T-stacking bilayer are better wavelength-dependent under the action of a long wavelength laser (> 2000 nm). This work provides a new idea of how to optimize and enhance the conversion efficiency of solid-state high-order harmonics.