The Review of Laser Engineering
Online ISSN : 1349-6603
Print ISSN : 0387-0200
ISSN-L : 0387-0200
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Volume 27, Issue 3
Displaying 1-15 of 15 articles from this issue
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  • [title in Japanese]
    Kunihiko WASHIO
    1999 Volume 27 Issue 3 Pages 149
    Published: March 15, 1999
    Released on J-STAGE: March 17, 2010
    DOIhttps://doi.org/10.2184/lsj.27.149
    JOURNAL FREE ACCESS
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  • On the Topical Papers of Guiding Technology for High Power and High Energy Lasers
    Mitsunobu MIYAGI
    1999 Volume 27 Issue 3 Pages 150
    Published: March 15, 1999
    Released on J-STAGE: March 17, 2010
    DOIhttps://doi.org/10.2184/lsj.27.150
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  • Nd: YAG Laser Power Transmission through an Optical Fiber
    Hirotaka KANAZAWA
    1999 Volume 27 Issue 3 Pages 151-155
    Published: March 15, 1999
    Released on J-STAGE: March 17, 2010
    DOIhttps://doi.org/10.2184/lsj.27.151
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    This article describes characteristics of Nd: YAG lasers and the technologies of beam delivery through flexible optical fibers. The spread of the industrial YAG laser market has been accelerated by the enhancement of laser power and by the utilization of flexible optical fibers for beam delivery. New methods of bothbeam division and beam addition are developed by using fiber beam delivery technologies . Fiber power transmission enables the use of high power YAG lasers for new applications in extremely severe environments such asthe interior. of thin pipes or underwater.
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  • CO2 Lasers for Material Processing and the Optical Transmission Technology
    Haruhiko NAGAI
    1999 Volume 27 Issue 3 Pages 156-160
    Published: March 15, 1999
    Released on J-STAGE: March 17, 2010
    DOIhttps://doi.org/10.2184/lsj.27.156
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    Configurations and optical resonators of CW and pulsed CO2 lasers are reviewed together with their output characteristics. Characteristics of a laser beam and a propagating gaussian beam are also reviewed theoretically, and the optical transmission technologies for a CO2 laser beam are described.
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  • Optical Energy Transmission from High-Power Laser Diodes
    Satoshi YAMAGUCHI
    1999 Volume 27 Issue 3 Pages 161-166
    Published: March 15, 1999
    Released on J-STAGE: March 17, 2010
    DOIhttps://doi.org/10.2184/lsj.27.161
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    Collimation techniques for high-power laser diode emission are surveyed . Lens ducts, fiber bundles, lens arrays, prism arrays, step-minors, two-mirrors, and diffractive optical elements have been presented so far. Phase-locked 2-dimensional laser diode arrays and monolithic arrays of optical elements, whichcollimate the emissions, will play an important part in future laser technology.
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  • Recent Advances in IR-Transmitting Fibers for Laser Power Delivery
    Toshiharu YAMASHITA
    1999 Volume 27 Issue 3 Pages 167-172
    Published: March 15, 1999
    Released on J-STAGE: March 17, 2010
    DOIhttps://doi.org/10.2184/lsj.27.167
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    Recent advances in IR-transmitting crystalline and glass fibers for laser power delivery are reviewed with emphasis on AlF3-based fluoride glass and chalcogenide glass fibers . The AlF3-based fluoride glass fiber with a high damage threshold exceeding 8 MW/cm2 input power density has for over 2 years been an important component of an Er: YAG dental laser system, offering flexible and stable, long-term transmission of high laser power. A high damage threshold of 200 kW/cm2 has been achieved in the As-S chalcogenide glass fiber, which is useful for CO laser power delivery. The power-handling capability of the As-S fiber far exceeds that attainable with the Ge-Se-Te chalcogenide glass fiber, which suffered thermal damage with CO2 laser powerdensity of only 40 kW/cm2. Fur crystalline fibers, AgClBr polycrystalline and sapphire single crystal fibers are commercially available for power delivery of the CO2 laser and the Er: YAG laser, respectively .
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  • [title in Japanese]
    1999 Volume 27 Issue 3 Pages 172-172,184
    Published: March 15, 1999
    Released on J-STAGE: March 17, 2010
    DOIhttps://doi.org/10.2184/lsj.27.172
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  • Hollow Fibers for Laser Delivery Systems
    Yuji MATSUURA, Mitsunobu MIYAGI
    1999 Volume 27 Issue 3 Pages 173-177
    Published: March 15, 1999
    Released on J-STAGE: August 25, 2010
    DOIhttps://doi.org/10.2184/lsj.27.173
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    Hollow fibers for variety of lasers emitting wavelengths from the infrared to ultraviolet are introduced. Forinfrared lasers represented by CO2 and Er: YAG lasers, hollow fibers having dielectric and silver film on theinside of glass tubing have been developed. It is shown that the fibers transmit high-powered laser light withlow attenuation due to the interference effect of the internal dielectric layer. For excimer laser light, hollow glassfibers with an inner aluminum film show low loss characteristics because of the high reflection coefficient ofaluminum in the ultraviolet region. Hollow fibers enable many applications in industrial and medical fieldsthat need effective delivery medium of laser light.
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  • Medical Applications of Fiber-Based Optical Power Delivery
    Shunichi SATO, Tsunenori ARAI
    1999 Volume 27 Issue 3 Pages 178-184
    Published: March 15, 1999
    Released on J-STAGE: March 17, 2010
    DOIhttps://doi.org/10.2184/lsj.27.178
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    This paper reviews the current status of fiber-based optical power delivery for medicine and its applications to minimally invasive therapeutics and diagnostics. Quartz glass fibers, hollow fibers, and infrared glass/crystalline fibers are used for the power transmission of medical lasers. The characteristics of these fibers and fiber-based medical laser devices are described. For clinical applications, fibers are used in combinationwith catheters, endoscopes, or cannulas. Catheter-based applications include laser angioplasty, laser thrombolysis, and PTMR (Percutaneous Trans-Myocardial Revascularization). The endoscope allows the delivery of optical power not only for coagulation but also for tissue removal (ablation). Endoscopes for PDT (PhotoDynamic Therapy) are also developed. For cannula-based applications, PLDD (Percutaneous Laser Disk Decompression), ILCP (Interstitial Laser Coagulation of Prostate), and TUBAL-T (TransUrethral Balloon Thermotherapy) are described. For use in fiber-based optical biopsies, the principle and apparatus of a fluorescence imagingsystem for early cancer detection and an OCT (Optical Coherence Tomography) are introduced.
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  • Calculation of Ion Abundance of Collisional X-Ray Lasers Using Thin Foil Targets
    Akira SASAKI, Takayuki UTSUMI, Kengo MORIBAYASHI, Toshiki TAJIMA, Hiro ...
    1999 Volume 27 Issue 3 Pages 185-189
    Published: March 15, 1999
    Released on J-STAGE: March 17, 2010
    DOIhttps://doi.org/10.2184/lsj.27.185
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    This study describes an efficacious setup for producing lasing plasma which utilizes a thin solid film for the purpose of collisional x-ray lasers. For analyzing this setup, a simple atomic kinetic model of multiple charged high Z ions is developed. The model based on screened hydrogenic approximation is improved to reproduce a level structure of Ar-like to Pd-like ions. The time dependent ion abundance is calculated in plasmas produced from a thin foil irradiated by a short pulse laser. Calculations show the optimum heating pulse duration for attaining a large abundance of Ni-like ions in the expanding plasma. Combined with excitation by the second short pulse laser, this plasma can be an effective medium for producing a transient gain of electron-collisional excited x-ray lasers.
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  • Characteristics of Lidar Signal Using Silicon Avalanche Photodiode Single Photon-Counting Module
    Kenji TATSUMI, Tadashi IMAI
    1999 Volume 27 Issue 3 Pages 190-193
    Published: March 15, 1999
    Released on J-STAGE: August 04, 2010
    DOIhttps://doi.org/10.2184/lsj.27.190
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    This paper reports the characteristics of 1μm lidar signal using Silicon Avalanche Photodiode (Si-APD) single photon-counting module. The transmitter of the lidar is a laser diode pumped Q-switched Nd: YAG laser with the wavelength of 1064 nm. The beam divergence is 0.5 mrad. The diameter of the receiver telescope is 300 mm and the field of view is 0.7 mrad. The receiver employs a photon-counting-solid state Geiger mode Si-APD module whose model number is SPCM-AQ-212 which was made by EG&G, Canada. The atmospheric observations were performed using the lidar at Tsukuba Space Center in November 7, 1997. It was very clear day and there was not a speck of cloud in the sky. Experimental results show that the distribution of received photo-electron signal from the atmosphere is a near Poisson's distribution, and signal-to-noise ratio increases proportional to the square root of accumulation.
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  • Detection of Trace Molecules in the Atmosphere by Nonlinear Raman Spectroscopy without a Tunable Laser
    Noriyuki KAWADA, Yuji OKI, Junya TAKAFUJI, Mitsuo MAEDA
    1999 Volume 27 Issue 3 Pages 194-198
    Published: March 15, 1999
    Released on J-STAGE: March 17, 2010
    DOIhttps://doi.org/10.2184/lsj.27.194
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    A new technique for nonlinear Raman spectroscopy is proposed and discussed theoretically in terms of the detection of gas molecules in atmospheric pressure. In the proposed scheme, only a pulsed Nd: YAG laser is used as a pumping source, and instead of a tunable laser, a Raman shifter filled with the sametype of gas as that to be detected automatically generates the Raman shifted radiation. The detection limits of H2for SRGS (Stimulated Raman Gain Spectroscopy), PARS (Photo-Acoustic Raman Spectroscopy), and CARS (Coherent Anti-Stokes Raman Spectroscopy) are demonstrated experimentally, and the ppm order detection limit can be achieved by PARS. Although the sensitivity of CARS is smaller than that of PARS, the signal tonoise ratio in higher concentration is more effective.
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  • Visualization of Atmospheric Structure in Nagano City for Urban Planning Using Lidar Measurement
    Yasunori SAITO, Yasuhiro KUBOTA, Takaaki NISHIOKA, Fumitoshi KOBAYASHI ...
    1999 Volume 27 Issue 3 Pages 199-203
    Published: March 15, 1999
    Released on J-STAGE: March 17, 2010
    DOIhttps://doi.org/10.2184/lsj.27.199
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    Atmospheric aerosol observations in Nagano city were performed using a scanning-type lidar system and the results were visualized as two-dimensional horizontal or vertical cross-sections . On the horizontal image, an area of high aerosol density clearly appeared along a main road with heavy traffic . The originof the aerosol was exhaust from vehicles. Differences in the vertical aerosol structure between winter and summer were shown, and these differences were discussed in relation to urbanization, human activities and regional weather conditions. These results show that the visualized data can offer rare and important information for urban planning and its environmental assessment, and also that the lidar measurement technique has great potentials in this field.
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  • Performance Comparison of Room-Temperature CO and CO2 Lasers, Used with the Same Apparatus
    Kouki SHIMIZU, Shunichi SATO
    1999 Volume 27 Issue 3 Pages 204-209
    Published: March 15, 1999
    Released on J-STAGE: March 17, 2010
    DOIhttps://doi.org/10.2184/lsj.27.204
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    Output performance and beam characteristics have beencompared between room-temperature, rf-dischargeexcited CO and CO2 lasers, used with the same apparatus. When switching the operating laser type, cavity mirrors and gas mixtures were replaced. Under optimized conditions, output powers of 340W and 380W were obtained with the CO and the CO2 lasers, respectively. With the CO laser, a much higher slope efficiency (28%) was achieved (slope efficiency with the CO2 laser was 20%), suggesting that a much higher operating efficiency at higher inputs was obtainable for the CO laser. It was also confirmed, experimentally and theoreticall, that for the higher-ordered Gaussian mode beams, the divergence angles of the CO and CO2 lasers were comparable for the given laser cavities with the same diameter and length. For the fundamental Gaussian mode, however, a lower divergence angle, and hence, a more highly focusable beam, can be obtained with the CO laser than with the CO2 laser.
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  • Fundamentals of Nonlinear Optics III: Non-Perturbative Effects and Others
    Tatsuo YAJIMA
    1999 Volume 27 Issue 3 Pages 210-217
    Published: March 15, 1999
    Released on J-STAGE: March 17, 2010
    DOIhttps://doi.org/10.2184/lsj.27.210
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