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Attosecond probing and control of charge migration in carbon-chain molecule

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Advanced Photonics 2023年第5期5卷 33-40页

作者： Lixin He Yanqing He Siqi Sun Esteban Goetz Anh-Thu Le Xiaosong Zhu Pengfei Lan peixiang lu Chii-Dong Lin Huazhong University of Science and Technology Wuhan National Laboratory for Optoelectronics and School of PhysicsWuhanChina University of Connecticut Department of PhysicsStorrsConnecticutUnited States Wuhan Institute of Technology Hubei Key Laboratory of Optical Information and Pattern RecognitionWuhanChina Kansas State University Department of PhysicsManhattanKansasUnited States

In quantum mechanics,when an electron is quickly ripped off from a molecule,a superposition of new eigenstates of the cation creates an electron wave packet that governs the charge flow inside,which has been called charge migration(CM).Experimentally,extracting such dynamics at its natural(attosecond)timescale is quite difficult.We report the first such experiment in a linear carbon-chain molecule,butadiyne(C_(4)H_(2)),via high-harmonic spectroscopy(HHS).By employing advanced theoretical and computational tools,we showed that the wave packet and the CM of a single molecule are reconstructed from the harmonic spectra for each fixed-in-space angle of the molecule.For this onedimensional molecule,we calculate the center of charge (t) to obtain v_(cm),to quantify the migration speed and how it depends on the orientation angle.The findings also uncover how the electron dynamics at the first few tens to hundreds of attoseconds depends on molecular structure.The method can be extended to other molecules where the HHS technique can be employed.

关键词： attosecond charge migration high-harmonic spectroscopy single-molecule harmonic dipole machine learning

Probing the launching position of the electron wave packet in molecule strong-field tunneling ionization

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Science China(Physics,Mechanics & Astronomy) 2021年第7期64卷 82-90页

作者： Yueming Zhou Jia Tan Min Li peixiang lu School of Physics and Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan430074China Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of TechnologyWuhan430205China

Strong-field tunneling ionization is the first step for a broad class of phenomena in intense laser-atom/molecule interactions. Accurate information about the electron wave packet from strong-field tunneling ionization of atoms and molecules is of essential importance for understanding various tunneling ionization triggered processes. Here, we survey the property of the electron wave packet in tunneling ionization of molecules with a method based on strong-field photoelectron holography. By solving the time-dependent Schr ¨odinger equation, it is shown that the holographic interference in the photoelectron momentum distribution exhibits the asymmetric behavior with respect to the laser polarization direction, when the molecule is aligned with a nonzero angle to the linearly polarized laser field. We demonstrate that this asymmetry is due to the nonzero initial transverse displacement of the electron wave packet at tunneling. By analyzing the holographic interference, this transverse displacement for the launching of electron wave packet tunneling from the molecules is accurately retrieved. This displacement is directly related to the electron density distribution in molecules, and thus our work developed a novel concept for probing electronic structure in molecules.

关键词： strong-field tunneling ionization photoelectron holography attosecond dynamics

Corrosion and Fatigue Testing of Microsized 304 Stainless Steel Beams Fabricated by Femtosecond Laser

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Journal of Materials Science & Technology 2009年第2期25卷 187-193页

作者： Qiang Zhang Xingpeng Guo Nengli Dai peixiang lu Department of Chemistry and Chemical Engineering Huazhong University of Science and Technology Wuhan 430074 China Wuhan National Laboratory for Optoelectronics and School of Optoelectronics Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China

The 304 stainless steel （SS） microcantilever specimens with dimensions of 30 #m ×30 #m ×50 #m （thicknessx width × length） were fabricated by femtosecond （fs） laser. The microsized cantilevers of good quality with structure and dimensions according commendably with that of the designed cantilever were obtained. The result shows that fs laser micromachining is a promising method for directly fabricating metallic microcomponents. Corrosion and fatigue properties of microsized specimens were carried out on the microsized 304 SS cantilever beams by a newly developed fatigue testing machine. The results show that the microsized 304 SS specimens appear to have an improved resistance towards localized corrosion compared to ordinary-sized 304 SS specimens after the static corrosion testing. The testing result shows that the presence of corrosive solution reduces the fatigue lifetime of the 304 SS specimen by a factor of 10-100. The maximum bending loads measured by fatigue testing machine decrease rapidly at the terminal stage of environment assisted fatigue testing. Corrosion fracture first occurred at the range of notch with a higher tensile bending stress, and exhibited clear evidence of trans-columnar fracture detected by SEM （scanning electron microscopy）.

关键词： Corrosion fatigue Stainless steel Femtosecond laser Microsystem

All-optical attosecond time domain interferometry

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National Science Review 2021年第10期8卷 15-22页

作者： Zhen Yang Wei Cao Yunlong Mo Huiyao Xu Kang Mi Pengfei Lan Qingbin Zhang peixiang lu Wuhan National Laboratory for Optoelectronics and School of Physics Huazhong University of Science and Technology Hubei Key Laboratory of Optical Information and Pattern Recognition Wuhan Institute of Technology CAS Center for Excellence in Ultra-intense Laser Science

Interferometry, a key technique in modern precision measurements, has been used for length measurement in engineering metrology and astronomy. An analogous time-domain interferometric technique would represent a significant complement to spatial domain applications and require the manipulation of interference on extreme time and energy scales. Here, we report an all-optical interferometer using laser-driven high order harmonics as attosecond temporal slits. By controlling the phase of the temporal slits with an external field, a time domain interferometer that preserves both attosecond temporal resolution and hundreds of me V energy resolution is implemented. We apply this exceptional temporal resolution to reconstruct the waveform of an arbitrarily polarized optical pulse, and utilize the provided energy resolution to interrogate the abnormal character of the transition dipole near the Cooper minimum in argon. This novel attosecond interferometry paves the way for high precision measurements in the time-energy domain using all-optical approaches.

关键词： interferometry attosecond all-optical precision measurement

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高平均功率高次谐波光源的研究进展(特邀)

光子学报 2024年第6期53卷 13-25页

作者：孟黎辉兰鹏飞陆培祥华中科技大学武汉光电国家研究中心物理学院武汉430074

阿秒激光脉冲(10-18 s)具有超高的时间分辨率,可以用于实现原子分子内的电子动力学的探测,这使阿秒科学成为超快光学领域里最受关注的研究前沿。传统的钛宝石飞秒激光驱动的高次谐波阿秒脉冲平均功率较低。最近,高平均功率的掺镱激光发... 详细信息

阿秒激光脉冲(10-18 s)具有超高的时间分辨率,可以用于实现原子分子内的电子动力学的探测,这使阿秒科学成为超快光学领域里最受关注的研究前沿。传统的钛宝石飞秒激光驱动的高次谐波阿秒脉冲平均功率较低。最近,高平均功率的掺镱激光发展迅速,为产生高功率高次谐波阿秒脉冲提供了良好的驱动源。本文回顾了近二十年高重频的高次谐波光源的平均功率和最高光子能量逐步提高的研究进展,并介绍了高重频高次谐波阿秒脉冲在泵浦探测实验和相干成像等方面的应用和前景。

关键词：高次谐波阿秒脉冲高平均功率极紫外掺镱激光器

Full experimental determination of tunneling time with attosecond-scale streaking method

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Light(Science & Applications) 2022年第8期11卷 1903-1908页

作者： Miao Yu Kun Liu Min Li Jiaqing Yan Chuanpeng Cao Jia Tan Jintai Liang 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 Technology430074WuhanChina Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application School of Physical Science and TechnologySuzhou University of Science and Technology215009SuzhouChina Optics Valley Laboratory 430074HubeiChina

Tunneling is one of the most fundamental and ubiquitous processes in the quantum world.The question of how long a particle takes to tunnel through a potential barrier has sparked a long-standing debate since the early days of quantum mechanics.Here,we propose and demonstrate a novel scheme to accurately determine the tunneling time of an electron.In this scheme,a weak laser field is used to streak the tunneling current produced by a strong elliptically polarized laser field in an attoclock configuration,allowing us to retrieve the tunneling ionization time relative to the field maximum with a precision of a few attoseconds.This overcomes the difficulties in previous attoclock measurements wherein the Coulomb effect on the photoelectron momentum distribution has to be removed with theoretical models and it requires accurate information of the driving laser fields.We demonstrate that the tunneling time of an electron from an atom is close to zero within our experimental accuracy.Our study represents a straightforward approach toward attosecond time-resolved imaging of electron motion in atoms and molecules.

关键词： tunneling quantum scheme

Real-time observation of frequency Bloch oscillations with fibre loop modulation

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Light(Science & Applications) 2021年第3期10卷 434-442页

作者： Hao Chen NingNing Yang Chengzhi Qin Wenwan Li Bing Wang Tianwen Han Chi Zhang Weiwei Liu Kai Wang Hua Long Xinliang Zhang peixiang lu School of Physics and Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China

Bloch oscillations(BOs)were initially predicted for electrons in a solid lattice to which a static electric field is applied.The observation of BOs in solids remains challenging due to the collision scattering and barrier tunnelling of electrons.Nevertheless,analogies of electron BOs for photons,acoustic phonons and cold atoms have been experimentally demonstrated in various lattice systems.Recently,BOs in the frequency dimension have been proposed and studied by using an optical micro-resonator,which provides a unique approach to controlling the light frequency.However,the finite resonator lifetime and intrinsic loss hinder the effect from being observed practically.Here,we experimentally demonstrate BOs in a synthetic frequency lattice by employing a fibre-loop circuit with detuned phase modulation.We show that a detuning between the modulation period and the fibre-loop roundtrip time acts as an effective vector potential and hence a constant effective force that can yield BOs in the modulation-induced frequency lattices.With a dispersive Fourier transformation,the pulse spectrum can be mapped into the time dimension,and its transient evolution can be precisely measured.This study offers a promising approach to realising BOs in synthetic dimensions and may find applications in frequency manipulations in optical fibre communication systems.

关键词： fibre Bloch dimension

Direct Visualization of Deforming Atomic Wavefunction in Ultraintense High-Frequency Laser Pulses

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Ultrafast Science 2022年第5期2卷 13-20页

作者： Jintai Liang Yueming Zhou Yijie Liao Wei-Chao Jiang Min Li peixiang lu School of Physics and Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Optics Valley Laboratory Hubei 430074China

Interaction of intense laser fields with atoms distorts the bound-state electron cloud.Tracing the temporal response of the electron cloud to the laser field is of fundamental importance for understanding the ultrafast dynamics of various nonlinear phenomena of matter,but it is particularly challenging.Here,we show that the ultrafast response of the atomic electron cloud to the intense high-frequency laser pulses can be probed with the attosecond time-resolved photoelectron holography.In this method,an infrared laser pulse is employed to trigger tunneling ionization of the deforming atom.The shape of the deforming electron cloud is encoded in the hologram of the photoelectron momentum distribution.As a demonstration,by solving the time-dependent Schrödinger equation,we show that the adiabatic deforming of the bound-state electron cloud,as well as the nonadiabatic transition among the distorted states,is successfully tracked with attosecond resolution.Our work films the formation process of the metastable Kramers-Henneberger states in the intense high-frequency laser pulses.This establishes a novel approach for time-resolved imaging of the ultrafast bound-state electron processes in intense laser fields.

关键词： intense photoelectron resolved

高重复频率、高功率高次谐波极紫外光源进展及应用

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中国激光 2024年第7期51卷 3-21页

作者：魏子娟高熙泽孟翔宇李政言张庆斌兰鹏飞陆培祥华中科技大学光学与电子信息学院湖北武汉430074 华中科技大学物理学院湖北武汉430074 华中科技大学武汉光电国家研究中心湖北武汉430074 湖北光谷实验室湖北武汉430074

超短超强激光脉冲驱动的高次谐波是一种极紫外到软X射线波段的光源,具有指向性好、时空相干性高、亮度高等优点。高次谐波不但是在阿秒时间尺度上研究电子动力学的基础,而且其各类技术优点也使之成为一种有效的桌面型极紫外相干光源,在... 详细信息

超短超强激光脉冲驱动的高次谐波是一种极紫外到软X射线波段的光源,具有指向性好、时空相干性高、亮度高等优点。高次谐波不但是在阿秒时间尺度上研究电子动力学的基础,而且其各类技术优点也使之成为一种有效的桌面型极紫外相干光源,在集成电路制造在线检测、材料科学、生物医药等领域中具有广泛应用。然而,受限于传统钛蓝宝石固体飞秒激光的平均功率和高次谐波传播过程中的转换效率,目前高次谐波极紫外光源的平均功率亟待提高。介绍了高重复频率、高平均功率高次谐波极紫外光源的产生方式及其应用。首先介绍了光纤、固体、啁啾光学参量放大器等新型高重复频率、高平均功率飞秒激光驱动源在高次谐波产生方面的研究进展,之后讨论了激光高次谐波在弱电离气体介质中的宏观传播效应和相位匹配条件。在此基础上,介绍了高平均功率高次谐波极紫外光源在成像检测方面的应用。

关键词：非线性光学高次谐波极紫外光源飞秒激光器极紫外成像检测