检索结果-内蒙古大学图书馆

Orientation dependence of high-order harmonic generation in graphene

Physical Review A 2021年第3期104卷 033110-033110页

作者： Yuntian Zhang Liang Li Jiapeng Li Tengfei Huang Pengfei Lan Peixiang Lu School of Physics and Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology Wuhan 430074 China Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan 430205 China CAS Center for Excellence in Ultra-intense Laser Science Shanghai 201800 China

We investigate the orientation dependence of high-order harmonic generation (HHG) in graphene by solving the semiconductor Bloch equations. The tight-binding approximation including up to the third-nearest-neighbor atoms is used to model the graphene. Our simulations show that the orientation dependence of HHG shows different patterns for different harmonics. With increasing the laser intensity, these patterns become similar except for a double-peak structure shown in lower-order harmonics. The double-peak structure appears at high laser intensity due to the contribution of the harmonic perpendicular to the laser polarization direction. The harmonic yield is decomposed as the contributions of the nearest-neighbor interaction, the second-nearest-neighbor interaction, and the third-nearest-neighbor interaction. Our results show that the harmonic yields are mainly contributed by the nearest-neighbor interaction, but the third-nearest-neighbor interaction also plays an important role and modifies the orientation dependence.

关键词： Density functional theory Light-matter interaction Multiphoton or tunneling ionization & excitation Nonlinear optics Strong electromagnetic field effects Ultrafast optics Ultrafast phenomena

来源：评论

学校读者我要写书评

暂无评论

Electron-wave-packet-deformation–induced attosecond emission time shift in gas high-order harmonic generation

引用

Physical Review A 2024年第2期109卷 023121-023121页

作者： Sen Qiao Liang Li Pengfei Lan Peixiang Lu Wuhan National Laboratory for Optoelectronics and School of Physics Huazhong University of Science and Technology Wuhan 430074 China Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan 430205 China CAS Center for Excellence in Ultra-Intense Laser Science Shanghai 201800 China

The laser-induced recollision of electron trajectories is usually used to describe high-order harmonic generation (HHG), which also lays the foundation for high-order harmonic spectroscopy. Electron trajectory models based on the saddle-point approximation are conceptually similar to the light ray model in optics. Considering that ray optics is not complete to explain all wave optics phenomena, we revisit the validity of trajectory models when incorporating the Coulomb potential. Results show that, under commonly used gas HHG experimental conditions, both the classical three-step model and the quantum orbit model have dozens or hundreds of attoseconds of deviation in emission time. By using the Gaussian wave-packet method, we reveal that the time shift can be attributed to the deformation of the recollision electron wave packet. Wave-packet deformation is an inherent wavelike phenomenon caused by group delay dispersion and higher-order dispersion, and thereby is difficult to modify by particlelike trajectories. In addition, we reveal the notable influence of wave-packet deformation on observables in two-color field HHG experiments.

关键词： Atomic & molecular processes in external fields Strong-field-induced spectra XUV generation

来源：评论

学校读者我要写书评

暂无评论

Dynamic Core Polarization in High Harmonic Generation from Solids: The Example of MgO Crystals

引用

Physical Review Letters 2021年第18期126卷 187401-187401页

作者： Liang Li Yinfu Zhang Pengfei Lan Tengfei Huang Xiaosong Zhu Chunyang Zhai Ke Yang Lixin He Qingbin Zhang Wei Cao Peixiang Lu Wuhan National Laboratory for Optoelectronics and School of Physics Huazhong University of Science and Technology Wuhan 430074 China Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan 430205 China CAS Center for Excellence in Ultra-intense Laser Science Shanghai 201800 China

Previously, the strong field processes in solids have always been explained by the single-active-electron (SAE) model with a frozen core excluding the fluctuation of background electrons. In this work, we demonstrate the strong field induced dynamic core polarization effect and propose a model for revealing its role in high harmonic generation (HHG) from solids. We show that the polarized core induces an additional polarization current beyond the SAE model based on the frozen cores. It gives a new mechanism for HHG and leads to new anisotropic structures, which are experimentally observed with MgO. Our experiments indicate that the influences of dynamic core polarization on HHG are obvious for both linearly and elliptically polarized laser fields. Our work establishes the bridge between the HHG and the dynamic changes of the effective many-electron interaction in solids, which paves the way to probe the ultrafast electron dynamics.

关键词： Crystal structure Materials Strong electromagnetic field effects High-harmonic generation Laser annealing optical absorption spectroscopy Semiclassical methods

来源：评论

学校读者我要写书评

暂无评论

Resolving the polarization of high-order harmonic generation by temporal multislit interferometry

引用

Physical Review A 2021年第2期104卷 023114-023114页

作者： Sen Qiao Liang Li Xiaosong Zhu Pengfei Lan Peixiang Lu School of Physics and Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology Wuhan 430074 China Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan 430205 China CAS Center for Excellence in Ultra-intense Laser Science Shanghai 201800 China

We propose a temporal multislit interference model of high-order harmonic generation (HHG). By using the interference picture, we investigate the polarization features of harmonics generated by atoms and the two-dimensional synthesized driving laser fields. The result shows that the selection rules and ellipticity of harmonics can be understood by intracycle interference. Based on quantum path analysis, we show the harmonic polarization can be controlled by modifying the structure of the temporal interferometer. We perform a quantitative analysis of the harmonic polarization spectrum in terms of electron dynamics and provide an intuitive picture and a general tool for HHG investigation.

关键词： Atomic & molecular processes in external fields High-order harmonic generation

来源：评论

学校读者我要写书评

暂无评论

Picometer-Resolved Photoemission Position within the Molecule by Strong-Field Photoelectron Holography

引用

Physical Review Letters 2021年第26期127卷 263202-263202页

作者： Wenhai Xie Jiaqing Yan Min Li Chuanpeng Cao keyu Guo Yueming Zhou Peixiang Lu Wuhan National Laboratory for Optoelectronics and School of Physics Huazhong University of Science and Technology Wuhan 430074 China Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan 430205 China CAS Center for Excellence in Ultra-intense Laser Science Shanghai 201800 China

Laser-induced tunneling ionization is one of the fundamental light-matter interaction processes. An accurate description of the tunnel-ionized electron wave packet is central to understanding and controlling subsequent electron dynamics. Because of the anisotropic molecular structure, tunneling ionization of molecules involves considerable challenges in accurately describing the tunneling electron wave packet. Up to now, some basic properties of the tunneling electron from molecules still remain unexplored. Here, we demonstrate that the tunneling electron from a molecule is not always emitted from the geometric center of the molecule along the tunnel direction. Rather, the photoemission position depends on the molecular orientation. Using a photoelectron holographic technique, we determine the photoemission position for a nitrogen molecule relative to the molecular geometric center to be 95±21 pm when the molecular axis is oriented along the tunnel direction. Our Letter poses, and answers experimentally, a fundamental question as to where the molecular photoionization actually begins, which has significant implications for time-resolved probing of valence electron dynamics in molecules.

关键词： Multiphoton or tunneling ionization & excitation Photoemission Ultrafast phenomena

来源：评论

学校读者我要写书评

暂无评论

High-purity valley-polarized currents induced by bichromatic optical fields in two-dimensional materials

arXiv

引用

arXiv 2024年

作者： Li, Wenqing Zhu, Xiaosong Li, Liang He, Wanzhu Long, Jie Lan, Pengfei Lu, Peixiang Wuhan National Laboratory for Optoelectronics School of Physics Huazhong University of Science and Technology Wuhan430074 China Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan430205 China Hubei Optical Fundamental Research Center Wuhan430074 China

Producing currents predominantly from a single valley, namely valley-polarized currents, at optical-cycle timescales is an important aspect of the petahertz valleytronics, yet it remains less developed. This work exhibits the feasibility of achieving this goal using bichromatic optical fields, which allow for the precise control of sub-cycle electron dynamics. The combined effect of the helical and asymmetric waveforms of the optical fields leads to highly asymmetric excitation at different valleys and displacement of the excited electrons concurrently, thereby inducing valley-polarized currents with high valley purity, on the sub-optical-cycle timescale. Inherently, the purity of the currents built up from the optical approach remains high even for materials with short decoherence time. Moreover, the direction of the currents can be precisely controlled by adjusting the relative phase of the bichromatic components. Our work offers a promising avenue for generating and modulating high-purity valley-polarized currents at the femtosecond timescale, facilitating the development of petahertz valleytronics. Copyright © 2024, The Authors. All rights reserved.

关键词： Landforms

来源：评论

学校读者我要写书评

暂无评论

Photoelectron ionization time of aligned molecules clocked by attosecond angular streaking

引用

Physical Review A 2020年第1期102卷 013117-013117页

作者： Jiaqing Yan Wenhai Xie Min Li Kun Liu Siqiang Luo Chuanpeng Cao keyu Guo Wei Cao Pengfei Lan Qingbin Zhang Yueming Zhou Peixiang Lu Wuhan National Laboratory for Optoelectronics and School of Physics Huazhong University of Science and Technology Wuhan 430074 China Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan 430205 China CAS Center for Excellence in Ultra-intense Laser Science Shanghai 201800 China

Attoclock is a powerful technique to resolve laser-driven electron dynamics on an attosecond time scale. Previously, it was mainly limited to atomic targets. Here we apply the attoclock technique to aligned molecules to study the subcycle ionization dynamics. By controlling the alignment of the molecule relative to the major axis of a strong elliptically polarized laser field, we demonstrate that the electron ionization time in aligned molecules can be precisely resolved by the attoclock technique. We find that the ionization time corresponding to the peak of the photoelectron momentum distribution shifts several tens of attoseconds relative to the laser field peak depending on the molecular orientation and molecular orbital structure. A significant difference between the measurement and molecular Ammosov-Delone-Krainov model is found. We further show that the photoelectron ionization time of molecules is sensitive to angular-dependent ionization rate, opening up opportunities for probing attosecond electron dynamics in complex polyatomic molecules.

关键词： Multiphoton or tunneling ionization & excitation Photoemission Ultrafast phenomena

来源：评论

学校读者我要写书评

暂无评论

Terahertz waves generation using the isomorphs of PPKTP crystal: A theoretical investigation

arXiv

引用

arXiv 2021年

作者： Chen, Guo-Qun Zhao, Hong-Yang Wang, Shun Hao, Xiangying Du, Hai-Wei Jin, Rui-Bo Hubei Key Laboratory of Optical Information and Pattern Recognition Department of Materials Science and Engineering Wuhan Institute of Technology Wuhan430205 China School of Measuring and Optical Engineering Nanchang Hangkong University Jiangxi Nanchang330063 China

Highly efficient terahertz (THz) wave sources based on difference frequency generation (DFG) process in nonlinear optical crystals play an important role for the applications of THz wave. In order to find more novel nonlinear crystals, here we theoretically investigate the generation of THz wave using the isomorphs of periodically poled KTiOPO4 (PPKTP), including periodically poled RTP, KTA, RTA and CTA. By solving the cascaded difference frequency coupled wave equations, it is found that the intensities of the THz wave generated from the cascaded difference frequency processes are improved by 5.27, 2.87, 2.82, 3.03, and 2.76 times from the non-cascaded cases for KTP, RTP, KTA, RTA and CTA, respectively. The effects of the crystal absorption, the phase mismatch and the pump intensity are also analyzed in detail. This study might help to provide a stronger THz radiation source based on the nonlinear crystals. © 2021, CC BY.

关键词： Terahertz waves

来源：评论

学校读者我要写书评

暂无评论

Quantum interferometers: Principles and applications

arXiv

引用

arXiv 2023年

作者： Jin, Rui-Bo Zeng, Zi-Qi You, Chenglong Yuan, Chenzhi Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology Wuhan430205 China Quantum Photonics Laboratory Department of Physics and Astronomy Louisiana State University Baton RougeLA United States

Interference, which refers to the phenomenon associated with the superposition of waves, has played a crucial role in the advancement of physics and finds a wide range of applications in physical and engineering measurements. Interferometers are experimental setups designed to observe and manipulate interference. With the development of technology, many quantum interferometers have been discovered and have become cornerstone tools in the field of quantum physics. Quantum interferometers not only explore the nature of the quantum world but also have extensive applications in quantum information technology, such as quantum communication, quantum computing, and quantum measurement. In this review, we analyze and summarize three typical quantum interferometers: the Hong-Ou-Mandel (HOM) interferometer, the N00N state interferometer, and the Franson interferometer. We focus on the principles and applications of these three interferometers. In the principles section, we present the theoretical models for these interferometers, including single-mode theory and multi-mode theory. In the applications section, we review the applications of these interferometers in quantum communication, computation, and measurement. We hope that this review article will promote the development of quantum interference in both fundamental science and practical engineering applications. © 2023, CC BY.

关键词： Quantum communication

来源：评论

学校读者我要写书评

暂无评论

Symmetry-enforced type-II Weyl phonons and hybrid Weyl nodal-line phonons in P4¯m2-carbon

引用

Physical Review B 2023年第23期108卷 235302-235302页

作者： Qing-Bo Liu Xiang-Feng Yang Zhe-Qi Wang Ziyang Yu Lun Xiong Hua-Hua Fu Hubei Key Laboratory of Optical Information and Pattern Recognition School of Optical Information and Energy Engineering School of Mathematics and Physics Wuhan Institute of Technology Wuhan 430073 China School of Physics and Wuhan National High Magnetic Field Center Huazhong University of Science and Technology Wuhan 430074 China Institute for Quantum Science and Engineering Huazhong University of Science and Technology Wuhan Hubei 430074 China

The exploration of unusual Weyl phonons has long been regarded as one of the central topics in topological physics. Our symmetry analysis shows that symmetry-enforced type-II Weyl phonons may exist under the protections from two mirror symmetries (Mx and My), a twofold rotation symmetry (C2z) and time-reversal symmetry (T), and meanwhile, another kind of unusual Weyl phonon, i.e., hybrid Weyl nodal-line phonons, may be constructed on a square and four straight Weyl nodal lines. Our first-principles calculations demonstrate that these two unusual Weyl phonons may coexist in a real material P4¯m2-carbon. More importantly, another kind of nontrivial surface states, i.e., which we refer to as hybrid surface states, are produced both by type-II Weyl phonons and by the hybrid Weyl nodal-line phonons. Our work provides an ideal material platform to study type-II Weyl phonons and hybrid Weyl nodal-line phonons in phononic systems.

关键词： Phonons Topological materials First-principles calculations

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：