检索结果-南通市图书馆

attosecond laser station

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2018年第7期27卷 50-65页

作者：滕浩贺新奎赵昆魏志义 Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences School of Physical Science University of Chinese Academy of Sciences

The attosecond laser station （ALS） at the Synergetic Extreme Condition User Facility （SECUF） is a sophisticated and user-friendly platform for the investigation of the electron dynamics in atoms, molecules, and condensed matter on timescales ranging from tens of femtoseconds to tens of attoseconds. Short and tunable coherent extreme-ultraviolet （XUV） light sources based on high-order harmonic generation in atomic gases are being developed to drive a variety of endstations for inspecting and controlling ultrafast electron dynamics in real time. The combination of such light sources and end-stations offers a route to investigate fundamental physical processes in atoms, molecules, and condensed matter. The ALS consists of four beamlines, each containing a light source designed specifically for application experiments that will be performed in its own end-station. The first beamline will produce broadband XUV light for attosecond photoelectron spectroscopy and attosecond transient absorption spectroscopy. It is also capable of performing attosecond streaking to characterize isolated attosecond pulses and will allow studies on the electron dynamics in atoms, moleculars, and condensed matter. The second XUV beamline will produce narrowband femtoseeond XUV pulses for time-resolved and angle-resolved photoelectron spectroscopy, to study the electronic dynamics on the timescale of fundamental correlations and interactions in solids, especially in superconductors and topological insulators. The third beamline will produce broadband XUV pulses for attosecond coincidence spectroscopy in a cold-target recoil-ion momentum spectrometer, to study the ultrafast dynamics and reactions in atomic and molecular systems. The last beamline produces broadband attosecond XUV pulses designed for time-resolved photoemission electron microscopy, to study the ultrafast dynamics of plasmons in nanostructures and the surfaces of solid materials with high temporal and spatial resolutions simultaneously. The main object of the ALS is to provide

关键词： attosecond extreme-ultraviolet （XUV） pulse pump-probe photoemission spectroscopy

All-optical attosecond time domain interferometry

在线全文

学校读者我要写书评

暂无评论

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

Quantum model simulations of attosecond electron diffraction

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2010年第6期53卷 987-1004页

作者： Peter BAUM Jrn MANZ Axel SCHILD Max-Planck-Institute of Quantum Optics and Ludwig-Maximilians-Universitt München Freie Universitt Berlin Institut für Chemie und Biochemie

Ultrafast diffraction with free attosecond electron pulses promises insight into the four-dimensional motion of charge density inatoms,molecules and condensed matter. Here we consider the quantum dynamics of the electron-electron scattering process on anattosecond time scale. By numerically solving the time-dependent two-electron Schrdinger equation,we investigate the interactionof an incoming keV-range electron wavepacket by the bound electron of an aligned H+2 molecule,using a one-dimensional model.Our findings reveal the ratio of elastic to inelastic contributions,the role of exchange interaction,and the influence of the molecularelectron density to diffraction. Momentum transfer during the scattering process,from the incoming to the bound electron mediatedby the nuclei,leaves the bound electron in a state of coherent oscillation with attosecond recurrences. Entanglement causes relatedstate-selective oscillations in the phase shift of the scattered electron. Two scenarios of distinguishable and indistinguishable freeand bound electrons yield equivalent results,irrespective of the electronic spins. This suggests to employ the scenario of distinguishable electrons,which is computationally less demanding. Our findings support the possibility of using electron diffraction forimaging the motion of charge density,but also suggest the application of free electron pulses for inducing attosecond dynamics.

关键词： ultrafast electron diffraction scattering theory attosecond dynamics entanglement coherence

attosecond twisted beams from high-order harmonicgeneration driven by optical vortices

在线全文

学校读者我要写书评

暂无评论

High Power Laser Science and Engineering 2017年第1期5卷 12-19页

作者： Carlos Hernandez-Garcia Laura Rego Julio San Roman Antonio Picon Luis Plaja Grupo de Investigacion en Aplicaciones del Laser y Fotonica Departamento de Fisica AplicadaUniversity of SalamancaE-37008SalamancaSpain Argonne National Laboratory Argonne1L 60439USA

Optical vortices are structures of the electromagnetic field with a spiral phase ramp about a point-phase singularity,carrying orbital angular momentum(OAM). Recently, OAM has been imprinted to short-wavelength radiation through high-order harmonic generation(HHG), leading to the emission of attosecond twisted beams in the extreme-ultraviolet(XUV) regime. We explore the details of the mapping of the driving vortex to its harmonic spectrum. In particular, we show that the geometry of the harmonic vortices is convoluted, arising from the superposition of the contribution from the short and long quantum paths responsible of HHG. Finally, we show how to take advantage of transverse phase-matching to select twisted attosecond beams with different spatiotemporal properties.

关键词： attosecond science extreme-ultraviolet vortices high harmonic generation orbital angular momentum twisted beams vortexbeams

Carrier Envelope Phase Description for an Isolated attosecond Pulse by Momentum Vortices

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2019年第6期36卷 24-28页

作者：李猛张贵忠丁欣姚键铨 College of Precision Instrument and Optoelectronics Engineering Tianjin University Civil Aviation Meteorological Institute Key Laboratory of Operation Programming & Safety Technology of Air Traffic Management Civil Aviation University of China

As a crucial parameter for a few-cycle laser pulse, the carrier envelope phase(CEP) substantially determines the laser waveform. We propose a method to directly describe the CEP of an isolated attosecond pulse(IAP) by the vortex-shaped momentum pattern, which is generated from the tunneling ionization of a hydrogen atom by a pair of time-delayed, oppositely and circularly polarized IAP-IR pulses. Superior to the angular streaking method that characterizes the CEP in terms of only one streak, our method describes the CEP of an IAP by the features of multiple streaks in the vortex pattern. The proposed method may open the possibility of capturing sub-cycle extreme ultraviolet dynamics.

关键词： Isolated attosecond Pulse Momentum Vortices carrier envelope phase(CEP)

Helicity of harmonic generation and attosecond polarization with bichromatic circularly polarized laser fields

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2019年第10期28卷 321-326页

作者：张军齐桐潘雪飞郭静朱凯光刘学深 College of Instrumentation and Electrical Engineering Jilin UniversityChangchun 130026China Institute of Atomic and Molecular Physics Jilin UniversityChangchun 130012China

We theoretically investigate the high-order harmonic generation(HHG) of helium atom driven by bichromatic counterrotating circularly polarized laser fields. By changing the intensity ratio of the two driving laser fields, the spectral chirality of the HHG can be controlled. As the intensity ratio increases, the spectral chirality will change from positive-to negativevalue around a large intensity ratio of the two driving fields when the total laser intensity keeps unchanged. However, the sign of the spectral chirality can be changed from positive to negative around a small intensity ratio of the two driving fields when the total laser intensity changes. At this time, we can effectively control the helicity of the harmonic spectrum and the polarization of the resulting attosecond pulses by adjusting the intensity ratio of the two driving laser fields. As the intensity ratio and the total intensity of the driving laser fields increase, the relative intensity of either the left-circularly or right-circularly polarized harmonic can be enhanced. The attosecond pulses can evolve from being elliptical to near linear correspondingly.

关键词： high-order harmonic generation bichromatic circularly polarized laser fields spectral chirality attosecond polarization

Controlling paths of high-order harmonic generation by orthogonal two-color fields

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2020年第4期29卷 242-245页

作者：马泽慧张彩萍马俊琳苗向阳 College of Physics and Information Engineering Shanxi Normal UniversityLinfen 041004China Key Laboratory of Spectral Measurement and Analysis of Shanxi Province Shanxi Normal UniversityLinfen 041004China

Controlling paths of high-order harmonic generation from H^2+ is theoretically investigated by numerically solving the time-dependent Schrodinger equation based on the Born-Oppenheimer approximation in orthogonal two-color fields.Our simulations show that the change of harmonic emission paths is dependent on time-dependent distribution of electrons.Compared with one-dimensional linearly polarized long wavelength laser,multiple returns are suppressed and short paths are dominant in the process of harmonic emission by two-dimensional orthogonal ω/2ω laser fields.Furthermore,not only are multiple returns weaken,but also the harmonic emission varies from twice to once in an optical cycle by orthogonalω/1.5ωlaser fields.Combining the time-frequency distributions and the time-dependent electron wave packets probability density,the mechanism of controlling paths is further explained.As a result,a 68-as isolated attosecond pulse is obtained by superposing a proper range of the harmonics.

关键词： high-order harmonic generation orthogonal two-color fields attosecond pulse generation

Ultra-high order harmonic generation via a free electron laser mechanism

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2010年第8期34卷 1140-1147页

作者：邓海啸戴志敏 Shanghai Institute of Applied Physics Chinese Academy of Sciences

In this paper, by using the ＂frequency up-conversion＂ principle with a high gain harmonic generation free electron laser and an external seed laser, we consider the possibility of modulating a relativistic electron beam on the attosecond scale, so that it can produce coherent spontaneous radiation from the deep ultraviolet to the hard X-ray spectral region with a very short radiator. Analytical estimation and three-dimensional numerical modeling show the great potential to reach ultra-high harmonics up to several thousand. For an electron bunch with the typical quality as in the free electron laser scheme and a seed laser with 800 nm wave- length, 0.8 nm attosecond trains with alterable duration and GW scale peak power are modeled. The output radiation exhibits good shot-to-shot stability, full coherence and perfect tuning ability between the discrete harmonics of the seed frequency.

关键词： FEL harmonic attosecond coherent

High harmonic generation and application for photoemission spectroscopy in condensed matter

在线全文

学校读者我要写书评

暂无评论

Materials Futures 2022年第3期1卷 53-67页

作者： Shiyang Zhong Yueying Liang Shuai Wang Hao Teng Xinkui He Zhiyi Wei Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190People’s Republic of China Songshan Lake Materials Laboratory Dongguan 523808People’s Republic of China University of Chinese Academy of Science Beijing 10049People’s Republic of China

High harmonic generation(HHG)delivering attosecond pulse duration with photon energy in the extreme ultraviolet spectral range has been demonstrated as a robust table-top coherent light source,allowing for the observation and manipulation of ultrafast process within the shortest time window ever made by humans.The past decade has witnessed the rapid progress of HHG from a variety of solid targets and its application for photoemission spectroscopy in condensed matter.In this article,we review the HHG in solids and the understanding of the underlying physics of HHG,which allows all-optical band structure reconstruction.We also introduce combinations of HHG source and photoemission spectroscopy,such as angular-resolved photoemission spectroscopy and photoemission electron microscopy.With the capacity of exploring a wide momentum space and high temporal resolution,the extension of attosecond science to the field of condensed matter physics will lead to new insights into the fundamental ultrafast dynamics in novel quantum materials.

关键词： high harmonic generation attosecond angle-resolved photoemission spectroscopy ultrafast dynamics photoemission electron microscopy