High-order harmonic generation from a two-dimensional band structure
High-order harmonic generation from a two-dimensional band structure
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DOI：
10.1103/physreva.97.043420
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发表时间：
2018-04
影响因子：
2.9
通讯作者：
J. Jin;Xiang-Ru Xiao;Haojun Liang;Mu-Xue Wang;Si-Ge Chen;Q. Gong;Liang-You Peng
中科院分区：
文献类型：
--
作者：
J. Jin;Xiang-Ru Xiao;Haojun Liang;Mu-Xue Wang;Si-Ge Chen;Q. Gong;Liang-You Peng
在过去的几年里，固体中的谐波产生引起了人们极大的关注。近年来，人们开展了一些二维单层或少层材料的实验研究。这些研究表明，在二维情况下，谐波产生显示出强烈的依赖于激光的取向和椭圆率，这需要一个定量的理论解释。本文基于含时薛定谔方程的数值解，对二维能带结构中的谐波产生进行了系统的研究。通过与一维情况的比较，我们发现，由于二维能带结构中存在许多交叉点，生成动力学可以有显着的差异。特别地，较高的导带可以通过这些交叉点被逐步激发，并且谐波的总贡献由导带到价带的不同簇之间的跃迁的混合给出。我们还提出了谐波产额对激光偏振方向的取向依赖性。
In the past few years, harmonic generation in solids has attracted tremendous attention. Recently, some experiments of two-dimensional (2D) monolayer or few-layer materials have been carried out. These studies demonstrated that harmonic generation in the 2D case shows a strong dependence on the laser's orientation and ellipticity, which calls for a quantitative theoretical interpretation. In this work, we carry out a systematic study on the harmonic generation from a 2D band structure based on a numerical solution to the time-dependent Schr\"odinger equation. By comparing with the 1D case, we find that the generation dynamics can have a significant difference due to the existence of many crossing points in the 2D band structure. In particular, the higher conduction bands can be excited step by step via these crossing points and the total contribution of the harmonic is given by the mixing of transitions between different clusters of conduction bands to the valence band. We also present the orientation dependence of the harmonic yield on the laser polarization direction.