A5024741065- Particle Accelerators and Free-Electron Lasers
- Gyrotron and Vacuum Electronics Research
- Particle accelerators and beam dynamics
- Laser Design and Applications
- Laser-Plasma Interactions and Diagnostics
- Terahertz technology and applications
- Photocathodes and Microchannel Plates
- Advanced X-ray Imaging Techniques
- Photonic and Optical Devices
- 2D Materials and Applications
- Magnetic confinement fusion research
- Laser-Matter Interactions and Applications
- Microwave Imaging and Scattering Analysis
- Magnetic properties of thin films
- Atomic and Subatomic Physics Research
- Laser Material Processing Techniques
- Geophysics and Sensor Technology
- Nuclear Physics and Applications
- Radiation Therapy and Dosimetry
- Advancements in Photolithography Techniques
- Microwave Engineering and Waveguides
- Solid State Laser Technologies
- Mechanical and Optical Resonators
- Radiation Detection and Scintillator Technologies
- Energetic Materials and Combustion
Kansai University
2015-2024
Toho University
2024
Osaka University
1993-2017
Tokyo Institute of Technology
2014-2017
Institute for Laser Technology
1993-2017
Kyoto University
1999-2017
University of Hyogo
2017
University of Electronic Science and Technology of China
2017
University of Fukui
2017
Osaka Sangyo University
2009
Several transition-metal dichalcogenides exhibit a striking crossover from indirect to direct band gap semiconductors as they are thinned down single monolayer. Here, we demonstrate how an electronic structure characteristic of the isolated monolayer can be created at surface bulk MoS2 crystal. This is achieved by intercalating potassium in interlayer van der Waals gap, expanding its size while simultaneously doping electrons into conduction band. Our angle-resolved photoemission...
Abstract In special relativity, four-vectors, such as space–time, energy–momentum and electromagnetic potential vectors, follow the Lorentz transformation. The transformations of space–time vectors have been tested by time dilation rest mass energy experiments, respectively. However, transformation potentials has never directly demonstrated in experiments due to limitations diagnostics. Here we show spatiotemporal electric-field profiles around a highly energetic electron beam with...
This letter reports an approach to realize coherent radiation at the fundamental frequency of wave that is resonant with electron beam in a Smith-Purcell (SP) free-electron laser (FEL). We found two-dimensional grating structure equipped dielectric substrate could provide electromagnetic mode which shows property surface vacuum region where beam-wave interaction occurs, and operates as radiative region. Thus, holding medium energy radiate frequency, different from typical radiates only...
We report an approach to efficiently generate terahertz radiation from a combined periodic structure. The proposed configuration is composed of two metallic slit arrays deliberately designed with different length, width and depth. found that the combination could provide special electromagnetic modes, which exhibit nonradiative property above surface one array radiative inside other one. An electron beam holding proper energy resonate those modes strong directional radiations in regime,...
Extraordinary (X) waves are perpendicularly injected for electron Bernstein (B) wave heating into an Ohmically heated plasma from the inboard side in WT-3 tokamak. Measurements show that absorption does not take place at cyclotron resonance layer nor upper hybrid layer, but happen midway between them. This is consistent with ray tracing prediction, i.e., poloidal field and inhomogeneity of toroidal lead B to have a large parallel refractive index N( parallel) (>1), damped away via...
This letter reports a theory to calculate the growth rate and start current of Smith–Purcell free-electron laser, which is promising radiation source in terahertz domain. A two-dimensional model was used investigate interaction between sheet electron beam surface wave above lamellar grating. After deriving from dispersion equation, carefully estimated by considering power flow The agreement predictions our results particle-in-cell simulations acceptable.
We have observed the oscillation of a waveguide mode free-electron laser using coherent synchrotron radiation emitted from electron bunches. The was at 2.73 mm with linewidth 0.4%. This spectral selection attributed to dispersion in waveguide. found that oscillating had same group velocity as electrons passing through wiggler field.
Institute of Free-Electron Laser is one the FEL supplying facilities for 2000 hours in a year. The system consists two RF-linacs and five wigglers, covers wavelength range from 0.28 to 100 µm. In operational period April 2001 March 2002, mid-infrared light 5 20 µm was supplied over 40 cooperative research programs on fields semiconductor, bio-medical environmental chemistry. An effort still carrying improve property light.
We report on a detailed analysis of the influence random spectral phase noise temporal contrast an ultra-high intensity laser pulse. accurately evaluate impact stretcher and compressor optics pedestal pulse by precise quantitative characterization surface. The surface roughness tens nanometers causes noise, which reduce coherence main generates noisy structure around A degradation few orders magnitude is estimated with noise.
Grating with Bragg reflectors for the Smith–Purcell free-electron laser is proposed to improve reflection coefficient, resulting in enhancing interaction of surface wave electron beam and, consequently, relax requirements beam. With help particle-in-cell simulations, it has been shown that usage may growth rate, shorten time device reach saturation, and lower start current operation a laser.
A pressure driven m=1/n=1 mode is excited by lower hybrid current drive in the WT-3 tokamak [T. Maehara et al., Nucl. Fusion 38, 39 (1998)]. The excitation of accompanied with decrease magnetic shear and peaking soft x-ray emissivity profile inside q=1 surface. crescent-shaped structure appeared on contour map consistent that quasi-interchange mode. m=1 can be suppressed electron cyclotron heating near range location resonance layer effective for complete suppression much wider time scale...