A5017579411- Solid State Laser Technologies
- Advanced Fiber Laser Technologies
- Laser-Matter Interactions and Applications
- Laser Design and Applications
- Laser-Plasma Interactions and Diagnostics
- Laser-induced spectroscopy and plasma
- Photorefractive and Nonlinear Optics
- Laser Material Processing Techniques
- Photonic Crystal and Fiber Optics
- Advanced Fiber Optic Sensors
- Spectroscopy and Laser Applications
- Terahertz technology and applications
- Magneto-Optical Properties and Applications
- Photonic and Optical Devices
- Optical properties and cooling technologies in crystalline materials
- Semiconductor Lasers and Optical Devices
- Optical Systems and Laser Technology
- Gyrotron and Vacuum Electronics Research
- Diamond and Carbon-based Materials Research
- Luminescence Properties of Advanced Materials
- Ocular and Laser Science Research
- Ion-surface interactions and analysis
- Glass properties and applications
- High-pressure geophysics and materials
- Semiconductor Quantum Structures and Devices
Kyoto University
2010-2024
Osaka University
2014-2023
Kyoto University Institute for Chemical Research
2008-2023
Kyoto Bunkyo University
2009-2023
Institute for Laser Technology
2003-2022
Instituto de Investigaciones Químicas
2007-2022
Meiji University
2011
Hamamatsu Photonics (United Kingdom)
2007-2008
University of Fukui
2002
Nihon University
1993
Periodic grating structures self-formed on a metal surface under the irradiation of femtosecond laser pulse are characterized by spaces which shorter than wavelength, as well dependence fluence. This Brief Report presents different interpretation these features in terms process parametric decay light to plasma waves. Depending electron density, with lengths 680 nm short 400 can be produced for 800 wavelength result interaction pulses laser-produced plasma.
A 24 W liquid-cooled CW 3 microm fiber laser with a multimode-core Er-doped ZBLAN has been developed. The output power of and an optical-to-optical efficiency 14.5% (with respect to incident pump power) were obtained 975 nm diode pumping. Efficient cooling was implemented by combination fluid over the entire length conductive at both end faces fiber. Consequently, stable high-power operation demonstrated. To our knowledge, this is highest laser. Furthermore, high can be further scaled up,...
Periodic structures self-formed on the surface of several metals under femtosecond laser-pulse irradiation are investigated by electron microscopy. For self-formation periodic gratings metal surfaces, interspaces depend laser fluence. This dependence is same for all metals, although range fluence in which formed differs between metals. The can be explained generation a plasma wave through parametric decay light [S. Sakabe, M. Hashida, S. Tokita, Namba, and K. Okamuro, Phys. Rev. B 79, 033409...
A diode-pumped, actively Q-switched 2.8 μm fiber laser oscillator with an average output power of more than 12 W has been realized through the use a 35 core erbium-doped ZBLAN and acousto-optic modulator; to our knowledge, this is first 3 pulsed in 10 class. Pulse energy up 100 μJ pulse duration down 90 ns, corresponding peak 0.9 kW, were achieved at repetition rate 120 kHz.
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...
We report, for the first time, to best of our knowledge, a femtosecond mode-locked Fe:ZnSe laser. Passive mode locking is implemented using graphene as saturable absorber. The laser operates at 4.4 µm with repetition frequency 100 MHz and 415 mW output power pumped by fiber 7 W Er:ZBLAN pulse duration about 732 fs retrieved from first-order autocorrelation function. Additionally, we observe pulsed nanosecond oscillation under continuous-wave pumping strong amplitude modulation caused Kerr...
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 have developed a diode-pumped tunable 3 μm fiber laser with cw output power of the order 10 W use an erbium-doped ZBLAN fiber. A tunability range 110 nm (2770 to 2880 nm) between 8 and 11 was demonstrated. As pump increased, center wavelength shifted toward longer wavelengths, but width largely unaffected. The total for various levels 170 (2710 nm). To our knowledge, this is highest performance (output tunability) obtained from laser.
We report the first experimental demonstration of longitudinal compression laser-accelerated electron pulses. Accelerated by a femtosecond laser pulse with an intensity ${10}^{18}\text{ }\text{ }\mathrm{W}/{\mathrm{cm}}^{2}$, energy around 350 keV and relative momentum spread about ${10}^{\ensuremath{-}2}$ was compressed to 500-fs at distance 50 cm from source using magnetic compressor. This used generate clear diffraction pattern gold crystal in single shot. method solves space-charge...
Abstract Terahertz pulses trapped as surface waves on a wire waveguide can be flexibly transmitted and focused to sub-wavelength dimensions by using, for example, tapered tip. This is particularly useful applications that require high-field pulses. However, the generation of strong terahertz remains challenge. Here, ultrafast field propagation along metal driven femtosecond laser pulse with an intensity 10 18 W/cm 2 characterized electron deflectometry. From experimental numerical results,...
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...
We demonstrate the first actively Q-switched fiber laser operating in 3.5 μm regime. The dual-wavelength pumped system makes use of an Er3+ doped ZBLAN and a germanium acousto-optic modulator. Robust Q-switching saw pulse energy 7.8 μJ achieved at repetition rate 15 kHz, corresponding to peak power 14.5 W.
In this Letter, we report a compact and robust coherent source, operating in mid-infrared (IR) based on the Fe:ZnSe chalcogenide gain medium, optically pumped by an Er:ZBLAN fiber laser. The output power of 2.1 W with 59% slope efficiency respect to absorbed pump at liquid nitrogen cooling is achieved. We show that strong re-absorption high iron ion doping concentrations leads continuous tuning central wavelength from 4012 4198 nm. robustness high-power laser combined prominent spectroscopic...
A side-pump coupler made of fluoride fibers was fabricated and tested. The tested device had a coupling efficiency 83% driven with an incident pump power up to 83.5 W, demonstrating high-power operation. Stable laser output 15 W at wavelength around 2.8 μm achieved over 1 h when using erbium-doped double-clad fiber as the active medium. To best our knowledge, this is first time fluoride-glass-fiber-based has been developed. test two devices demonstrated further scalability.
Abstract This work developed a fiber-optic refractometer taking advantage of the anomalous dispersion by water as an approach to monitoring relative humidity. The sensor part this device was fabricated mechanical polishing indium fluoride fiber capable transmitting mid-infrared radiation. found respond variations in humidity consequence rapid changes external refractive index related condensation on exposed fiber. Clear signal were also obtained response exposure human breath when using...
Ablation of expanded polytetrafluoroethylene without disruption the fine porous structure is demonstrated using an intense femtosecond-pulse laser. As a result laser-matter interactions near ablation threshold fluence, high-energy ions are emitted, which cannot be produced by thermal dissociation molecules. The ion energy Coulomb explosion elements (-CF(2)-CF(2)-)(n) and spectra show contributions from explosions rather than those expansion to generate ions. dependence on laser fluence...
Terahertz (THz) emission from argon cluster plasma, generated by intense femtosecond laser pulses in the energy range of 10–70 mJ, has been investigated. THz polarization, dependence, and angular distribution were measured to provide an initial discussion on mechanisms emission. much higher clusters than gas, which indicates that plasma produced atomic holds considerable promise as source.
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...
A fluoride-fiber-based master oscillator power amplifier (MOPA) for 30-W class continuous-wave (cw) operation at 2.8-μm wavelength has been demonstrated. To overcome the low durability of ZBLAN fibers, various novel technologies using fluoride glass with a ZBLAN-fiber-based side-pump combiner have adopted in system. maximum cw output 33 W and stable under 23-W We suggest that such fiber MOPA systems will open up advanced technology next-generation high-power mid-IR lasers.
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...
Recently, ultrashort laser processing has attracted attention for creating nitrogen-vacancy (NV) centers because this method can create single NV in spatially-controlled positions, which is an advantage quantum information devices. On the other hand, high-density a wide region also important sensing sensitivity directly enhanced by increasing number of centers. A recent study demonstrated creation irradiating femtosecond pulses, but created was limited to micrometer size, and technique...