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1987 Volume 15 Issue 6 Pages
324-327
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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Koichi SHIMODA
1987 Volume 15 Issue 6 Pages
328-331
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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Different aspects of coherence are discussed. The coherence function which describes mutual correlationof the light cannot fully represent the temporal and spatial characteristics of the laser.
Theoretical and experimental studies of the linewidth of the gas laser and the semiconductor laser are reviewed. Novel methods of reducing the laser linewidth are in progress.
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Tadashi KANABE, Masahiro NAKATSUKA
1987 Volume 15 Issue 6 Pages
332-341
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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The present status of high power solid-state laser technology for the inertial confinement fusion and otherapplications are described. The developments of new laser material, diode laser pumping and slab geometries arekey technologies for achieving high average power and high efficiency. The direction of the future developmentin large scale solid-state laser system for ICF is also described.
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Kenichi UEDA
1987 Volume 15 Issue 6 Pages
342-346
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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The scalability of electron beam pumped Kr F laser amplifier has beendiscussed as a typical example of ultra high power gas lasers. Energy depletion due to the amplified spontaneous emission is the final limitingfactor for the large scale Kr F laser amplifier. According to the scaling law of the amplified spontaneous emission, the experimental simulation of 1/1000 model has been demonstrated by using 500J Kr F laser with modularelectron beam diodes. The 500J Kr F laserat high pumping rate of 1MW/cc made it sure that the largevolume Kr F laser at low pumping rate of 100k W/cc will provide 500k J with high intrinsic efficiency above10%. Large scale Kr F laser is the most promising high power laser for fusion reactors.
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Yasuharu SUEMATSU, Shigehisa ARAI
1987 Volume 15 Issue 6 Pages
347-352
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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High power semiconductor lasers are reviewed and summarized from the aspects of power conversionefficiency and power limit available for the cavity structure. For high power operation of semiconductor laser, power conversion efficiency from electrical to optical power is very important. The guidelines to obtain highquantum efficiency are summarized and discussed.
Maximum output power of around 200m W/facet is available both for 0.85μm Al Ga As/Ga As and 1.3μm Ga In As P/In P lasers with sophisticated structures. For high-power application, phaselocked array laser is one of most promising device which can emit CW output of several watts.
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Takuzo SATO, Kenzo MIYAZAKI
1987 Volume 15 Issue 6 Pages
353-358
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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A review of the present status of research on the generation of coherent VUV andsoft X-ray radiation is presented. In the last 15 years many techniques have been developed by utilizing third-and higher-order nonlinear processes to generate coherent radiation in the spectral region below 200 nm. The shortest wavelength of the coherent radiation generated so far is 14.6 nm, which is the 17th harmonic of an intense picosecond Kr F laser (248 nm) output, and the continuousliy tunable coherent radiation has been successfully generated down to about 70 nm. Further development of the nonlinear frequency conversion technique may extend the spectral region of useful coherent radiation to the XUV and X-ray.
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The Present Status and Future Problems
Mikio YAMASHITA
1987 Volume 15 Issue 6 Pages
359-364
Published: June 28, 1987
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The present status of ultrashort-pulse lasers and pulse-compression techniques in the femtosecond-time region is reviewed. In addition, the future problems to be solved for generation of shorter pulses are described.
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Toshiharu TAKO, Yoshiaki AKIMOTO
1987 Volume 15 Issue 6 Pages
365-369
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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Development and recent progress of laser frquency control of gas, dye, and semiconductor lasers are reviewed. Narrowing of laser spectral width, stabilization of the center frequency and freqency tuning with high frequency stability are described. Ultrahigh frequency stabilties of 3×10
-16 for a He-Ne laser and 10
-14-10
-15 for an Al Ga As laser has been realized. In these cases “phase stable” laser is more appropriate than “frequency stable” laser after J. L. Hall.
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Yoshiaki KATO
1987 Volume 15 Issue 6 Pages
370-374
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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Signficant progress has been made recently toward realizing coherentemission in XUV region. Amplification of XUV radiations in 10.2-18.2 nm have been observed at ILE, Osaka University. Recent progresses at ILE and other laboratories are briefly reviewed.
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Kunioki MIMA
1987 Volume 15 Issue 6 Pages
375-380
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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Concepts and historical review of free electron laser are reported. Since the experiment at Stanford University was successful in 1977, great numberof FEL experiments with various accelerators were successfully performed to observe amplification and oscillation of radiations in the wavelength range of 0.5 μm-10
3μm. As for shorter wavelength FELs, various ideas have been proposed and some experimental facilities in XUV and soft X-ray spectral rangewill be completed near future to begin oscillation experiments.
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Tatsuo YAJIMA
1987 Volume 15 Issue 6 Pages
381-384
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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Present status and future prospects of lasers in fundamental science are brieflyreviewed. With emphasis on physical science, several subjects such as, roles of laser spectroscopy, significance of extreme conditions in both lasers and materials, challenges to fundamental laws and fundamental phenomena, nature of light, are discussed.
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Tetsuro KOBAYASHI
1987 Volume 15 Issue 6 Pages
385-391
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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Recent advances in ultra-high-speed opto-electronic devices are reviewed and compared with those in high-speed all-electronic devices. In addition, coming ultrafast electronics, “subpicosecond-terahertz electronics” which will be established by utilizing high-speed optical electronics, is forecast.
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Kazuo KYUMA
1987 Volume 15 Issue 6 Pages
392-396
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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In this paper, the laser sensing technologies towards the twenty-first century are discussed. They are classifiedinto the following four topics: (1) practical fiber-optic interferometicsensors, (2) distributed and pointsensor-multiplexed fiber-optic sensors, (3) parallel sensing technologies, and (4) detection technologies for ultraweak light and sensing technologies using ultra short optical pulses.It is also emphasized that the further developments of new class of optical components such as integratedoptics, optoelectronic integrated circuits and functional optical fibers are requrired for the sophisticatedlaser sensing systems described above.
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Tadashi SUETA
1987 Volume 15 Issue 6 Pages
397-400
Published: June 28, 1987
Released on J-STAGE: July 30, 2010
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Lightwave communication has been developed extensively in these years. One of the potentialities of thelightwave is its high-speed or broad-band property. Present communication system, however, utilizes only partsof this feature. The possibility of higher-speed systems, several or even several tens gigabits per second, is discussed.
Another interesting development towards next century is the repeater-less long-haul transmission. The key element is the ultra-low-loss infrared fiber with one-to-two order small attenuation constant compared with ordinary silica fiber.
Finally, lightwave transmission through outer space, e. g. inter-satellite link, is described. In this case, short wavelength of the lightwave yields the extremely sharp light beam with the radiator much smaller than the radio-wave antenna.
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Hiroshi NISHIHARA
1987 Volume 15 Issue 6 Pages
401-405
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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Future development of laser information processing machines such as optical discs players, optical cardssystems and laser printers is described. Optical disc systems will be more developed for the coming years since information processing of larger capacity will be required. Improvement of optical recording systems can be achieved by higher density recording techniques, integration of optical head and development of new recording materials.
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Yoshiki ICHIOKA
1987 Volume 15 Issue 6 Pages
406-412
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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This paper describes the present state and the prospect of optical computers. Areas of system architectures of optical parallel computers are emphasized and breakthroughs required in the development of optical computers are indicated. In addition, the role of the optical computer in a hybrid computing system in future is discussed.
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Thermal Processing
Tadashi TAKAHASHI
1987 Volume 15 Issue 6 Pages
413-419
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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The present status of thermal material processing using lasers is reviewed. Laser material processing has become an indispensable tool for fast, precise and specialized processing operations in the manufacturing industry. The features of laser material processing and some examples of industrial applications are described.
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Role of Excimer Lasers
Koichi TOYODA
1987 Volume 15 Issue 6 Pages
420-423
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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Rapid growth of laser photochemical processings including lithography, and CVD as well as other new surface modification techniques have suggested the realization of new material techniques using short wavelength lasers.
The excimer lasers will have a central role in this development. The short wavelengths of excimer lasers contribute to satisfy the requirement of local attachment of specific materials or removal in a single step process which increases the importance in future. The short pulse durations of excimer lasers make it possible to create new non-equilibrium materials having new compositions and new microsturctures which are not obtained normally.
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Yasukazu IZAWA
1987 Volume 15 Issue 6 Pages
424-429
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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Laser isotope separation is in the engineering development stage following 10 years of systematic studies of selective excitation process and separation scheme. Recent advances of hydrogen and uranium isotope separation by lasers are reviewed.
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Uichi KUBO
1987 Volume 15 Issue 6 Pages
430-435
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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Medical application of lasers has been rapidly progressive and has become an important field in laser application. The instruments (CO
2 laser scalpel ete.) availing thermal effects have been mainly developed so far. Recently, with the advance of laser techniques, short wavelength lasers are developed and could be put topractical use. The photochemical effects have attracted much interest in medicine and new surgical treatmentsare expected using ultraviolet lasers, tunable lasers, etc.. In this paper, the features and future prospects ofmedical lasers are interpreted.
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Takashi KUSHIDA
1987 Volume 15 Issue 6 Pages
436-440
Published: June 28, 1987
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Various applications of lasers in the field of biological sciences are reviewed briefly. It is shown that remarkable features of laser beams, such as high degree of coherence, high monochomaticity and directionality, good focusability, high intensity and high electric field at the focused sopt, ultrashort pulse duration and so on, are utilized to the fullest in these applications. Examples to employ lasers in Raman and fluorescence spectroscopy, ultrafast spectroscopy, light scattering, laser microscopy, selective excitation, flow cytometry, microsergery, etc. are presented.
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Sadao NAKAI
1987 Volume 15 Issue 6 Pages
441-446
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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The progress of laser fusion is remarkable approaching to the breakeven condition, in which the fusiongenerated energy is compalable to the incident laser energy onto the fuel pellet.
The investigation on the absption of laser light, energy transport, ablation and impiosion hydrodynamicsof a pellet are proceeded leading to the accumulation of the date bases which are necessary for the scalingto the fusion ignition and breakeven. The recent results of the neutron generation of 10
13 per shot and the pelletgain of O.2% by LHART demonstrate the feasibility to achieve the ignition condition with 100kJ blue laser.
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Tatsutoku HONDA
1987 Volume 15 Issue 6 Pages
447-454
Published: June 28, 1987
Released on J-STAGE: February 26, 2010
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The optoelectronics industry is expected to be one of the leading industries in the 21st century. Exten-sive growth in the optoelectronics industry has been sustained by recent advances in laser and optical fiber technologies, such as fiber-optic communications, optical disks, laser printers, laser processing systems and others.
The 1986 total production value was \1040 billion, an increase of 22% over 1985. Of this total, that con-cerned with optical devices such as laser and optical fiber totaled \370 billion, equipment and facility related production, such as laser processing, fiber communication and optical memory accounted for \543 billion and optical application systems, such as fiber communications, figured \127 billion. At present there is a growth in companies offering optoelectronic application devices and systems. The current state of optoelectronics indus-try in Japan will be surveyed for three technological areas: communication, information handling and energy application.
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