A5039262880- Laser-Plasma Interactions and Diagnostics
- Laser-Matter Interactions and Applications
- Laser-induced spectroscopy and plasma
- Laser Design and Applications
- Advanced X-ray Imaging Techniques
- Arctic and Antarctic ice dynamics
- Atomic and Molecular Physics
- Laser Material Processing Techniques
- High-pressure geophysics and materials
- Radio Wave Propagation Studies
- Atmospheric aerosols and clouds
- Particle Accelerators and Free-Electron Lasers
- Diamond and Carbon-based Materials Research
- X-ray Spectroscopy and Fluorescence Analysis
- Electron and X-Ray Spectroscopy Techniques
- Ocular and Laser Science Research
- Solid State Laser Technologies
- Underwater Acoustics Research
- Antenna Design and Optimization
- Optical and Acousto-Optic Technologies
- Geophysics and Gravity Measurements
- Optical Wireless Communication Technologies
- Orbital Angular Momentum in Optics
- Optical Systems and Laser Technology
- Advanced Fiber Laser Technologies
National Institutes for Quantum Science and Technology
2016-2024
Fujitsu (Japan)
2021-2024
Kansai Photon Science Institute
2014-2023
Japan Synchrotron Radiation Research Institute
2017-2023
Nitto RIKEN (Japan)
2023
SPring-8
2019-2022
Osaka University
2010-2018
Akita Prefectural University
2018
Japan Science and Technology Agency
2017
Moscow Engineering Physics Institute
2017
Abstract We report on experimental investigations of proton acceleration from solid foils irradiated with PW-class laser-pulses, where highest cut-off energies were achieved for temporal pulse parameters that varied significantly those an ideally Fourier transform limited (FTL) pulse. Controlled spectral phase modulation the driver laser by means acousto-optic programmable dispersive filter enabled us to manipulate shape last picoseconds around main and study effect thin foil targets. The...
Laser-driven ion sources are a rapidly developing technology producing high energy, peak current beams. Their suitability for applications, such as compact medical accelerators, motivates development of robust acceleration schemes using widely available repetitive ultraintense femtosecond lasers. These applications not only require beam but also place demanding requirements on the source stability and controllability. This can be seriously affected by laser temporal contrast, precluding...
A high-contrast high-intensity petawatt-class Ti:sapphire chirped-pulse amplification laser has been developed for research on high field science. saturable absorber and a low-gain optical parametric preamplifier in the front-end have improved temporal contrast system to ∼ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math>$2 \times 10^{12}$</tex-math></inline-formula> subnanosecond time scale at ∼70 TW power level. In addition...
Abstract High-intensity lasers interacting with solid foils produce copious numbers of relativistic electrons, which in turn create strong sheath electric fields around the target. The proton beams accelerated such have remarkable properties, enabling ultrafast radiography plasma phenomena or isochoric heating dense materials. In view longer-term multidisciplinary purposes (e.g., spallation neutron sources cancer therapy), current challenge is to achieve energies well excess 100 MeV,...
We developed a compact plasma-based focusing optic that, in one step, increases the peak intensity of ultrahigh-intensity lasers without modifying laser system itself. By using with extremely small f-number (f/0.4), we have experimentally demonstrated fivefold reduction focal spot size (from 4.4 to 0.9 microm), thus producing an at least eightfold enhancement light intensity. This innovative opens way for study high-energy-density and high-field science intensities greater than presently available.
We described the output performance and temporal quality enhancement of J-KAREN-P petawatt laser facility. After wavefront correction using a deformable mirror, focusing with an f/1.3 off-axis parabolic mirror delivered peak intensity 1022 W/cm2 at 0.3 PW power levels. Technologies to improve contrast were investigated tested. The origins pre-pulses generated by post-pulses identified elimination most removal wedged optics was achieved. A cascaded femtosecond optical parametric amplifier...
Abstract Tight focusing with very small f -numbers is necessary to achieve the highest at-focus irradiances. However, tight imposes strong demands on precise target positioning in-focus on-target irradiance. We describe several near-infrared, visible, ultraviolet and soft hard X-ray diagnostics employed in a ∼10 22 W/cm 2 laser–plasma experiment. used nearly 10 J total energy femtosecond laser pulses focused into an approximately 1.3-μm focal spot 5–20 μm thick stainless-steel targets....
Spectrally-peaked proton beams of high charge (, , nC ) have been observed from the interaction an intense laser ( W cm−2) with ultrathin CH foils, as measured by spectrally-resolved full beam profiles. These are reproducibly generated for foil thicknesses 5–100 nm, and exhibit narrowing divergence decreasing target thickness down to 5 nm. Simulations demonstrate that narrow energy spread feature is a result buffered acceleration protons. The radiation pressure at front results in asymmetric...
Abstract Interaction of a solid material with focused, intense pulses high-energy photons or other particles (such as electrons and ions) creates strong electronic excitation state within an ultra-short time on ultra-small spatial scales. This offers the possibility to control response scale less than nanometer—crucial for next generation nano-devices. Here we create craters surface silicon substrate by focusing single femtosecond extreme ultraviolet pulse from SACLA free-electron laser. We...
Abstract We have experimentally improved the temporal contrast of petawatt J-KAREN-P laser facility. investigated how generation pre-pulses by post-pulses changes due to overlap between stretched pulse and post-pulse in a chirped-pulse amplification system. shown that time at which pre-pulse is generated its shape are related difference main post-pulse. With this investigation, we found identified origins demonstrated removal most eliminating with wedged optics. also impact stretcher optics...
Abstract Wave propagation in an anisotropic turbulent medium is studied assuming that the anisotropy coefficient η constant for all scales of inhomogeneities. A qualitative method studying amplitude and phase fluctuations developed. Formulae have been obtained structure functions scintillation index with spectrum power 3<μ<5 η≥1. Two particular cases detail—propagation along across axis stretching irregularities. During a short inhomogeneities are decreasing function turn out to be ημ−2...
A high repetition rate scintillator-based transverse beam profile diagnostic for laser-plasma accelerated proton beams has been designed and commissioned. The profiler uses differential filtering to provide coarse energy resolution a flexible design allow optimisation expected range trade-off between spatial depending on the application. plastic scintillator detector, imaged with standard 12-bit scientific camera, allows data be taken at rate. An algorithm encompassing non-linearity is...
An experimental platform using X-ray free-electron laser (XFEL) pulses with high-intensity optical is open for early users' experiments at the SACLA XFEL facility after completion of commissioning. The combination hard and provides capabilities to new frontiers laser-based high-energy-density science. During commissioning phase, characterization has been carried out combinative utilization as well development instruments basic diagnostics user experiments. overview current presented.
It is shown theoretically that the spatial coherence radius of field a single-mode laser beam traveling in turbulent atmosphere exceeds plane and spherical waves. established this excess greatest case strong fluctuations intensity. A study made influence partial light source on field. demonstrated becomes independent diffraction size when random phase shifts increase sufficiently over distance equal to first Fresnel zone. solution obtained problem turbulence-induced spreading image partly...
Near-infrared radiation around 1000 nm generated from the interaction of a high-density MeV electron beam, obtained by impinging an intense ultrashort laser pulse on solid target, with metal grating is observed experimentally. Theoretical modeling and particle-in-cell simulation suggest that caused Smith-Purcell mechanism. The results here indicate tunable terahertz tens GV/m field strength can be achieved using appropriate parameters.
Ultra-high intensity femtosecond lasers have now become excellent scientific tools for the study of extreme material states in small-scale laboratory settings. The invention chirped-pulse amplification (CPA) combined with titanium-doped sapphire (Ti:sapphire) crystals enabled realization such lasers. pursuit ultra-high science and applications is driving worldwide development new capabilities. A petawatt (PW = 1015 W), (fs 10−15 s), repetitive (0.1 Hz), high beam quality J-KAREN-P (Japan...
A study is done for the angular dependence of back scattered signal power from anisotropic turbulent inhomogeneities which described in Born approximation with help spectrum model constant anisotropy. The aspect sensitivity obtained theoretically are compared published data and estimations made anisotropy coefficient low middle atmosphere.
We present results from the SPring-8 Angstrom Compact free electron LAser (SACLA) XFEL facility, using a high intensity ($\sim\!10^{20}\,$W/cm$^2$) X-ray pump probe scheme to observe changes in ionic structure of silicon induced by heating electrons. By avoiding Laue spots scattering signal single crystalline sample, we rapid rise diffuse scattering, which attribute loss lattice order and transition liquid state within 100 fs irradiation, timescale agrees well with first principles...
We present results from the SPring-8 Angstrom Compact free electron LAser (SACLA) X-ray laser (XFEL) facility, using an pump, probe scheme to observe ultrafast changes in structure of heated graphite. The 9.8 keV XFEL beam was focused give intensity on order ∼ 1019 W/cm2, and evolution diffraction pattern observed up delays 300 fs. interplanar peaks weaken significantly within 10s femtoseconds, but in-plane orders i.e. those with Miller Index (hk0), persist fs, signal increasing. interpret...
We report on a new approach to measure the accumulated B-integral in regenerative and multipass amplifier stages of ultrashort-pulse high-power laser systems by B-integral-induced coupling between delayed test post-pulses main pulse. A numerical model for such non-linear pulse is presented compared data taken at Draco with self-referenced spectral interferometry (SRSI). The dependence its operation mode enables optimization strategies extracted energy vs. collected B-integral. technique here...
Abstract We report on the design and characterization of plasma mirror system installed J-KAREN-P laser at Kansai Photon Science Institute, National Institutes for Quantum Technology. The reflectivity single exceeded 80%. In addition, temporal contrast was improved by two orders magnitude 1 ps before main pulse. Furthermore, near-field spatial distribution after kept constant fluence less than 100 kJ/cm 2 . also present results investigating difference fluctuation in energy, pulse width...