The Review of Laser Engineering
Online ISSN : 1349-6603
Print ISSN : 0387-0200
ISSN-L : 0387-0200
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Volume 21, Issue 6
Displaying 1-8 of 8 articles from this issue
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  • [title in Japanese]
    Tadao SHIMIZU
    1993 Volume 21 Issue 6 Pages 617
    Published: June 29, 1993
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.21.6_617
    JOURNAL FREE ACCESS
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  • Blue Upconversion Fiber Laser
    Kazuyuki HIRAO
    1993 Volume 21 Issue 6 Pages 618-624
    Published: June 29, 1993
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.21.6_618
    JOURNAL FREE ACCESS
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    Some rare-earth ions, when incorporated into a suitable lattice, can upconvert infrared light into visible one. This upconversion phenomenon is attracting a great interest in the application of a blue wavelength laser excited by on infrared laser diode. Pr- or Tm-doped fluoride fiber glass is suitable for this purpose. The characteristics of these upconversion fluorescences were examined for these fiber glass in order to obtain the upconversion mechanism. An upconversion laser glass excited by the laser diode would be realized when an appropriate glass host is chosen.
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  • Experiments on Carbon Balmer-α Soft X-Ray Lasers Pumped with a 12ps KrF Laser
    K. MURAI, Y. KATO, R. KODAMA, S. NAKAI, H. SHIRAGA, G. YUAN, L. DWIVED ...
    1993 Volume 21 Issue 6 Pages 625-633
    Published: June 29, 1993
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.21.6_625
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    Carbon Balmer-α soft X-ray lasers were studied by using a KrF Raman laser system (SPRITE) at the Rutherford Appleton Laboratory in UK. The studies were carried out in collaboration of the Rutherford Appleton Laboratory and the Institute of Laser Engineering, Osaka University. Carbon fiber targets (7μm in diameter) were irradiated with a 268nm laser light at a pulse duration of 12ps, an energy of 5J and an average irradiance of 3×1014W/cm2. Time resolved Balmer-α (18.2nm) intensity from hydrogen-like carbon ions was measured with a flat-field XUV spectrometer coupled to a streak camera. The gain in the Balmer-α transition observed at 4 mrad from the target axis showed gain after 200ps from the pump laser irradiation. Experimental results were compared with a time dependent average-atomic-model coupled with a hydrodynamic code (MEDUSA102). We take into account of effects of nonuniformity of the absorption irradiance to explain small gain observed in the experiment.
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  • Truncation Coefficient Optimization for Elliptical Laser Gaussian Beams on Optical Head
    Mitsushige KONDO
    1993 Volume 21 Issue 6 Pages 634-640
    Published: June 29, 1993
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.21.6_634
    JOURNAL FREE ACCESS
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    The present paper describes a computational study of the effects of a truncation coefficient on cross talk and frequency characteristics. The effects result from direct focusing of laser diode elliptical Gaussian beams when the minor axis of a focused beam is adjusted parallel to the track. It was found that a truncation coefficient that yields the minimum cross talk level varies with track spacing. Calculations were carried out on track spacing ranging from 1 to 2μm, which is the range required for practical applications. When the space between tracks was 1.4μm; the wavelength of the laser diode, 780nm; the NA of a objective lens, 0.5; the truncation coefficient which minimized cross talk was 0.7, and the minimum cross talk level was -40 dB. The change in frequency characteristics was less than 1 dB when the truncation ranged from 0.7 to 1.0, and these values did not affect playback characteristics.
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  • Development of a Portable Lidar Using a Diode-Pumped YAG Laser
    Hiroshi OKUMURA, Tadashi SUGITA, Hironori MATSUMOTO, Shigesumi KUWASHI ...
    1993 Volume 21 Issue 6 Pages 641-648
    Published: June 29, 1993
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.21.6_641
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    An all solid-state, portable, diode-pumped YAG lidar system with a solid-state detector was constructed and demonstrated successful for the measurement of fogs. The laser is intracavity Q-switched with an acousto-optical modulator. The high repetitive pulses are detected with an avalanche photodiode and are processed with a specially designed, continuously operated signal processor without interruption of operation. The efficiency of the new processor, as well as a fog intrusion measurement, is discussed.
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  • Use of Insulated Gate Bipolar Transistors in an All Solid State Exciter for Multikilowatt Average-power, TEA CO2 Lasers
    Hidekazu HATANAKA, Katsumi MIDORIKAWA, Tsutomu TAKAHASHI, Yuichiro TER ...
    1993 Volume 21 Issue 6 Pages 649-660
    Published: June 29, 1993
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.21.6_649
    JOURNAL FREE ACCESS
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    Using insulated gate bipolar transistors (IGBT), we constructed an efficient, all solid state exciter for high efficiency, high power operation of a transversely excited atmospheric (TEA) CO2 laser. The exciter was composed of a high-voltage pulse generator and a two-stage magnetic pulse compressor. Forty-eight series and two parallel IGBTs were used as the main switch of the pulse generator. The maximum switching voltage as high as 36 kV was achieved with a transfer energy of about 100J. The pulse generator, employing an LC inversion circuit, produced a 65 kV, 7.5μs pulse, which was compressed to 0.5μs by the pulse compressor. The use of an IGBT stack decreased energy waste in a snubber circuit, resulting in a high efficiency of more than 90%. By applying the exciter to a TEA CO2 laser with a discharge volume of 0.5l, an average laser power of 4.6 kW was attained at a repetition rate of 550 pps for a switching energy of 78J. The overall efficiency of the laser was as high as 10.5%. A repetition rate of 1.1 kpps was attained, resulting in an average laser power of 3.4 kW by reducing the switching energy to 42J.
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  • A Differential SPR Biosensor with a Modulated Laser
    Xiaochun SUN, Haruo TAJIMA, Katsumi YONEDA
    1993 Volume 21 Issue 6 Pages 661-665
    Published: June 29, 1993
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.21.6_661
    JOURNAL FREE ACCESS
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    A differential detection method and a modulated semiconductor laser have been developed for a surface plasmon resonance (SPR) biosensor. By using this method, the influence of sample backgrounds, e.g., its composition or temperature, can be cancelled and immunoreactions can accurately be measured in real time. Moreover, using the modulated laser, we can diminish the influence of noise from background light and amplify output signals to a favorable level. The sensitivity of the sensor can thus be improved. Using such an SPR biosensor system, we have been able to detect α-Fetoprotein of a few ng/ml.
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  • [title in Japanese]
    1993 Volume 21 Issue 6 Pages i
    Published: June 29, 1993
    Released on J-STAGE: February 26, 2010
    DOIhttps://doi.org/10.2184/lsj.21.6_i
    JOURNAL FREE ACCESS
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