A5074098778- Laser-Plasma Interactions and Diagnostics
- Laser-Matter Interactions and Applications
- Laser-induced spectroscopy and plasma
- Particle Accelerators and Free-Electron Lasers
- Advanced X-ray Imaging Techniques
- Particle accelerators and beam dynamics
- Gyrotron and Vacuum Electronics Research
- Laser Design and Applications
- High-pressure geophysics and materials
- Terahertz technology and applications
- Advanced X-ray and CT Imaging
- Atomic and Molecular Physics
- Ion-surface interactions and analysis
- Pulsed Power Technology Applications
- Crystallography and Radiation Phenomena
- Plasma Diagnostics and Applications
- Medical Imaging Techniques and Applications
- Advanced Fiber Laser Technologies
- Radiation Therapy and Dosimetry
- Laser Material Processing Techniques
- Magnetic confinement fusion research
- Photonic and Optical Devices
- Advanced Electron Microscopy Techniques and Applications
- Laser and Thermal Forming Techniques
- Photocathodes and Microchannel Plates
Tsinghua University
2016-2025
China University of Geosciences (Beijing)
2025
University of Electronic Science and Technology of China
2024
National Central University
2021
University of California, Los Angeles
2021
National Taiwan University
2021
Institute of Atomic and Molecular Sciences, Academia Sinica
2021
China Academy of Engineering Physics
2007-2020
Ministry of Education of the People's Republic of China
2013
Key Laboratory of Nuclear Radiation and Nuclear Energy Technology
2010
The production of ultrabright electron bunches using ionization injection triggered by two transversely colliding laser pulses inside a beam-driven plasma wake is examined via three-dimensional particle-in-cell simulations. relatively low intensity lasers are polarized along the axis and overlap with for very short time. result that residual momentum ionized electrons in transverse plane reduced, localized propagation wake. This minimizes both initial thermal emittance growth due to phase...
Tsinghua Thomson Scattering X-ray Source (TTX) is the first-of-its-kind dedicated hard source in China based on scattering between a terawatt ultrashort laser and relativistic electron beams. In this paper, we report experimental generation characterization of first pulses (51.7 keV) via head-on collision an 800 nm 46.7 MeV The measured yield 1.0 × 106 per pulse with bunch charge 200 pC energy 300 mJ. angular intensity distribution spectra are electron-multiplying charge-coupled device using...
Phase space matching between two plasma-based accelerator (PBA) stages and a PBA traditional component is critical issue for emittance preservation. The drastic differences of the transverse focusing strengths as beam propagates components may lead to catastrophic growth even when there small energy spread. We propose using linear forces from nonlinear wakes in longitudinally tailored plasma density profiles control phase sections with negligible growth. Several are considered theoretical...
The evolution of beam phase space in ionization injection into plasma wakefields is studied using theory and particle-in-cell simulations. process involves both longitudinal transverse mixing, leading initially to a rapid emittance growth followed by oscillation, decay, slow saturation. An analytic for this presented verified through This includes the effects distance (time), acceleration distance, wakefield structure, nonlinear charge forces, it also shows how ultralow beams can be produced methods.
Ionization injection triggered by short wavelength laser pulses inside a nonlinear wakefield driven longer is examined via multidimensional particle-in-cell simulations. We find that very bright electron beams can be generated through this two-color scheme in either collinear propagating or transverse colliding geometry. For fixed intensity $I$, lasers with longer/shorter $\ensuremath{\lambda}$ have larger/smaller ponderomotive potential ($\ensuremath{\propto}I{\ensuremath{\lambda}}^{2}$)....
We show that a high-energy electron bunch can be used to capture the instantaneous longitudinal and transverse field structures of highly transient, microscopic, laser-excited relativistic wake with femtosecond resolution. The spatiotemporal evolution wakefields in plasma density up ramp is measured reversal wake, where wavelength at particular point space increases until disappears completely only reappear later time but propagating opposite direction, observed for first by using this new technique.
Plasma-based accelerators have made impressive progress in recent years. However, the beam energy spread obtained these is still at ~ 1 % level, nearly one order of magnitude larger than what needed for challenging applications like coherent light sources or colliders. In plasma accelerators, mainly dominated by its chirp (longitudinally correlated spread). Here we demonstrate that when an initially chirped electron from a linac with proper current profile sent through low-density structure,...
Plasma wakefield acceleration in the blowout regime is particularly promising for high-energy of electron beams because its potential to simultaneously provide large gradients and high energy transfer efficiency while maintaining excellent beam quality. However, no equivalent positron plasma wakes has been discovered date. We show that after a short propagation distance, an asymmetric drives stable hollow channel can be both accelerating focusing beam. A charge bunch placed at suitable...
We have demonstrated single-shot continuously time-resolved MeV ultrafast electron diffraction using a static single crystal gold sample. An high density pulse was used to probe the sample and then streaked by an rf deflecting cavity. The single-shot, quality, pattern allowed structural information within several picoseconds be temporally resolved with ∼200 fs resolution. temporal resolution can straightforwardly improved 100 increasing streaking strength. foresee that this system would...
With progress of photoinjector technology, thermal emittance has become the primary limitation electron beam brightness. Extensive efforts have been devoted to study emittance, but experiment results differ between research groups and few can be well interpreted. Besides ambiguity photoemission mechanism, variations cathode surface conditions during preparation, such as work function, field enhancement factor, roughness, will cause differences. In this paper, we report an experimental...
Abstract Availability of relativistically intense, single-cycle, tunable infrared sources will open up new areas relativistic nonlinear optics plasmas, impulse IR spectroscopy and pump-probe experiments in the molecular fingerprint region. However, generation such pulses is still a challenge by current methods. Recently, it has been proposed that time dependent refractive index associated with laser-produced wakes suitably designed plasma density structure rapidly frequency down-converts...
Polarized x-ray source is a useful probe for many fields, such as fluorescence imaging, magnetic microscopy, and nuclear physics research. All-optical inverse Compton scattering (AOCS) based on laser wakefield accelerator (LWFA) has drawn great attention in recent years due to its compact scale high performance, especially potential generate polarized x rays. Here, polarization-tunable AOCS rays are generated by plasma-mirror-based scheme. The linearly circularly measured have the mean...
The transverse stability of the target is crucial for obtaining high quality ion beams using laser radiation pressure acceleration (RPA) mechanism. In this Letter, a theoretical model and supporting two-dimensional (2D) particle-in-cell (PIC) simulations are presented to clarify physical mechanism instability observed in RPA process. It shown that density ripples foil mainly induced by coupling between oscillating electrons quasistatic ions, similar two stream inertial confinement fusion...
A new method capable of capturing coherent electric field structures propagating at nearly the speed light in plasma with a time resolution as small few femtoseconds is proposed. This uses long relativistic electron bunch to probe wake produced by an intense laser pulse or ultra-short charged particle beam. As traverses wake, its momentum modulated leading density variation after free-space propagation. produces snapshot that can directly give many useful information structure and evolution....
To help the blind or visually impaired (BVI) read digitally conveniently and at low cost, we propose a bounce-type actuator driven by electromagnetic force, based on this, refreshable Braille display (RBD) which can both tactile graphic information is manufactured. The internal components of include an electromagnet two permanent magnets placed in stepped manner. By passing current different directions to coil, bounce up down between under action magnetic thereby achieving changes raised...
Abstract This paper provides an overview of the current status ultrafast and ultra-intense lasers with peak powers exceeding 100 TW examines research activities in high-energy-density physics within China. Currently, 10 high-intensity over are operational, about additional being constructed at various institutes universities. These facilities operate either independently or combined one another, thereby offering substantial support for both Chinese international development efforts physics.
The temporal evolution of the magnetic field associated with electron thermal Weibel instability in optical-field ionized plasmas is measured using ultrashort (1.8 ps), relativistic (45 MeV) bunches from a linear accelerator. self-generated fields are found to self-organize into quasistatic structure consistent helicoid topology within few picoseconds and such lasts for tens underdense plasmas. growth rate agrees well that predicted by kinetic theory taking account collisions. Magnetic...
Phase-contrast imaging using X-ray sources with high spatial coherence is an emerging tool in biology and material science. Much of this research being done large synchrotron facilities or relatively low-flux microfocus tubes. An alternative high-flux, ultra-short high-spatial-coherence table-top source based on betatron motions electrons laser wakefield accelerators has the promise to produce quality images. In previous phase-contrast studies sources, single-exposure images a resolution...
We demonstrate a highly efficient method for the generation of high-field terahertz (THz) pulse train via optical rectification (OR) in congruent lithium niobate (LN) crystals driven by temporally shaped laser pulses. A narrowband THz has been successfully achieved with sub-percent level conversion efficiency and multi MV/cm peak field at 0.26 THz. For single-cycle generation, we 373- μ J energy LN crystal excited 100-mJ room temperature. The is further improved to 0.77 % pumped 20-mJ...