The Review of Laser Engineering
Online ISSN : 1349-6603
Print ISSN : 0387-0200
ISSN-L : 0387-0200
Volume 17, Issue 2
Displaying 1-9 of 9 articles from this issue
  • Hiroshi TAKUMA
    1989 Volume 17 Issue 2 Pages 69-70
    Published: February 28, 1989
    Released on J-STAGE: March 17, 2010
    JOURNAL FREE ACCESS
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  • Kazuo IMASAKI, Tatsuhiko YAMANAKA, Kunioki MIMA, Sadao NAKAI, Chiyoe Y ...
    1989 Volume 17 Issue 2 Pages 71-91
    Published: February 28, 1989
    Released on J-STAGE: March 17, 2010
    JOURNAL FREE ACCESS
    In this paper, we review and discuss feasibility of free election laser (FEL) foran energydriver of inertial confinement fusion. We report super high current accelerator for a source ofelectron beam. A conceptual design of total system is described. We also briefly report a status of FEL.
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  • Minoru WATANABE
    1989 Volume 17 Issue 2 Pages 92-101
    Published: February 28, 1989
    Released on J-STAGE: March 17, 2010
    JOURNAL FREE ACCESS
    Two kinds of optical fibers have been developed for 1.55 μm long-haul systems. One is adispersion-shifted fiber and the other is a pure-silica core single mode fiber. The former will beused for high-capacity systems and the latter for long repeater-length systems. Fluoride glass fibershave the potential for achieving extremely long repeater-length if many technological obstacleswere overcome. Another future issue in optical fiber fabrication is the reduction of optical fibercosts. The higher production rate is needed to bring fibers to subscriber loop systems.
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  • Kiichiro KAGAWA, Katsushi AOKI, Naohiko SASAKI, Isamu HATTORI, Sadahir ...
    1989 Volume 17 Issue 2 Pages 102-112
    Published: February 28, 1989
    Released on J-STAGE: March 17, 2010
    JOURNAL FREE ACCESS
    A simple and rapid photoelectric detection method that can be used for spectrochemicalanalysis of microareas is presented. By scanning the wavelength of a monochromator (10 Å/min) under successive production of plasma by repeated irradiation of N2 laser light (5Hz), an emissionspectrum can be easily displayed in a short time on a personal computer.
    The characteristics of the laser plasma such as temperature was found to remain almost constantwithin at least 200 shots, though the spreading of the plasma shrinks and simultaneously theintensity of emission lines decreases with laser shots. By using standard samples of carbon steeland glass of known contents, a good linear relationship was realized between the analytical emissionline intensity and the content. The practical application to mineralogy is also discussed.
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  • Fumihiko KANNARI
    1989 Volume 17 Issue 2 Pages 113-127
    Published: February 28, 1989
    Released on J-STAGE: March 17, 2010
    JOURNAL FREE ACCESS
    Properties of the picosecond pulse amplification in a multiatmosphere CO2 laser are studiedby numerical solutions of the Maxwell-Bloch equations. The coherent effects on theshort pulsepropagation originated from the discreate structure of the vibrational-rotational spectrum of a CO2 molecule are described in detail. The characteristics of amplifier gain, saturation, and pulseshape depend on the degree of matching of a pulse spectrum with a gain spectrum. At relativelylow pressures, a train of pulses is created in a small-signal gain regime. Effective small-signalgains and effective saturation energies are obtained for various gas pressures by fitting the Frantz-Nodvik equation to the results of the model. Isotope mixtures of CO2 are also discussed to obtaina continuous gain spectrum at relatively low gas-pressures.
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  • Yutaka MATSUMI, Takashi YAGI, Hideki SAITO, Tomoo FUJIOKA
    1989 Volume 17 Issue 2 Pages 128-135
    Published: February 28, 1989
    Released on J-STAGE: March 17, 2010
    JOURNAL FREE ACCESS
    A beam quality measurement system for excimer lasers is developed. This system provides a 2-dimensional intensity distribution of an individual laser pulse delivered from an excimer laseroperated at a repetition rate of 250 Hz. The system is equipped with a large storage capacity of aframe memory which makes it possible to analyze the variation in intensity profiles of may successivepulses. The system is also equipped with the optics for measurements of far and near fieldpatterns and etalon fringe patterns. The beam qualities of a commercial excimer laser which hasan injection locking type configuration and practically measured with this system. The far andnear field patterns of a single laser pulse are presented. The pulse-to-pulse fluctuations of intensitypatterns and of total pulse energy are observed at various gas ages. The center of gravity ofsuccessive laser pulse patterns are traced with this system and the fluctuation of beam pointing isshown to increase with the gas aging.
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  • Experiments on Radicals Relevant to Carbon Film Deposition
    Tatsuo OKADA, Yoshio KAJIYAMA, Hiroyuki ANDOU, Yoshio MORIYAMA, Toshin ...
    1989 Volume 17 Issue 2 Pages 136-147
    Published: February 28, 1989
    Released on J-STAGE: March 17, 2010
    JOURNAL FREE ACCESS
    A laser spectroscopic diagnostic system was developed to measure fundamental processes inthe gas-phase of laser-induced chemical vapour deposition. The system was used to detect theradicals relevant to carbon film deposition processes, such as CH, C2, CH3 and H. Detailedmeasurements of temporal and spatial behavior of C2 radical densities were performed. Measuredresults were used to determine the reaction and the diffusion coefficients of C2 radical. The possibility of measuring the sticking coefficient on a substrate was also discussed.
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  • A Proposal of an Application of a Neural Network for Inverse Problems
    Pu QING, Shinzo KITAMURA
    1989 Volume 17 Issue 2 Pages 148-157
    Published: February 28, 1989
    Released on J-STAGE: March 17, 2010
    JOURNAL FREE ACCESS
    In this paper, we propose an application of a neural network to solve the Fredhol integralequation of the first kind to yield an aerosol size distribution from multi-wavelength laser radarmeasurements. The neural network reproduces the aerosol size distribution function or its parametersfrom the aerosol volume extinction and back scattering coefficents in the laser radar equation.We used two wavelengths data (λ1=0.53μm, λ2=1.06μm) of a Nd: YAG laser for thesimulation studies. The neural network of three layers was used in two stages. The first stage isfor the classification of the type of aerosol and the second one is for the identification of a distributionfunction or parameters. Both cases were studied by simulation, and the results showedthe success in reconstructing the distribution functions under the existence of measurement errors. The effect of the initial setting for the coefficients of the neural network and that of averaging theresults from different networks were also examined.
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  • 1989 Volume 17 Issue 2 Pages plate1
    Published: February 28, 1989
    Released on J-STAGE: March 17, 2010
    JOURNAL FREE ACCESS
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