Nonlinear dynamics of electromagnetic field and valley polarization in WSe2 monolayer
Nonlinear dynamics of electromagnetic field and valley polarization in WSe2 monolayer
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DOI：
10.1063/5.0077235
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发表时间：
2021-11
影响因子：
4
通讯作者：
Arqum Hashmi;S. Yamada;A. Yamada;K. Yabana;T. Otobe
中科院分区：
文献类型：
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作者：
Arqum Hashmi;S. Yamada;A. Yamada;K. Yabana;T. Otobe
采用二维麦克斯韦含时密度泛函方法研究了WSe 2单分子膜的线性和非线性光学响应。利用手征共振脉冲，研究了强、弱激光场中电子动力学沿着的高次谐波产生。WSe 2单分子膜在I = 10 10 W/cm处呈现线性光学响应，而在I = 10 W/cm处呈现复杂的非线性响应。在强激光场下观察到WSe_2单分子膜的可饱和吸收的非线性响应。通过改变共振光的手征性，在激发态布居中观察到强的圆二色性效应。弱激光场表现出有效的谷极化，强激光场则通过非线性过程在K（K ′）和Γ点之间产生自旋极化载流子峰。另一方面，强激光场显示高达11阶的高次谐波。结果表明，圆极化共振脉冲在WSe 2单层膜中产生3 n ±1阶高次谐波.
Linear and nonlinear optical response of WSe2 monolayer is investigated by two-dimensional Maxwell plus time-dependent density functional theory with spin-orbit interaction. By applying the chiral resonant pulses, the electron dynamics along with high harmonic generation are examined at weak and strong laser fields. WSe2 monolayer shows the linear optical response at the intensity I = 10 10 W/cm while a complex nonlinear behavior is observed at I = 10 W/cm. The nonlinear response of WSe2 monolayer in terms of saturable absorption is observed at strong laser field. By changing the chirality of the resonant light, a strong circular dichroic effect is observed in the excited state population. A relatively weak laser field shows effective valley polarization while strong field induces spin-polarized carrier peak between K(K ′) and Γ -point via nonlinear process. On the other hand, the strong laser field shows high harmonics up to the 11th order. Our results demonstrate that circularly polarized resonant pulse generate high harmonics in WSe2 monolayer of order 3n±1.