A5054817470- Solid State Laser Technologies
- Luminescence Properties of Advanced Materials
- Photorefractive and Nonlinear Optics
- Glass properties and applications
- Advanced Fiber Laser Technologies
- Laser Design and Applications
- Magneto-Optical Properties and Applications
- Laser Material Processing Techniques
- Laser Applications in Dentistry and Medicine
- Quantum optics and atomic interactions
- Optical properties and cooling technologies in crystalline materials
- Nuclear materials and radiation effects
- Optical Systems and Laser Technology
- Microwave Dielectric Ceramics Synthesis
- Semiconductor Lasers and Optical Devices
- Photonic Crystals and Applications
- Random lasers and scattering media
- Advanced ceramic materials synthesis
- Radiation Detection and Scintillator Technologies
- Advanced Fiber Optic Sensors
- Ocular and Laser Science Research
- Seismic Waves and Analysis
- Optical and Acousto-Optic Technologies
- Atomic and Subatomic Physics Research
- Photonic and Optical Devices
Nagoya University
2015-2020
Japan Fine Ceramics Center
1999-2011
Institute for Molecular Science
2004-2009
National Institute for Laser Plasma and Radiation Physics
2009
Schott (Germany)
2008
Kao Corporation (Japan)
2007
Tokyo Institute of Technology
2006
KRI
2001-2003
Osaka Institute of Technology
1995-2001
Yamagata University
2000
Transparent polycrystalline YAG with nearly the same optical characteristics as those of a single crystal were fabricated by solid‐state reaction method using high‐purity powders (>99.99 wt% purity). The average grain size and relative density 1.1 at.% Nd:YAG ceramics obtained about 50 μm 99.98%, respectively. An oscillation experiment was performed on cw laser diode excitation system ceramics. experimental results indicated an threshold slope efficiency 309 mW 28%, These values...
Polycrystalline, transparent YAG (Y 3 AI 5 O 12 ) ceramics were fabricated by a solid‐state reaction method using high‐purity Al 2 and Y powders. The mixed powder compacts sintered at 1600° to 1850°C for h under vacuum. Optical transmittance in the region between ultraviolet infrared wavelengths (1 mm thick) 1800°C was similar that single crystal.
▪ Abstract Yttrium aluminum garnet (YAG) (Y 3 Al 5 O 12 ) single crystals doped with active species such as Nd and Yb have been used laser media in solid-state lasers requiring high energy excellent beam quality. This is because extremely thermal mechanical properties optical qualities they enable high-efficiency oscillation. In 1995 the authors, using polycrystalline Nd:YAG, demonstrated a that was comparable to single-crystal laser. Subsequently, single-longitudinal-mode oscillation, green...
This paper reports recent progress in the production of polycrystalline Nd:YAG (Y 3 Al 5 O 12 ), Nd:YSAG Sc 1.0 4.0 Yb:YSAG ceramics, and a Nd‐doped YAG single crystal with an almost perfect pore‐free structure by advanced ceramic processing. The laser conversion efficiency Nd‐ Yb‐doped ceramics is extremely high, their optical qualities are comparable that commercial high‐quality crystals. We have also succeeded fabrication crystal, which can be used for oscillation, solid‐state reaction...
Diode-pumped laser oscillation in highly Nd3+-doped polycrystalline Y3Al5O12 (YAG) ceramics has been demonstrated. The Nd:YAG are transparent; the loss of a 2.3 at. % neodymium-doped ceramic is as low that 0.9 single crystal. high doping Nd3+ ions realizes large pump absorption; 6.6 %-doped an absorption coefficient 60.4 cm−1 at 808 nm. same concentration quenching parameter obtained between and crystals. A using 847-μm-thick 3.4 gain medium operates times higher output power than with...
For the present study, 1.1‐at.%‐Nd‐doped YAG ceramics with controlled amounts of grain‐boundary phase were fabricated by a solid‐state reaction method using high‐purity powders. The optical scattering loss Nd:YAG ceramics, obtained from Fresnels equation, increased simply phase. continuouswave laser output power clearly was related to coefficients specimens that, in turn, affected amount Although grain‐boundary‐free structure and lower pore volume (}150 vol ppm) almost equivalent those...
Nd,Cr‐codoped transparent YAG (Y 3 Al 5 O 12 ) ceramics with excellent optical properties were fabricated by a solid‐state reaction method using 2 , Y Nd and Cr powders of 99.99 wt% purity. The mixed powder compacts sintered at 1750°C for 20 h under vacuum annealed 1400°C in an oxygen atmosphere. Nd,Crcodoped consisted grain sizes ranging from to 35 μm exhibited pore‐free structure. transmittance 0.8 at.% Nd,0.4 Cr: ceramic 1000 nm was nearly equivalent that Nd: single crystal. In addition,...
A Nd‐doped HfO 2 ‐Y O 3 ceramic having excellent transmittance was synthesized by HIPing, using high‐purity powders (>99.99 wt%) of Y , Nd and . The mixed powder compacts these were sintered at 1650°C for 1 h under vacuum HIPed 1700°C 196 MPa Ar. specimen after HIPing consisted uniform grains measuring about 30 μm pore‐free structure. optical at.% 2.6 mol% ceramics ranging between visible infrared wavelength almost equivalent or superior to that a Nd:Y single crystal grown the Verneuil method.
A neodymium‐doped yttrium‐aluminum garnet (Y 3 A1 5 O 12 , YAG) (Nd:YAG) ceramic that contained 0.3–4.8 at.% neodymium additives and exhibited nearly the same optical properties as those of a single crystal was fabricated by solid‐state reaction method using high‐purity powders. Although integrated absorption intensity 2 H 9/2 + 4 F 5/2 bands simply increased concentration in YAG ceramics decreased, fluorescence 2.4 Nd:YAG strongest among with various concentrations 0.9 crystal. An...
The authors propose an energy cycle based on a renewable fuel. Magnesium is chosen as carrier and combusted with water to retrieve using many power devices. MgO, the combustion residue, reduced back Mg by laser radiation generated from solar other sources. They have achieved recovery efficiency of 42.5% for converting MgO magnesium, laser. Combined demonstrated 38% artificial sunlight source (metal halide lamp) into output indicates that proposed already in feasible range practical use.
We have succeeded for the first time in synthesizing an optical grade (TbXY1-X)2O3 (X=0.5-1.0) ceramic Faraday rotator, which greatly exceeds basic characteristics of commercial terbium gallium garnet (TGG) (Tb3Ga5O12) crystal. The rotation angle increased as Tb concentration increased, and Verdet constant from 2.1 (82 rad T-1 m-1 at X=0.5) to 3.8 times (154 X=1.0) than TGG single crystal, is regarded highest class. Therefore, it possible minimize rotator length magnet building isolator. It...
Abstract Super full dense (Tb x Y 1− ) 3 Al 5 O 12 ( =0.5‐1.0) ceramics with optical grade (pore‐free) were successfully produced by solid‐state reaction between Tb 4 7 and 2 raw powders. Transparent sintered bodies obtained sintering at 1720°C for hours in vacuum furnace. By additional HIP treatment, scattering centers effectively removed, finally the quality of was improved to grade. Optical loss samples 1064 nm approximately 0.1%/cm, optically inhomogeneous parts not observed inside...
High-resolution optical spectroscopy shows that no additional defects or large-scale deformations take place in Nd:YAG ceramics doped with up to 9 at. % Nd as compared the diluted single crystals. Spectral satellites connected ensembles of ions, predicted by statistics a random distribution over available lattice sites, are observed at low temperatures. At higher temperatures resolution is lost and these contribute an inhomogeneous broadening lines. room temperature global emission decay...
The possibility of using the thermally activated optical absorption bands for a resonant pump in emitting level highly doped Nd laser materials is discussed. This potential demonstrated by continuous wave 1064 nm emission under 885 concentrated (up to 6.8 at. %) Nd:YAG ceramics.
We report what is believed to be the first laser operation based on Ho3+-doped Y2O3. The Ho3+:Y2O3 ceramic was resonantly diode-pumped at ~1.93 µm produce up 2.5 W of continuous wave (CW) output power ~2.12 µm. had a slope efficiency ~35% with respect absorbed and beam propagation factor M2 ~1.1. have measured absorption stimulated emission cross sections 77 K 300 present calculated gain section spectrum for different excited state inversion levels.
The spectroscopic characteristics of Dy3+ in YAG (Y3Al5O12) transparent ceramics prepared by solid state synthesis were investigated, with special attention to the visible (yellow, blue) emissions that could be pumped directly new developed blue–violet or near UV laser diodes. absorption and emission spectra, recorded at different temperatures from 10 300 K, analyzed relevant parameters, improved energy level scheme, temperature effects, intensity parameters based on Judd-Ofelt theory...
High‐quality 10%Yb: YAG ceramics was successfully synthesized without sintering additives such as SiO 2 for the first time. Optical scattering loss of Yb: 0.1%/cm and its transmitted wavefront distortion λ/19.5 ( t = 4.7 mm), which very comparable to single crystal laser materials. Laser performance thin disk made this material (φ11 × 0.15 mm) 74.1% slope efficiency (optical‐to‐optical conversion efficiency: 68.1%) maximum output power reached 1.8 kW. Synthesis high‐purity high‐quality using...
Abstract Fully dense and infrared transparent YIG (Y 3 Fe 5 O 12 ) ceramics was successfully produced by solid‐state reaction of Y 2 powders. Its relative density reached 99.8% (5.16 g/cm after sintered at 1400°C for hours, almost 100% (5.17 obtained additional HIP treatment. It wavelength ranges longer than 1100 nm, its in‐line transmittance (ca. 75%‐77%) very comparable to that commercial single crystal especially over 1700 nm. Faraday rotation angle 1300 1550 nm 224 175 deg/cm,...