原子错位堆栈增强双层MoS_(2)高次谐波产率

Enhancing high harmonic generation in bilayer MoS_(2) by interlayer atomic dislocation

本文采用数值求解多能带半导体布洛赫方程组的方法开展强激光与双层MoS_(2)材料相互作用产生高次谐波的理论研究.模拟发现,T型堆栈双层MoS_(2)产生的高次谐波在高能区域的转换效率比AA型堆栈双层MoS_(2)高一个数量级.理论分析表明,由于原子级错位堆栈下晶体对称性被打破,使原有的部分带间禁戒跃迁路径被打开,带间跃迁激发通道增加,大大增大了载流子跃迁概率,从而增强了高次谐波转换效率.此外,对谐波产率的波长定标研究表明,在较长波长的激光驱动下(>2000 nm),T型堆栈下所增强的高次谐波具有更高的波长依赖.该工作为如何优化增强固体高次谐波的转换效率提供一种新思路.

In this paper,the high-order harmonic generation by the interaction between strong laser and bilayer MoS_(2) 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_(2) is one order of magnitude higher than that of AA-stacking bilayer MoS_(2).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.