A5048940763- Solid State Laser Technologies
- Advanced Fiber Laser Technologies
- Laser Design and Applications
- Laser-Matter Interactions and Applications
- Laser-Plasma Interactions and Diagnostics
- Photorefractive and Nonlinear Optics
- Laser-induced spectroscopy and plasma
- Optical Systems and Laser Technology
- High-pressure geophysics and materials
- Magneto-Optical Properties and Applications
- Laser Material Processing Techniques
- Plasma Diagnostics and Applications
- Plasma Applications and Diagnostics
- Semiconductor Lasers and Optical Devices
- Luminescence Properties of Advanced Materials
- Optical properties and cooling technologies in crystalline materials
- Spectroscopy and Laser Applications
- Photonic Crystal and Fiber Optics
- Photonic and Optical Devices
- Atomic and Molecular Physics
- Glass properties and applications
- Cold Atom Physics and Bose-Einstein Condensates
- Photocathodes and Microchannel Plates
- Quantum optics and atomic interactions
- Atomic and Subatomic Physics Research
Osaka University
2015-2024
Institute for Laser Technology
2007-2022
Japan Science and Technology Agency
2008-2010
Hamamatsu Photonics (Japan)
2006-2008
Instituto de Investigaciones Químicas
2007-2008
Kyoto University
2007-2008
Kyoto University Institute for Chemical Research
2008
Hamamatsu Photonics (United Kingdom)
2001-2008
University of Fukui
2006
Advanced Science Research Center
2000-2004
The quest for the inertial confinement fusion (ICF) ignition is a grand challenge, as exemplified by extraordinary large laser facilities. Fast isochoric heating of pre-compressed plasma core with high-intensity short-pulse an attractive and alternative approach to create ultra-high-energy-density states like those found in ICF sparks. This avoids quench caused hot spark mixing surrounding cold fuel, which crucial problem currently pursued scheme. High-intensity lasers efficiently produce...
Abstract Using one of the world most powerful laser facility, we demonstrate for first time that high-contrast multi-picosecond pulses are advantageous proton acceleration. By extending pulse duration from 1.5 to 6 ps with fixed intensity 10 18 W cm −2 , maximum energy is improved more than twice (from 13 33 MeV). At same time, laser-energy conversion efficiency into MeV protons enhanced an order magnitude, achieving 5% above duration. The energies observed discussed using a plasma expansion...
As the first demonstration of Faraday effect in a TGG ceramics, its Verdet constant at 1053 nm is evaluated to be 36.4 rad/Tm room temperature which same as that single crystal. In addition, dependence obtained experimentally. At liquid helium temperature, it 87 times greater than temperature.
We report a high-average-power and high-pulse-energy diode-pumped Nd:glass laser amplifier system consisting of two thermally-edge-controlled zigzag slab amplifiers stimulated Brillouin scattering mirror. This phase-conjugated produces an average power 213 W at 10 Hz in 8.9 ns pulse (2.4 GW peak power) with optical-to-optical conversion efficiency 11.7% near-diffraction-limited beam. To the best our knowledge, this is highest performance from Nd:glass-based ever built.
Abstract The rapid development of the optical-cycle-level ultra-fast laser technologies may break through bottleneck traditional ultra-intense [i.e., Petawatt (PW, 10 15 W) currently] and enable generation even higher peak-power/intensity lasers. Herein, we simulate an ultra-broadband concept for realization Exawatt-class (EW, 18 high peak-power laser, where wide-angle non-collinear optical parametric chirped-pulse amplification (WNOPCPA) is combined with thin-plate post-compression. A...
A diode-pumped chirped-pulse regenerative amplifier with a cooled Yb:YLF crystal has been developed. The output pulse energy is 30 mJ at 20-Hz repetition rate. high effective extraction efficiency of 68% obtained, which attributed to reduced saturation fluence low temperature and during amplification. After compression by use parallel grating pair, 18-mJ 795-fs duration are obtained.
A petawatt laser for fast ignition experiments (LFEX) system [N. Miyanaga et al., J. Phys. IV France 133, 81 (2006)], which is currently capable of delivering 2 kJ in a 1.5 ps pulse using 4 beams, has been constructed beside the GEKKO-XII facility demonstrating efficient heating dense plasma up to temperature under auspices Fast Ignition Realization EXperiment (FIREX) project [H. Azechi Nucl. Fusion 49, 104024 (2009)]. In FIREX experiment, cone attached spherical target containing fuel...
An efficient high-power laser operation has been demonstrated by using a cryogenic Yb:YAG composite ceramic with total-reflection active-mirror arrangement. The ceramic, which had no high-reflection coating and was cooled liquid nitrogen directly, showed four-level even at 67 kW/cm(3) of high pump density. A 273 W cw output power obtained 65% optical efficiency 72% slope efficiency.
Based on the successful result of fast heating a shell target with cone for beam injection at Osaka University in 2002 using PW laser (Kodama et al Nature 418 933), FIREX-1 project was started 2004. Its goal is to demonstrate fuel up 5 keV an upgraded beam. For this purpose, LFEX laser, which can deliver energy to10 kJ 0.5–20 ps pulse its full spec, has been constructed addition Gekko-XII system Institute Laser Engineering, University. It activated and became operational since 2009....
A MOPA laser system for high pulse energy and average power has been developed by using a cryogenic Yb:YAG. In the regenerative amplifier with our original TRAM architecture, energies of 6.5 1.5 mJ were obtained at repetition rate 200 Hz 1 kHz, respectively. An optical efficiency was as ηo-o = 9.3% an excellent beam quality M 2 < 1.1, which ensured that Yb:YAG had thermal strength. The following four pass rod showed 140 100 Hz. Both 30% slope ηs 44% efficient operation could be realized...
The temperature dependence of the thermo-optic effects in single crystal and ceramic TGG were evaluated by using Fizou interferometer method. refractive index thermal expansion are significantly improved at low for both ceramics crystals. Our estimation a figure merit indicated that cooled to liquid nitrogen can reduce wave-front distortion factor up 4.7 with respect 300 K, birefringence 12 those K.
We have demonstrated the continuous-wave operation of a highly efficient 2.8 μm Er-doped Lu2O3 ceramic laser at room temperature. An Er:Lu2O3 with doping concentration 11 at.% afforded slope efficiency 29% and an output power 2.3 W pumping 10 W. To our knowledge, these are highest obtained to date for μm. In addition, we prepared ceramics various concentrations determined their emission cross sections by fluorescence lifetime measurements spectroscopy.
Fast isochoric laser heating is a scheme to heat matter with relativistic intensity ($>{10}^{18}\text{ }\text{ }\mathrm{W}/{\mathrm{cm}}^{2}$) pulse for producing an ultrahigh-energy-density (UHED) state. We have demonstrated efficient fast of compressed dense plasma core multipicosecond kilojoule-class petawatt and assistance externally applied kilotesla magnetic fields guiding electrons the plasma. A UHED state 2.2 PPa achieved experimentally 4.6 kJ total energy that one order magnitude...
High average power lasers with a high pulse energy are of considerable interest in various fields such as high-energy-density physics. Light-absorbing edge cladding is effective suppressing parasitic oscillations high-pulse-energy disk lasers; however, the large amount heat generated from can affect laser medium. We develop an improved conduction-cooled active-mirror double-sided cooled-edge cladding. A stable output 10 J at repetition rate 100 Hz was achieved using six...
Since the approval of first phase Fast-Ignition Realization Experiment (FIREX-I), we have devoted our efforts to designing advanced targets and constructing a petawatt laser, which will be most energetic laser in world. Scientific technological improvements are required efficiently heat core plasma. There two methods that can used enhance coupling efficiency heating thermal energy compressed plasma: adding low- Z foam layer inner surface cone employing double cone. The implosion performance...
The world's largest peta watt (PW) laser LFEX, which delivers energy up to 2 kJ in a 1.5 ps pulse, has been constructed beside the GEKKO XII at Institute of Laser Engineering, Osaka University. GEKKO-LFEX facility enables creation materials having high-energy-density do not exist naturally on Earth and have an density comparable that stars. High-energy-density plasma is source safe, secure, environmentally sustainable fusion energy. Direct-drive fast-ignition intensively studied this under...
Laser pulse contrast exceeding 1011 was demonstrated on a kilojoule-class petawatt laser for fast ignition experiments (LFEX) system [J. Phys. IV France133, 81 (2006)10.1051/jp4:2006133016] by implementing 2 in. plasma mirror. beams of up to 1.2 kJ striking the mirror with duration 1.5 ps were reflected and focused onto target without significant distortions in focal spot. Transmitted light from reveals that it has high reflectivity before main peak. The estimated at 1 ns No preformed...
We have demonstrated a passively Q-switched Er:Lu2O3 ceramics laser using monolayer graphene saturable absorber (SA). Stable pulsed operation with watt-level average power was achieved by compact linear cavity without focusing on the SA. This is first demonstration of mid-IR A maximum pulse energy 9.4 μJ and peak 33 W were 247 ns duration. To our knowledge, this shortest duration, highest energy, obtained SA in 3 μm wavelength region.
Abstract During the process of Bessel beam generation in free space, spatiotemporal optical wave-packets with tunable group velocities and accelerations can be created by deforming pulse-fronts injected pulsed beams. So far, only one determined motion form (superluminal or luminal subluminal for case velocity; accelerating uniform-motion decelerating acceleration) could achieved a single propagation path. Here we show that deformed well-designed axisymmetric distributions (unlike conical...
Abstract Three-dimensional (3-D) light solitons in space–time, referred to as bullets, have many novel properties and wide applications. Here we theoretically show how the combination of diffraction-free beam ultrashort pulse spatiotemporal-coupling enables creation a straight-line propagation bullet with freely tunable velocity acceleration. This could propagate constant superluminal or subluminal velocity, it also counter-propagate very fast (e.g., − 35.6 c ). Apart from uniform motion, an...
We have demonstrated a diode-pumped Yb:LiYF4 (Yb:YLF) laser oscillator for the first time to our knowledge. A wide tuning range of 25 nm and high slope efficiency 50% were obtained at laser-diode pump intensity 100 kW/cm2. Emission absorption spectra Yb:YLF crystal 8 K represent gain width 38 nm, indicating efficient operation similar that four-level system with reduced saturation fluence 11 J/cm2.
A diode-pumped, cryogenic-cooled Yb:YAG regenerative amplifier utilizing gain-narrowing has been developed. 1.2-ns chirped-seed pulse was simultaneously amplified and compressed in the amplifier, which generated a 35-ps with ~8-mJ of energy without compressor. Second-harmonics used to pump picosecond two-color optical parametric amplification.