A5058685651- Laser Material Processing Techniques
- Spectroscopy and Laser Applications
- Laser-induced spectroscopy and plasma
- Atmospheric and Environmental Gas Dynamics
- Spectroscopy Techniques in Biomedical and Chemical Research
- Advanced Optical Sensing Technologies
- Semiconductor Lasers and Optical Devices
- Laser Design and Applications
- Atmospheric aerosols and clouds
- Ocular and Laser Science Research
- Laser-Plasma Interactions and Diagnostics
- Power Transformer Diagnostics and Insulation
- Spectroscopy and Chemometric Analyses
- Laser-Matter Interactions and Applications
- Atmospheric chemistry and aerosols
- Advanced Fiber Laser Technologies
- Water Quality Monitoring and Analysis
- Mass Spectrometry Techniques and Applications
- Advanced X-ray Imaging Techniques
- Surface Roughness and Optical Measurements
- Adhesion, Friction, and Surface Interactions
- Ion-surface interactions and analysis
- Petroleum Processing and Analysis
- Surface Modification and Superhydrophobicity
- Terahertz technology and applications
Institute for Laser Technology
2015-2025
Osaka University
2014-2025
Laser-Tech (Czechia)
2019
Kindai University
2010-2016
Nanospectra Biosciences (United States)
2016
Tohoku University
2013
Industrial Technology Center of Okayama Prefecture
2010
Osaka Health Science University
2007
The concentration of furfural in transformer oils is a well known indicator for decomposition insulating paper. Using laser Raman spectroscopy, we performed detection experiments dissolved without complex and time consuming preprocessing procedures. Furfural was characterized by signal at ~1707 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , where no spectral interferences caused oil-derived signals occur. results show that...
Nanowire arrays—vertically aligned metal wires with a few hundred nanometers in diameter—are promising nano-structured targets for high-energy-density physics and related applications. We have been developing ultrafast, time-resolved measurements on laser-irradiated using the x-ray free electron laser at SACLA facility. Here, we present fabrication of various kinds nanowire array order to explore absorption mechanism ultrahigh intensity irradiation, their application laser-irradiation...
We have developed a laser Raman spectroscopy technique for assessing the working conditions of transformers by measuring dissolved C2H2 gas concentrations present in transformer oils. A frequency doubled Q-switched Nd:YAG (532 nm) was used as source, and signals at ~1972 cm(-1) originating from oil were detected. The results show that is useful alternative method detecting faults.
As the use of CFRP material becomes widespread in various industries, achieving high-speed cutting with less pulse energy and minimal thermal damage is one important issues for laser-based processing. Among parameters laser processing, we have focused on wavelength from UV (266 nm) to NIR (1064 pulsewidths 100 fs 20 ns order investigate efficiency terms ablated mass per irradiated corresponding heat affected zone (HAZ). Samples used our experiments were uni-directional CFRPs thickness 140 μm...
Ablative Rayleigh-Taylor instability growth was investigated to elucidate the fundamental physics of thermal conduction suppression in a magnetic field. Experiments found that unstable modulation is faster an external This result reproduced by magnetohydrodynamic simulation based on Braginskii model electron transport. An field reduces across lines because Larmor radius electrons much shorter than temperature scale length. Thermal leads spatially nonuniform pressure and reduced ablative...
A simple approach to generate high energy, frequency and bandwidth tunable multicycle THz pulses by optical rectification (OR) of spatially shaped femtosecond laser in the lithium niobate (LN) crystal is proposed demonstrated. one dimensional binary shadow mask used as a beam shaper. By building mask's image bulk LN with various demagnifications, generation was tuned range 0.3 - 1.2 THz. There exist also an opportunity tune from 20 GHz approximately 1 changing size on crystal. The energy...
We demonstrated the first range-resolved detection and identification of CO2 dissolved in water by Raman lidar. A frequency doubled Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (532 nm) is used as lidar light source, signals at ∼1273 ∼1380 cm-1 from were detected. In application, was identified glass bottles 20 m away using band cm-1.
We have been investigating material processing of CFRP with short pulse lasers in order to control mechanical and thermal damages. While ultra-short laser pulses enable us process the without damages, machining speed tends be slow due limited average power system. Hence, we focus our attention on micromachining sub- mm thick CFRP. Considering excellent properties carbon fibers, has potentials replace metals would useful for innovative devices electronics industries. Micromachining thin...
The temperature dependence of the laser-induced damage threshold on optical coatings was studied in detail for laser pulses from 123 K to 473 at different temperature. For longer than a few picoseconds, coated substrates increased with decreasing This reversed shorter picoseconds. We describe physics models explain observed scaling. electron avalanche is essential differences dependence.
A strong quasistationary magnetic field is generated in hollow targets with curved internal surface under the action of a relativistically intense picosecond laser pulse. Experimental data evidence formation strongly magnetized plasma structures decaying on hundred picoseconds timescale, strength kilotesla scale. Numerical simulations unravel importance transient processes during generation and suggest existence fast slow regimes plasmoid evolution depending interaction parameters. The...
<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Conventional ground-penetrating radar (GPR) requires large-aperture antennas or long-span measurements to survey a remote location precisely. We propose laser-driven GPR (LGPR) as new detection method. LGPR uses microwaves from laser-produced plasmas transmitters and can using compact instrument. performed numerical simulations investigate the radiation mechanism of laser confirmed pulsewidth...
We built a differential optical absorption spectroscopy system to measure near-surface CO2 in the atmosphere using nanosecond white light continuum. The laser can cover wavelengths ranging from 420 2400 nm, where and H2O lines are located. At an path length of 568 m, it was possible evaluate atmospheric concentration bands vicinity 2000 nm detected by broadband simultaneously.
We describe a portable Raman lidar system that can remotely detect oil leakages in water. The has been developed based on frequency-doubled, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>Q</mml:mi> </mml:math> -switched Nd:YAG laser, operated at 532 nm with receiver telescope equipped some filters and photomultipliers. Stand-off detection of is achieved 6-m-long water tank, which allowed us to considerably increase the survey capability subsea...
We report on the hard-target reflection spectroscopy of carbon monoxide (CO) gas based technique infrared tunable diode laser absorption aiming at developing a low-cost yet sensitive sensor for early detection spontaneous coal combustion. A narrow-band distributed feedback emitting around 2333.7 nm is used to monitor CO molecules contained in 5 cm cell. The light diffusely backscattered from surface lump placed end 50 path detected with photodiode coaxial transmitter/receiver setup. From...
A white light continuum was generated by focusing the terawatt 800 nm femtosecond laser pulse in Kr gas. The spectrum spanned a broad wavelength range from 300 to more than 2200 nm. used for first time perform direct absorption spectroscopy of CO2 at around 2000 laboratory cell. present system can be measuring concentrations with an accuracy 1–2 ppm (ca. 0.5%) atmosphere 5.5 km propagation lengths through air.
Abstract Femtosecond double-pulse laser induced breakdown spectroscopy (LIBS) has been performed with a configuration composed of two polarizers. The effect interpulse separation on the Cu I line at 510.55, 515.32, and 521.82 nm showed an optimum enhancement 50–150 ps delays, which is more than 3–5 times greater compared single-pulse excitation case. This enhanced emission may open new possibilities for remote LIBS detection.
Lidar (light detection and ranging) depolarization measurements were performed simultaneously at three wavelengths using a coherent white light continuum. The continuum ranging from the ultraviolet to infrared region was generated by focused 0.5 TW/100 fs pulse in krypton gas cell atmospheric pressure. lidar system consisted of channels 450, 550, 800 nm. observed ratios for each wavelength showed differences clouds. These features are discussed terms particle size shape T-matrix...
Wafer-bonding-based integration can be rapidly and easily tested between different types of devices by wafer-to-wafer flip-chip transfer technology described in this paper. Devices to (e.g. MEMS) on a support wafer are bonded electrically connected with target LSI) using sticky silicone bumps, then any the selectively debonded from backside laser irradiation. After transferred, device is temporary sealed ring, underfill polymer used for permanent bonding. Because bonding made just physical...
We put forward a co-axial pump (optical)-probe (x-rays) experimental concept and show performance of the optical component. A Bessel beam generator with central 100 µm diameter hole (on axis) was fabricated using femtosecond (fs) laser structuring inside silica plate. This flat-axicon element produces needle-like axial intensity distribution which can be used for pulse. The fs-x-ray free electron (X-FEL) sub-1 introduced through along axis onto target as probe. Different realisations are...
We examined the applicability of Raman lidar technique as a laser remote sensing tool in water. The has already been used successfully for measurements CO2 gas dissolved water and bubbles. Here, effect seawater on spectra evaluated. A frequency doubled Q-switched Nd:YAG (532 nm) was irradiated to standard seawater. In seawater, signals at 984 1060-1180 cm-1 from SO42- were detected, which shows no spectral interference caused by derived CO2.
We carried out depolarization light detection and ranging (LIDAR) measurements for the first time using a coherent white continuum with multi-wavelength backscatter measurements. The from UV to IR region was generated in Kr gas by terawatt femtosecond laser system. LIDAR system consisted of channel at 450 nm five-wavelength Mie scattering channels 350, 450, 550, 700, 800 nm. This technique can potentially open promising avenue toward simultaneous multi-wavelength.
We performed a lidar observation of Asian dust aerosols for the first time using white light system. The used in utilized coherent continuum generated Kr gas as source and was three-wavelength Mie-scattering having depolarization measurement capability at 450, 550, 800 nm. Lidar ratios 0.30–0.70 nm were measured. These data reveal higher ratio than usual (normally almost zero) lower troposphere. Thus, can identify particles that pose threat to cross-border pollution Japan.