A5010332732- Particle Accelerators and Free-Electron Lasers
- Advanced X-ray Imaging Techniques
- Particle accelerators and beam dynamics
- Laser-Plasma Interactions and Diagnostics
- Crystallography and Radiation Phenomena
- Orbital Angular Momentum in Optics
- Superconducting Materials and Applications
- Terahertz technology and applications
- Gyrotron and Vacuum Electronics Research
- Antenna Design and Analysis
- Radio Astronomy Observations and Technology
- Laser-Matter Interactions and Applications
- Advanced Electron Microscopy Techniques and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Antenna Design and Optimization
- X-ray Spectroscopy and Fluorescence Analysis
- Adrenal and Paraganglionic Tumors
- Spectroscopy and Laser Applications
- Mechanical and Optical Resonators
- Photonic and Optical Devices
Shanghai Zhangjiang Laboratory
2023-2024
Chinese Academy of Sciences
2009-2023
University of Chinese Academy of Sciences
2019-2023
Shanghai Institute of Applied Physics
2019-2021
Abstract The cavity-based X-ray free-electron laser (XFEL) has promise in producing fully coherent pulses with a bandwidth of few meV and very stable intensity, whereas the currently existing self-amplified spontaneous emission (SASE) XFEL is capable generating ultra-short chaotic spectra. In general, can provide spectral brightness three orders magnitude higher than that SASE mode, thereby opening new door for cutting-edge scientific research. With development superconducting MHz...
The Shanghai High repetition rate XFEL and Extreme light facility (SHINE) is under construction aims at generating X-rays between 0.4 25 keV with three FEL beamlines rates of up to 1 MHz. soft X-ray beamline, FEL-II, will be ready for commissioning in 2025. It designed cover the photon energy from 3 keV, which baselines operation modes are self-amplified spontaneous emission (SASE), self-seeding, echo-enabled harmonic generation (EEHG), polarization control. Therefore, a high repetition-rate...
The generation of light beams carrying orbital angular momentum (OAM) from a free-electron laser at short wavelengths has attracted considerable attention as key resource in several fields and applications. Herein, we present facile method to generate intense coherent OAM an X-ray oscillator (XFELO). We use the Bragg crystal both reflector well mode selector, longitudinal transverse modes, which enables specified resonance deviation that maximizes single-pass gain high-order interest. This...
X-ray vortices carrying tunable orbital angular momentum (OAM) are an emerging tool for x-ray characterization. However, in contrast to the generation of vortex beams visible wavelength region, a controlled manner has proved challenging. Here, we demonstrate free-electron laser oscillator (XFELO) can adjust only kinetic energy electron beam produce that be programmed dynamically change between different OAM modes, without need additional optical elements. With nominal parameters currently...
As a new-generation light source, free-electron lasers (FELs) provide high-brightness X-ray pulses at the angstrom-femtosecond space and time scales. The fundamental physics behind FEL is interaction between an electromagnetic wave relativistic electron beam in undulator, which consists of hundreds or thousands dipole magnets with alternating magnetic field. Here, we report first observation laser-beam pure magnet, energy modulation 40-keV amplitude 266-nm period measured. We demonstrate...
High-intensity, fully coherent x-ray pulse with a tunable polarization over wide spectral range is of great importance to many experiments. In this paper, we propose tapered crossed-polarized undulator configuration for an free electron laser oscillator (XFELO) produce arbitrarily polarized pulses in the hard region. A numerical example utilizing parameters Shanghai High-Repetition-Rate XFEL and Extreme Light Facility (SHINE) presented demonstrate generation controllable, 99.9% degree 20 kHz...
High-density electron-bunch train--based tunable coherent terahertz radiation with a narrow spectral bandwidth is highly essential for many scientific applications. Here we propose scheme to produce ultrahigh-peak-current (more than 10 kA) trains picosecond spacing the generation of such sources. Passing through plasma section and interacting self-excited nonlinear wake, beam gains ``sawtooth'' energy modulation. By means magnetic optics, it then effectively converted into density modulation...
X-ray free electron laser oscillators (XFELOs) are future light sources that produce fully coherent hard x-ray pulses. Based on the low-gain principle, XFELO traps pulses in an optical cavity composed of multiple Bragg-reflecting mirrors have high reflectivity a bandwidth about ten meV. The crystal exposed to intense beams subject thermal deformations would shift and distort Bragg curve. Therefore, stability operation depends ability maintain reflection under such load. A new approach was...
The characteristics of a coherent tunable terahertz-wave source have been experimentally investigated in detail. By using difference frequency generation as result stimulated Raman scattering by polaritons MgO:LiNbO3 crystals, the signal wave was continuously tuned range 1.069–1.075 μm, which corresponded to wide from 227 104 μm (1.3 2.9 THz). highest output pulse energy at pumping level 44 mJ/pulse 1.8 with 20 mW seeder injection, and terahertz peak power 139 wavelength 143 μm. This has...
The first hard X-ray free electron laser (XFEL) facility in China, the Shanghai High-Repetition-Rate XFEL and Extreme Light Facility (SHINE), is under construction, which allows for generating pulses photon energy range from 3 keV to 25 keV. To produce with up keV, FEL-III undulator line of SHINE employs superconducting undulators. However, smaller gap poses serious wakefield effect reducing FEL power, compared normal planar undulator. For a setup design optimization, performance are...
This study entailed the development of a high-gradient modulation microbunching for traditional radiation frequency accelerators using minimized system driven by relativistic Laguerre–Gaussian (LG) laser in three-dimensional particle-in-cell (PIC) simulations. It was observed that LG could compress transverse dimension beam to within 0.7 µm radius (divergence≈4.3 mrad), which is considerably lower than case tuned Gaussian laser. In addition, electron be efficiently modulated high degree...
The X-ray free-electron laser oscillator (XFELO) has received significant attention due to its ability produce fully coherent, high-brightness, and highly stable beams. Despite these advantages, the operation of XFELO can be impeded by surrounding environment. Specifically, vibrations optical components within cavity lead poor alignment, which diminish interaction between light electrons in undulator. Consequently, quality output X-rays may compromised. This study aims investigate impact...
X-ray vortices carrying tunable Orbital Angular Momentum (OAM) are an emerging tool for characterization technology. However, in contrast to the generation of vortex beams visible wavelength region, a controlled manner has proved challenging. Here, we overcome this challenge using free-electron laser oscillator (XFELO), which can produce intense coherent X-rays with switchable OAM. Using pinhole mirror XFELO, scheme adjusts only kinetic energy electron beam that be programmed dynamically...
The undulator line of the Shanghai soft X-ray Free-electron Laser facility (SXFEL) has very tight tolerances on straightness electron beam trajectory. However, trajectory cannot meet lasing requirements due to influence position, launch angle and quadrupole offsets. Traditional mechanical alignment can only control rms offsets about 100 μm, which is far from reaching requirement. Further orbit correction be achieved by beam-based (BBA) method based energy variations. K modulation used...
The undulator line of the Shanghai soft X-ray Free-electron Laser facility (SXFEL) has very tight tolerances on straightness electron beam trajectory. However, trajectory cannot meet lasing requirements due to influence position, launch angle and quadrupole offsets. Traditional mechanical alignment can only control rms offsets about 100 $\mu$m, which is far from reaching requirement. Further orbit correction be achieved by beam-based (BBA) method based energy variations. K modulation used...