A5025625584- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Laser-Matter Interactions and Applications
- High-pressure geophysics and materials
- Atomic and Molecular Physics
- Magnetic confinement fusion research
- Dust and Plasma Wave Phenomena
- Advanced Fiber Laser Technologies
- Nuclear Physics and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Ionosphere and magnetosphere dynamics
- Particle Dynamics in Fluid Flows
- Quantum Dots Synthesis And Properties
- Quantum, superfluid, helium dynamics
- Gyrotron and Vacuum Electronics Research
- Advanced X-ray Imaging Techniques
- Particle Accelerators and Free-Electron Lasers
- Advanced Electron Microscopy Techniques and Applications
- Terahertz technology and applications
- Ion-surface interactions and analysis
- Gamma-ray bursts and supernovae
- Parallel Computing and Optimization Techniques
- Fluid Dynamics and Turbulent Flows
- Pulsed Power Technology Applications
- Electron and X-Ray Spectroscopy Techniques
Shenzhen Technology University
2021-2025
Institute of Applied Physics and Computational Mathematics
2015-2024
National University of Defense Technology
1998-2024
Shanghai Jiao Tong University
2010-2023
Peking University
2014-2023
State Key Laboratory of Nuclear Physics and Technology
2020-2023
Laser Fusion Research Center
2010-2021
Ministry of Education of the People's Republic of China
2017-2019
China Academy of Engineering Physics
2010-2018
Beijing Institute of Technology
2018
PbS quantum dots (QDs) are promising materials for low-cost short-wave infrared (SWIR) photodetection and imaging applications, owing to their unique optical properties tunable bandgap. High-performance photodiodes rely on thiol-treated small QDs as the hole transport layer (HTL) due suitable band alignment, but they face challenges such crack formation, which increases dark currents. We develop a crack-free HTL by mixing small-size large-size QDs. Grazing incidence small-angle X-ray...
Two-dimensional particle-in-cell simulation shows that a target with subwavelength nanolayered front can reduce the reflection and increase absorption of energy an intense short laser pulse. The electrons within skin depth on surfaces nanolayers are accelerated by J×B heating to relativistic velocities ejected into narrow vacuum spaces between layers. They then propagate forward most absorbed along Conversion electron be enhanced optimizing spacing since phase structure field in is modified....
Laser interaction with a nanobrush target plasma is investigated at the SILEX-I laser facility [X. F. Wei et al., J. Phys. Conf. Ser. 112, 032010 (2008)] of intensity 7.9×1018 W/cm2. Highly collimated fast electron beams yields more than three times higher that from planar can be produced. Two-dimensional particle-in-cell simulation confirms layered surface structure increase efficiency energy absorption, and resulting electrons are tightly guided by layers to cross section about spot size.
By irradiating a flat Al target with femtosecond laser pulses at moderate intensities of $\ensuremath{\sim}{10}^{17}\text{ }\text{ }\mathrm{W}/{\mathrm{cm}}^{2}$, we obtained stable collimated quasimonoenergetic electrons in the specular direction but deviated somewhat toward normal. An associated local minimum located on other side seems to indicate that peak actually results from deflection their initial ejection direction. We have proposed two-step model which some laser-accelerated are...
Hot electrons generated by short-pulse-laser interaction with nanolayered target (NT) are investigated using two-dimensional particle-in-cell simulation. Compared to the planar target, NT leads more efficient conversion of laser energy kinetic accelerated electrons. However, absorption decreases at both too-low and too-high intensities. At lower intensities it is because weaker electric magnetic fields hot-electron jets smaller relativistic skin depth. higher damage or destruction layered...
The propagation of light waves in an underdense plasma is studied using one-dimensional Vlasov–Maxwell numerical simulation. It found that the backward stimulated Raman scattering will be enhanced by electron-ion collisions. With appropriate collision rate Langmuir waves, driven via SRS, can made to propagate for a long distance.
By using a millijoule kHz femtosecond laser pulse to irradiate preformed expanding spherical plasma, which is driven by prepulse with intensity of $1\ifmmode\times\else\texttimes\fi{}{10}^{14}\text{ }\text{ }\mathrm{W}/{\mathrm{cm}}^{2}$, we observe fast-electron-mediated filamentary structures and an accompanying self-organized magnetic-tube array 2000 T via time-resolved magneto-optical polarization rotation measurements. We reveal that these periodical predominantly originate from ejected...
This study proposes a novel method to mitigate stimulated Brillouin scattering (SBS) using multicolor alternating-polarization bundle light. The light combines multiwavelength, spike trains of uneven duration and delay for single beam alternating polarization beams. SBS suppression is verified three-dimensional large-scale laser plasma code. numerical results show that the reflectivity can be decreased by nearly two orders in low density plasma. proposed extend repetition time from several...
Using conventional methods, a laser pulse can be focused down to around $6--8\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{m}$, but further reduction of the spot size has proven difficult. Here it is shown by particle-in-cell simulation that with hollow cone an intense reduced tiny, highly localized, $1\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{m}$ radius, accompanied much enhanced light intensity. The shaping and focusing effect due nonlinear laser-plasma interaction on inner...
PbS quantum dots (QDs) are promising for short-wave infrared (SWIR) photodetection and imaging. Solid-state ligand exchange (SSLE) is a low-fabrication-threshold QD solid fabrication method. However, treatment by SSLE remains challenging in seeking refined surface passivation to achieve the desired device performance. This work investigates using NaAc process enhance film morphology electronic coupling configuration of solids. By implementing various photodetector characterization studies,...
Laser plasma interactions in a relativistic regime relevant to the fast ignition inertial confinement fusion have been investigated. Ultraintense laser propagation preformed plasmas and hot electron generation are studied. The experiments performed using 100 TW 0.6 ps 20 synchronized by long pulse laser. In study, self-focused ultraintense beam propagates along its axis into an overdense with peak density 1022/cm3. Channel formation is observed. transmission depends on position of focus can...
A new method to reduce the scattering levels of stimulated Raman (SRS) and Brillouin (SBS) is proposed using alternating-polarization light. The effect technique related alternating time. If time smaller than growth time, level SRS or SBS can be decreased. process simulated by fluid method, verified particle-in-cell method. This also compared with spike trains uneven duration delay (STUD) technique. Combining STUD pulses light discussed. Under proper parameters, dramatically reduced more one...
Abstract The rescattering of backward stimulated Raman scattering (BSRS) by Brillouin (SBS) is found in the high electron density region relativistic Vlasov-Maxwell simulation and particle-in-cell (PIC) simulation, where BSRS regime absolute instability dominates all scatterings. Both one dimension (1D) Vlasov two (2D) PIC have been given to verify that there exists SBS for BSRS. will be even stronger than forward (FSRS) Thus, besides Langmuir decay laser energy absorption, also an important...
Electron acceleration from the interaction of an intense short-pulse laser with low density plasma is considered. The relation between direct electron within pulse and that in wake investigated analytically. magnitude location ponderomotive-force-caused charge separation field respect to determine relative effectiveness two mechanisms. It shown there optimum condition for wake. dominates as becomes sufficiently short, latter directly drives even traps electrons. can reach ultrahigh energies...
The properties of the nonlinear frequency shift (NFS), especially fluid NFS from harmonic generation ion-acoustic wave (IAW) in multi-ion species plasmas, have been researched by Vlasov simulation. Pictures and particle trapping are shown to explain mechanism qualitatively. theoretical model plasmas is given, results simulation consistent with result plasmas. When number kλ_{De} small, such as kλ_{De}=0.1, dominates total will reach large nearly 15% when amplitude |eϕ/T_{e}|∼0.1, which...
Abstract Channeling by a train of laser pulses into homogeneous and inhomogeneous plasmas is studied using particle-in-cell simulation. When the pulse duration interval between successive are appropriate, can channel plasma deeper than single long-pulse similar peak intensity total energy. The increased penetration distance be attributed to repeated actions ponderomotive force, continuous between-pulse lengthening inertially evacuating ions, suppression laser-driven instabilities...
Abstract A scheme capable of enhancing the energy monoenergetic protons in high intensity laser-plasma interactions is proposed and demonstrated by two dimensional particle-in-cell simulations. The focusing laser light pulse guiding surface current via Z material cone-shaped substrate increase temperature hot electrons, which are responsible for electrostatic field accelerating protons. Moreover, sub-micron proton layer coated on makes total beam experience same field, thus monochromaticity...
The Monte Carlo transport code Geant4 has been used to study positron production in the of laser-produced hot electrons solid targets. dependence yield on target parameters and hot-electron temperature investigated thick targets (mm-scale), where only Bethe-Heitler process is considered. results show that Au best material, an optimal thickness exists for generating abundant positrons at a given temperature. angular distributions energy spectra different electron temperatures were studied...
A conical nanobrush target is proposed to improve the total proton energy-conversion efficiency in beam acceleration and investigated by two-dimensional particle-in-cell (2D-PIC) simulations. Results indicate a significant enhancement of number energies hot electrons through rear side target. Compared with plain target, field increases several times. We observe enhancements average energy laser-proton conversion 105%. This attributed both configurations. The well collimated divergence angle...
To improve the energy coupling efficiency from laser to forward hot electrons, we propose a conical nanolayered target (CNT) and investigate by two-dimensional particle-in-cell simulations. Compared with target, is enhanced 34% more than 68%. Detailed simulations indicate that this enhancement attributed both oblique incidence focusing of target. Moreover, CNT collimates electrons better. The proposed may serve as new method for enhancing efficiency.
An ultraintense femtosecond laser pulse was used, for the first time, to produce a strong magnetic field with controlled shapes by interactions capacitor-coil target high efficiency. The temporal evolution of obtained time-gated proton radiography method. A comparison high-resolution radiographic images deflection and particle-track simulations indicates peak ∼20 T. energy conversion efficiency from is as ∼10%. simple model laser-driven gives relationship between strength electron...
Measurements of the ion emission from targets irradiated with neodymium glass and iodine lasers were analyzed a very significant anomaly observed. The fastest ions high charge number Z , which usually are megaelectron volt energy following relativistic self-focusing nonlinear-force acceleration theory, reduced to less than 50 times lower energies when 1.2 ps laser pulses about 1 J incident. We clarify this discrepancy by model skin depth plasma front interaction in contrast filament...