基于不同物理机制的固体高次谐波产生对激光参数依赖特性的理论研究  

Theoretical study of laser parameter-dependent properties of high-orderharmonic generation in solids based on different physical mechanisms

作　　者：谢贤策 胡子健 杨志红[3] 王允辉 蒋士成 XIE Xiance;HU Zijian;YANG Zhihong;WANG Yunhui;JIANG Shicheng(College of Electronic and Optical Engineering,College of Fleible Electronics(Future Technology),Nanjing University of Posts and Telecommunications,Nanjing 210023,China;State Key Laboratory of Precision Spectroscopy,East China Normal University,Shanghai 200241,China;College of Science,Nanjing University of Posts and Telecommunications,Nanjing 210023,China)

机构地区：[1]南京邮电大学电子与光学工程学院柔性电子(未来技术)学院,南京210023 [2]华东师范大学精密光谱科学与技术国家重点实验室,上海200241 [3]南京邮电大学理学院,南京210023

出　　处：《华东师范大学学报（自然科学版）》2024年第3期101-112,共12页Journal of East China Normal University(Natural Science)

基　　金：华东师范大学人才队伍建设经费。

摘　　要：高次谐波产生(high-order harmonic generation,HHG)机制的研究,主要集中在带间极化和带内电流,以及由Berry曲率引起的反常电流机制上.将强激光诱导完整电流分解为不同机制的贡献,得到长期以来被忽视的混合项电流.通过数值求解半导体Bloch方程(semiconductor Bloch equation,SBE),研究了不同机制产生高次谐波的峰值振幅和激光波长相关性,探索了各电流机制之间的相干性.研究发现,无论是随着波长变化还是随着峰值振幅的变化,混合项电流与带间极化电流诱导的高次谐波谱有着十分相似的变化规律,以及极其接近的谐波强度;同时发现Berry曲率诱导的反常谐波只能产生垂直于激光场偏振方向的偶次谐波,且在波长和峰值强度变化过程中出现的极小值是反常谐波独有的特征.通过分析不同机制之间的干涉作用,发现带间极化谐波与带内谐波(包括反常谐波)在垂直偏振方向上发生了明显的相互干涉,而混合项谐波与带内谐波的相干则微乎其微.In the study of high-order harmonic generation mechanisms,the main focus has been on interband polarization and intraband currents,as well as anomalous current mechanisms caused by Berry curvature.The long-neglected mixture term currents have been obtained by decomposing the strong laser-induced intact currents into contributions from different mechanisms.In this study,the peak amplitude and laser wavelength dependence of the high harmonics generated by different mechanisms were investigated by numerically solving the semiconductor Bloch equations(SBE).The interference between the current mechanisms was explored.It was found that the high-order harmonic spectra induced by the mixture term currents and the interband polarization currents have extremely similar variation patterns and extremely close harmonic intensities,both with the change in wavelength and the change in peak amplitude.Additionally,the anomalous harmonics were found to produce only even harmonics perpendicular to the polarization direction of the laser field.The anomalous harmonics are unique in that they have a minimum during wavelength and peak intensity variations.Analyzing the interference effects between the different mechanisms revealed that the interband polarization harmonics and intraband harmonics(including anomalous harmonics)interfere significantly with each other in the vertical polarization direction,while the interference of mixture term harmonics with intraband harmonics is negligible.

关 键 词：高次谐波产生 Berry曲率 激光诱导电流 量子相干 

分 类 号：O437[机械工程—光学工程]