A5054227002- Particle Accelerators and Free-Electron Lasers
- Advanced X-ray Imaging Techniques
- Laser Design and Applications
- Gyrotron and Vacuum Electronics Research
- Laser-Plasma Interactions and Diagnostics
- Particle accelerators and beam dynamics
- Laser-Matter Interactions and Applications
- Advanced Fiber Laser Technologies
- Solid State Laser Technologies
- Advanced Radiotherapy Techniques
- Radiation Detection and Scintillator Technologies
- Photocathodes and Microchannel Plates
- Atomic and Subatomic Physics Research
- Photonic and Optical Devices
- Nuclear Physics and Applications
- Superconducting Materials and Applications
- Pulsed Power Technology Applications
- Terahertz technology and applications
- Cold Atom Physics and Bose-Einstein Condensates
- Advanced Electron Microscopy Techniques and Applications
- Optical Polarization and Ellipsometry
- Cultural Heritage Materials Analysis
- Advanced X-ray and CT Imaging
- Laser Material Processing Techniques
- Photorefractive and Nonlinear Optics
Waseda University
2014-2025
Czech Academy of Sciences, Institute of Physics
2022-2024
A free-electron laser (FEL) is a robust tool for studying the interaction of intense X-rays with matter. In this study, we investigate damage threshold and morphology fused silica irradiated by extreme ultraviolet femtosecond pulses FEL. The experimental results indicate superiority FEL processing. FEL-damage at wavelength 13.5 nm 0.17 J/cm2, which 20 times lower than that near infrared (NIR) laser. relationship between crater depth fluence reveals effective absorption length αeff−1 = 58 nm....
We present a new design for rf electron gun to be used in ultrashort ($\ensuremath{\sim}1\text{ }\text{ }\mathrm{ps}$) bunch generation. Using both simulation and measurement we evaluated the principle of this type were able confirm an During simulation, length less than 100 fs(rms) with $100\text{ }\mathrm{pC}/\text{bunch}$ charge was confirmed at optimum operating condition. The is produce linearly distributed longitudinal phase space by using attached output cell specially designed energy...
We report a high power Yb:YAG thin disk laser with cylindrical vector polarization incorporating an intracavity S-waveplate. By adjusting the angle of S-waveplate in resonator, we could select state output, radial or azimuthal polarization, resonator. The yielded ⪆10 W both polarized output for incident pump 131 continuous-wave mode operation, corresponding to slope efficiency ⪆18%. Output characteristics will be discussed detail.
We demonstrate a highly stable Ho:YAG thin-disk Q-switched laser with direct in-band diode pumping, generating 5.3-mJ, 2.09-µm nanosecond pulses peak power of 18 kW in single mode. Cavity-dumped regime results will also be reported.
At Waseda University, we have been studying for high quality electron beam generation using 1.6 cell Cesium Telluride (Cs-Te) photocathode rf-gun. We use as the source, which can generate high-quality such low emittance, and short bunch. The performance of is evaluated mainly in terms quantum efficiency (Q.E.) lifetime. Cs-Te known Q.E. about 10% with UV light relatively longer lifetime among semiconductor photocathodes. Since it a hard environment inside gun, necessary to replace every...
Ultrashort electron bunches are becoming increasingly important for applications such as free-electron lasers, time-resolved diffraction/microscopy, and advanced accelerator concepts. We report femtosecond bunch generation with a unique rf gun its precise measurement using transverse deflecting cavity. A length of $323\ifmmode\pm\else\textpm\fi{}13\text{ }\text{ }\mathrm{fs}$ 120 pC ($\ensuremath{\sim}7.5\ifmmode\times\else\texttimes\fi{}{10}^{8}\text{ }\mathrm{electrons}$) was achieved at...
Optical enhancement cavities enabling laser pulses to be coherently stacked in free space are used several applications enhance accessible optical power. In this study, we develop an cavity that accumulates harmonically mode-locked with a self-resonating mechanism for X-ray sources based on laser-Compton scattering. particular, Fabry-Perot composed of 99% reflectance mirrors maintained the resonance feedback-free fashion more than half hour and automatically resumed accumulation even if...
An X-ray source via laser-Compton scattering has the advantage of small source, energy tunability and quasi-monochromaticity is expected to be applied in a wide range fields such as industry medical care. In scattering, luminosity, which represents collision frequency between electrons photons, very important. Increasing luminosity strongly required for increasing scattered photon flux. One way increase tilting electron bunches at point, called crab crossing. It create head-on artificially....
We have been studying a high quality electron beam generated by photocathode RF gun at Waseda University. The is applied to pulse radiolysis experiment, laser Compton scattering for soft X-ray generation, and THz imaging experiment using coherent radiation. In these applications, longitudinal parameters of the are important. For this reason, we developed deflector system which can directly convert distribution transverse with temporal resolution, performed profile measurements an from gun....
Crab crossing of electron beam and laser pulse enables head-on collision in laser-Compton scattering. We will report prospects crab scattering a suitable system based on thin-disk regenerative amplifier.
To develop a detector with an effective area large enough to observe extensive air shower, we studied method of detecting radio waves generated via the transition radiation process by charged particles in shower. Characteristics were investigated using beam accelerators and antennas . When about 430x10^9 electrons kinetic energy 4.7 MeV crossed titanium film into air, pulse emitted was measured standard dipole antenna bandwidth 800 - 880 MHz. The height at position 1.2 m away from source...