The Review of Laser Engineering
Online ISSN : 1349-6603
Print ISSN : 0387-0200
ISSN-L : 0387-0200
Volume 26, Issue 12
Displaying 1-13 of 13 articles from this issue
  • Hiroyoshi YAMAGAMI
    1998 Volume 26 Issue 12 Pages 839
    Published: December 15, 1998
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
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  • Takao KOBAYASHI
    1998 Volume 26 Issue 12 Pages 840
    Published: December 15, 1998
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
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  • JohnJ ZAYHOWSKI
    1998 Volume 26 Issue 12 Pages 841-846
    Published: December 15, 1998
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    Passively Q-switched Nd: YAG microchip lasers are robust, compact, economical, all-solid-state sources of coherent, subnanosecond, multikilowatt pulses at high repetition rates. These diminutive, quasi-monolithic devices produce pulses as short as 218 ps, pulse energies up to 250μJ, and peak powers up to 565 kW. The high output intensities enable the construction of extremely compact nonlinear optical systems. The short pulses are useful for high-precision ranging using time-of-flight techniques. The short pulse durations and ideal mode properties can also be used to advantage in the characterization of materials. When focused, the output intensities are sufficient to photoablate materials, with applications in laser-induced breakdown spectroscopy and micromachining. The ultraviolet harmonics of the microchip laser have been used to perform fluorescence spectroscopy for a variety of applications. Systems based on the passively Q-switched microchip lasers, like the lasers themselves, are small, efficient, robust, and potentially low cost, making them ideally suited for field use.
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  • Takunori TAIRA
    1998 Volume 26 Issue 12 Pages 847-854
    Published: December 15, 1998
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    Recent developments in microchip solid-state lasers are introduced. A diode laser is used as an excitation source to pump a solid-state “chip” of approximately a few mm3 in size to convert the poor spatial and spectral mode output of the diode laser into a spectrally and spatially pure, low-noise beam. In addition, remarkable progress on pulsed operation, including Q-switching or mode-locking, and nonlinear wavelength conversion through the use of microchip laser is described. The feasibility of each compact optical device is briefly discussed.
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  • Kenju OTSUKA
    1998 Volume 26 Issue 12 Pages 855-860
    Published: December 15, 1998
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    The material synthesis of stoichiometric (direct compound) solid-state laser crystal LiNdP4O12 (LNP), which includes Nd atoms as its composition elements, and the early-stage demonstration of the laser-diode-pumped LNP laser are described. Peculiar lasing properties such as simultaneous multitransition oscillations and high-density pumping effects, which result from the inherent high Nd-density, complex dynamics featuring self-organization in multimode oscillations, and the possible application to ultrahigh-sensitivity sensing that effectively utilizes a microcavity configuration are reviewed.
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  • Akinori HARADA, Yoji OKAZAKI, Koji KAMIYAMA
    1998 Volume 26 Issue 12 Pages 861-866
    Published: December 15, 1998
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    A quasi-phasematched second harmonic generation device with a periodically poled crystal is one of the most attractive methods for realizing high-quality visible lasers. We have recently newly developed a blue and green laser diode-pumped intracavity frequency doubling solid-state lasers through the use of periodically poled bulk MgO-LiNbO3. The periodically poled MgO-LiNbO3 with uniform periodicity was successfully obtained by a novel corona discharge method. The larger temperature-acceptance bandwidth of the periodically poled bulk MgO-LiNbO3 made it possible to realize the simultaneous temperature control of the laser diode and of the solid-state laser cavity. In addition, the stable single axial mode operation in the solid-state laser was accomplished by using an etalon. As a result, our new blue and green solid-state laser is compact, has high-stability laser power, low noise operation, and high beam quality. By using these blue and green solid-state lasers, a new digital photo-printing system and a new fluorescent image analyzer were realized.
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  • Deyuan SHEN, Jie SONG, Kenichi UEDA
    1998 Volume 26 Issue 12 Pages 867-870
    Published: December 15, 1998
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    In this paper, we report the results of analytical and experimental studies of the characteristics of a high-brightness laser-diode end-pumped Nd: YVO4/KTP laser. A simple model was developed to optimize the cavity parameters and to estimate the green output power of intracavity-frequency-doubled lasers. Using a 1-W high-brightness laser-diode as the pump source, high-efficiency operation was realized based on the optimized cavity design. The second-harmonic output power at 532 nm was measured to be 286.5 mW at an incident pump power of 881.4 mW, corresponding to an optical-to-optical efficiency of 32.5 %.
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  • Masaharu HYODO, Masahiko TANI, Noriaki ONODERA, Kiyomi SAKAI
    1998 Volume 26 Issue 12 Pages 871-875
    Published: December 15, 1998
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    The generation of narrow-band millimeter-wave radiation has been achieved by photomixing two longitudinal modes in a two-mode microchip laser. The two modes were frequency-converted to their second harmonics using an external cavity, then focused onto the photoconductive gap of an LTG-GaAs photomixer . A millimeter wave was generated from the photoconductive antenna and examined using a spectrum analyzer with a millimeter-wave mixer. The linewidth observed for the millimeter wave was 430 Hz at 101 GHz, which is only 1/230 the width of the individual laser modes. This narrow linewidth of the millimeter wave can be attributed to the cancellation of most of the frequency fluctuations embedded in the two modes due to their sharing the same volume in the same cavity.
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  • Kimio ASAKA, Yoshihito HIRANO, Yukihiro MORIMOTO, Kumio KASAHARA
    1998 Volume 26 Issue 12 Pages 876-880
    Published: December 15, 1998
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    A coherent lidar is an attractive sensor for atmospheric observation because it can measure wind velocity even in clear air conditions. In this paper, a coherent lidar is presented which uses a microchip laser for a seed and a local source made of Er, Yb: Glass. The microchip Er, Yb: Glass laser module is oscillated at 1.53μm that is, an eye-safe wavelength, and a single frequency output of 16.4 mW is obtained. The injection-seeding diodepumped Er, Yb: Glass laser is side-pumped by two 5-stacked LD arrays. Laser medium size is 1.2×1.2×10 mm. The injection-seeding pulse output of 2.5 mJ is obtained with a repetition rate of 20 Hz and a pumping power of 240 mJ. A detection distance of 800 m is achieved with the S/N ratio over 10.
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  • Atsushi UCHIDA, Takeshi OGAWA, Takahiro SATO, Fumihiko KANNARI
    1998 Volume 26 Issue 12 Pages 881-886
    Published: December 15, 1998
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    We demonstrate control and synchronization of chaos in a Nd: YVO4 microchip laser. Stabilization of chaotic oscillations to high periodic orbits is experimentally and numerically accomplished by internal frequency resonance between the pump and loss modulation frequencies. Various periodic patterns can be extracted predictably from one chaotic oscillation by varing the pump modulation parameters. Characteristics of synchronization of chaos in two separate Nd: YVO4 microchip lasers are also analyzed in the case of employing two master-slave types and a mutually-coupled type. A secure optical communication system using chaos synchronization is numerically demonstrated.
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  • Koichiro NAKAMURA, Hiromasa ITO
    1998 Volume 26 Issue 12 Pages 887-891
    Published: December 15, 1998
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    In a frequency-shifted feedback (FSF) laser, an intracavity light field is frequency-shifted beforebeingrecirculated through a gain medium. The FSF operation is obtained by placing an acousto-optic modulator inside the cavity and closing the cavity by the first order diffracted light of the modulator. The intracavity frequency shift prevents an evolution of a standing wave in the cavity and the laser output exhibits a very unique spectral feature. In this paper, the spectral output of the FSF laser is examined by use of a diode-pumped Nd: YVO4 as a gain medium. A theoretical treatment of the FSF behavior is also discussed. It is shown here that the FSF laser output has spectral output called “chirped frequency comb” with an ultrafast frequency chirp rate of several hundreds of PHz/s.
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  • Sadao UEMURA, Michael HENTSCHEL, Christian SPIELMANN, Ferenc KRAUSZ
    1998 Volume 26 Issue 12 Pages 892-894
    Published: December 15, 1998
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    We characterize 25-fs pulses from a Ti: sapphire multipass amplifier system using the high-dynamic-range third-harmonic-generation autocorrelation technique, which enables us toobserve the asymmetry of amplified pulses. We have succeeded in suppressing the background on the leading edge using positive-third-orderdispersion chirped mirrors.
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  • Free Electron Laser (Tunable Laser)
    Kazuo IMASAKI, Sadao NAKAI
    1998 Volume 26 Issue 12 Pages 895-898
    Published: December 15, 1998
    Released on J-STAGE: August 25, 2010
    JOURNAL FREE ACCESS
    Download PDF (792K)
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