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Sadao NAKAI
1998 Volume 26 Issue 2 Pages
141
Published: February 15, 1998
Released on J-STAGE: August 25, 2010
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Kazuyoshi ITOH
1998 Volume 26 Issue 2 Pages
142-143
Published: February 15, 1998
Released on J-STAGE: August 25, 2010
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Osamu MATOBA, Tsutomu SHIMURA, Kazuo KURODA
1998 Volume 26 Issue 2 Pages
144-149
Published: February 15, 1998
Released on J-STAGE: August 25, 2010
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Optical three-dimensional waveguides can be fabricated by scanning a focused laserbeam into a photorefractive material. Fabricated waveguide structure can be modified by its guided beam. Thesewaveguides can be used as adaptive interconnections for the opticalearning neural network system. We introduce the techniques for fabricating the waveguides with uniform and nonuniform structures and an array of the waveguides in undoped and iron-doped lithium niobate crystals. Experimental results of guiding tests andmeasurements of the refractive-index distributions of fabricated waveguides are presented. We also present optical dynamic characteristics of the waveguide caused by the guided beam.
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Kiyotaka MIURA, Kazuyuki HIRAO
1998 Volume 26 Issue 2 Pages
150-154
Published: February 15, 1998
Released on J-STAGE: August 25, 2010
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In an attempt to write optical waveguides in bulk glasses, photo-induced refractive index changes were continuously created by focusing an ultra-short pulse laser through a microscope objective and translating the sample parallel or perpendicular to the axis of the laser beam. The resulting linear refractive index changes were written inside the bulk glasses along the path traversed by the focal point of the laser. From field intensity distributions in the output of guided light for these waveguides, we demonstrated that permanent optical waveguides could be successfully formed in various types of glass.
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Akira YABE, Hiroyuki NIINO
1998 Volume 26 Issue 2 Pages
155-160
Published: February 15, 1998
Released on J-STAGE: August 25, 2010
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Formation of microstructures on surfaces of polymer materials by excimer laser irradiation is reviewed from the viewpoint of morphological surface modification. Although the microstructures is not explained by a simple model, the factors controlling the shape and size of microstructures are discussedon the basis of SEM micrographs of polymer surfaces. In addition it is shown that the microstructure formedby excimer laser ablation of acrylate rubber containing carbon black has a visco-elastic property which is interesting in tribological control. Finally the applications of microsctures on polymer materials are described.
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Masahiro UEDA, Mugen KAWAZU, Jing CHEN, Keiji TANIGUCHI, Katsuhiko ASA ...
1998 Volume 26 Issue 2 Pages
161-163
Published: February 15, 1998
Released on J-STAGE: August 25, 2010
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A cloth weft densitometer has been proposed and its propriety verified by a preliminary experiment. The method is based on the counting of cloth wefts by a CCD camera with a shutter speed of 1 ms. The experiment shows that the densitometer can be used perfectly for many types of cloth if the cloth speed of less than approximately 10 m/min. The accuracy of the cloth-weft counting is above 99%, provided that the image contrast of the weft on the CCD camera is sufficiently high. Only 2-step digitation by the A/D converter is needed for 99% accuracy.
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Hiroki YOSHIDA, Tomonori MIZUTANI, Yukio SAKAGAMI
1998 Volume 26 Issue 2 Pages
164-167
Published: February 15, 1998
Released on J-STAGE: August 25, 2010
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To use laser ablation for the removal of thin film without substrate-damage, we must decide suitable laser conditions which must be determined by the removed thickness-laser pulse width-laser intensity. We present a simple model based on heat transport which can provide the effective graph. We perfom the 30 ps-single pulse Nd: YAG laser irradiation with various laser intensities. The targets were used of 62.6-82.3 nm thick Ni coated on glass plane substrates. The irradiated surfaces of them are observed by an optical microscope, a scanning electron microscope, and a multiple beam interferometer. We find the suitable laser conditions in vacuum to be 6 × 10
12-9 × 10
12Wm
-2-2 × 10
2-3 × 10
2Jm
-2-3 × 10
-4-5 × 10
-4J, which correspond with the model.
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Hitoshi NAKANO, Takeyoshi NAKAYAMA, Uichi KUBO
1998 Volume 26 Issue 2 Pages
168-171
Published: February 15, 1998
Released on J-STAGE: August 25, 2010
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The mechanism associated with excimer laser ablation of hard tissue has been studied using fast photography and an electron probe micro analyzer (EPMA). A bovine femur was adopted as a modelof hard tissue. The ArF and KrF excimer lasers were used in this study. Time-resolved photographs of ablation plume were obtained using a microscope-mounted camera together with pulsed illumination from a XeCl excimer laser pumped dye solution. Ablation velocity and the start time of ablation were estimated. In addition, change in composition of bone surface was investigated by EPMA. The ratio of Calcium to Phosphor, which is an important parameter for determining the chemical characteristics of Hydroxyapatite, was estimated. Possible mechanisms to explain laser ablation were examined. The results indicated that theArF and KrF excimer lasers promoted primarily photothermal ablation. Photochemical ablation had occurred only in ArF excimer laser irradiation. Photomechanical ablation appeared to be negligible during ArF and KrF excimer laser ablation of bone.
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Hiroyuki FURUKAWA, S.I. ANISIMOV, Katsunobu NISHIHARA, Kazuo IMASAKI, ...
1998 Volume 26 Issue 2 Pages
172-175
Published: February 15, 1998
Released on J-STAGE: August 25, 2010
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Theoretical estimations on laser cleanings have been performed by simulations. Basic equations are the equation of thermal conduction, the absorption of laser energy, boundary conditions of melting and evaporation. Simulations have been performed for the case of 2-layers, basic material is SUS304 and surface pollutant is Fe
3O
4. Simulation results were in good agreements with experiments at the wide range of irradiated laser energy densities.
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Jing CHEN, YeongEun LEE, Keiji TANIGUCHI, Katsuhiko ASADA, Masahiro UE ...
1998 Volume 26 Issue 2 Pages
176-178
Published: February 15, 1998
Released on J-STAGE: August 25, 2010
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An optical method for measuring the mean diameter of glass wool fiber is proposed and discussed from the viewpoint of practical use. The method uses both light scattering and light reflection off glass wool.The method can measure mean fiber diameters in the area illuminated by laser light in real time.
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Huitian WANG, Jiasen ZHANG, Shin YOSHIKADO, Tadashi ARUGA
1998 Volume 26 Issue 2 Pages
179-181
Published: February 15, 1998
Released on J-STAGE: August 25, 2010
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We investigated and explain herein the dependence of the fidelity of the reconstructed output images on the position of the distorting medium for one-way image transmission through a thin distorting medium by using the wave-front reversal advantage of four-wave mixing phase conjugation ina photorefractive crystal.
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Naoyoshi KAMISUGI, Nobu KUZUU, Yoshinao IHARA, Takayuki NAKAMURA
1998 Volume 26 Issue 2 Pages
182-185
Published: February 15, 1998
Released on J-STAGE: November 29, 2010
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Characteristics of KrF-excimer-laser induced absorption in synthetic fusedsilica were investigated. The intensities of induced absorption depend not only on the OH content, but also on the internal absorption at 200 nm. Excimer laser-resistive optical materials can be obtained by using a fused silica containing more than approximately 1000 ppm of OH, with an internal absorption at 200 nm of less than 0.015 cm
-1.
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Mitsuo MAEDA
1998 Volume 26 Issue 2 Pages
186-194
Published: February 15, 1998
Released on J-STAGE: August 25, 2010
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for Development of Methods to Cool and Trap Atoms with Laser Light
Masayoshi WATANABE
1998 Volume 26 Issue 2 Pages
195-198
Published: February 15, 1998
Released on J-STAGE: August 25, 2010
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