An improved method for the investigation of high-order harmonic generation from graphene?

• 作者: Guo-Li Wang Lu Liu Song-Feng Zhao Xiao-Xin Zhou Zhi-Hong Jiao Zhong Guan
• 来源期刊: 中国物理B（英文版）
• 年，卷（期）: 2020,（10）
• 所属期刊栏目: ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS
• 页码范围: 341-349
• 页数: 9页
• 语种: 英文
• DOI: 10.1088/1674-1056/abab76

摘要

High-order harmonic generation (HHG) of bulk crystals in strong laser field is typically investigated with semicon-ductor Bloch equations (SBEs). However, in the length gauge, it suffers from the divergence for the crystals with a zero band gap, such as graphene, using both Bloch- and Houston-states expansion methods. Here, we present a method of solv-ing the SBEs based on time-dependent Bloch basis, which is equivalent to semiconductor Bloch equations in the velocity gauge. Using this method, we investigate the HHG of a single-layer graphene. It is found that our results for population are in good agreement with the other results. For a initial condition py = 0, we find the electrons just move in single valence band or conduction band, which are in accord with classical results. Our simulations on the HHG dependence of polarization of driving laser pulse confirm that 5th, 7th, and 9th harmonic yields increase to the maximal value when laser ellipticity ε ≈ 0.3. What is more, similar to the case of atoms in the laser field, the total strength of 3rd harmonic decrease monotonically with the increase of ε. In addition, we simulate the dependence of HHG on crystallographic orientation with respect to the polarization direction of linear mid-infrared laser pulse, and the results reveal that for higher harmonics, their radiation along with the change of rotation angle θ reflects exactly the sixfold symmetry of graphene. Our method can be further used to investigate the behaviors of other materials having Dirac points (i.e., surface states of topological insulators) in the strong laser fields.

作者信息

序号	姓名	单位	发文数	被引次数	H指数	G指数
1	Zhong Guan		1	0	0.0	0.0
2	Lu Liu		1	0	0.0	0.0
3	Guo-Li Wang		1	0	0.0	0.0
4	Song-Feng Zhao		1	0	0.0	0.0
5	Zhi-Hong Jiao		1	0	0.0	0.0
6	Xiao-Xin Zhou		1	0	0.0	0.0