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Hiroyoshi YAJIMA
1999 Volume 27 Issue 10 Pages
663
Published: October 15, 1999
Released on J-STAGE: March 17, 2010
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Kenichi MATSUNO
1999 Volume 27 Issue 10 Pages
664
Published: October 15, 1999
Released on J-STAGE: March 17, 2010
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Kozo YASUDA, Mikio MURO
1999 Volume 27 Issue 10 Pages
665-669
Published: October 15, 1999
Released on J-STAGE: March 17, 2010
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High power CO
2 lasers with an output power up to 45 kW are available for the heavy industries with thick material welding today. These systems offer a comparatively low beam quality with high price and operating costs. On the contrary a flexible high power laser welding system up to 6 kW with optical fiber like Nd: YAG laser becomes possible using for heavy industries. The use of a high power Nd:YAG laser can lead to better material processing for the thick section. For the thick material high performance welding arerequired but there are sometimes difficulty to remove the welding defect. This paper reviews laser processing for high performance welding and shows the results of research for a defect free welding system which is carried out in the
Advanced Photon Processing and Measurement Technology Project.
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1999 Volume 27 Issue 10 Pages
669-669,681
Published: October 15, 1999
Released on J-STAGE: March 17, 2010
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Takehito YOSHIDA, Eiichi OZAWA, Hirofumi SHIMURA
1999 Volume 27 Issue 10 Pages
670-675
Published: October 15, 1999
Released on J-STAGE: March 17, 2010
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We describe main features of ultrafine particles for the functional materials/devices and of physical vapor processing excited by a pulsed laser. Silicon ultrafine particles have been synthesized using the pulsed laser ablation in inert background gases. We have investigated the influence of the inert background gas pressures on transition from amorphous thin films to ultrafine particles. Furthermore, it has been clarified that there is a processing window of the inert background gas pressure in which the quantum confinement effects for carriers and phonons become apparent. Dual beam pulsed laser evaporation in inert background gases has been adopted for the synthesis of tungsten ultrafine particles. The ultrafine particles have been characterized with regard to crystal structures and agglomeration phenomena. Finally, we show results of size distribution measurements of the tungsten ultrafine particles in the formation fields by using a low pressure operating differential mobility analyzer.
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Toshitsugu UEDA, Yasunori OKAMOTO, Satoshi NAGAI
1999 Volume 27 Issue 10 Pages
676-681
Published: October 15, 1999
Released on J-STAGE: March 17, 2010
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In situ measurements in semiconductor manufacturing with lasers are advantageous in that they cause very little disturbance to objects and allow real-time accurate quantification. This paper reviews three
in situ measuring methods for gas concentration, particle identification, and wafer temperature based on IR absorption, laser induced breakdown (LIB) and laser ultrasound generation in solids, respectively.
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Shigeki HAYASHI, Hiroyuki SUZUKI
1999 Volume 27 Issue 10 Pages
682-687
Published: October 15, 1999
Released on J-STAGE: March 17, 2010
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In a photoelectron spectroscopy system, we have measured the spectra and the source diameter of laserinduced plasma soft x-rays. Furthermore, we have developed a TOF-XPS (Time of Flight-X-ray Photoelectron Spectroscopy) measuring system and obtained TOF-spectra with the x-rays. In an internal material measurement, we have developed a hard x-ray (below the wavelength of 0.1 nm) system, by focusing sub-nano second Nd: YAG laser pulses on a target supplying positive high voltage. We have also developed a DT (Digital Tomography) measuring system and obtained CT (Computed Tomography) and DT images with a micro-focus x-ray tube. In a high-sensitivity detection technology, we are developing technology for measuring the surface or sub-surface composition with high sensitivity by measuring photons (fluorescent x-rays) using a high energy-resolution superconducting x-ray detecting system.
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Masao SATO, Shinya NAITO, Nobuaki IEHISA, Norio KARUBE, Yasuhiro AKIYA ...
1999 Volume 27 Issue 10 Pages
688-693
Published: October 15, 1999
Released on J-STAGE: March 17, 2010
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Advanced photon processing and measurement technology project was started from 1997 and high power allsolid-state lasers have been developed by FANUC and Toshiba aimed to realize finally the output power of more than 10 kW with the conversion efficiency of more than 20%, with the laser head volume of smaller than 0.05m
3. So far, FANUC has obtained 3.3 kW output power with the optical efficiency of 35% using one slabtype Nd: YAG crystal. Toshiba has also obtained 3.3 kW output power with the same optical efficiency using rod-type Nd: YAG crystals. We present the detail of our development results and discuss the issue which may appear in applying high power all-solid-state laser in industries.
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Yoshihiko MATSUOKA, Hiroshi SEKIGUCHI, Hirofumi KAN, Kenichi UEDA
1999 Volume 27 Issue 10 Pages
694-698
Published: October 15, 1999
Released on J-STAGE: March 17, 2010
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Kilowatt-class fiber lasers are reviewed. From the early days, fiber lasers have been studied to make use of the high pump intensity resulting from light confinement in the fiber core. In a conventional fiber laser, the pump light is coupled through the fiber core end section. This section is too small to launch a high power diode pump beam. This limits the output power to several tens of mW. The double-clad structure allows us to increase the output power by several orders of magnitude but it can hardly exceed of a few tens of W. A new concept called “fiber embedded fiber laser” or“free shape laser” will again increase the maximum output power, making kW fiber lasers a reality. In this paper, this new concept is presented and compared with usual fiber laser technology.
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Tetsuo KOJIMA, Susumu KONNO, Shuichi FUJIKAWA, Koji YASUI
1999 Volume 27 Issue 10 Pages
699-702
Published: October 15, 1999
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Recent progress in all-solid-state UV lasers is reviewed. In all-solid-state UV lasers, frequency conversion technique is generally used. CLBO (CsLiB
6O
10) crystals are mostly used in fourth harmonic generation of solid-state lasers, since the crystal had been discovered. By use of a CLBO crystal, fourth harmonic UV power of 20.5 W was reported by an all-solid-state UV laser this year.
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Xiaoming DOU, Yukihiro OZAKI
1999 Volume 27 Issue 10 Pages
703-707
Published: October 15, 1999
Released on J-STAGE: March 17, 2010
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Dynamic enhanced vibrational spectroscopy in the near field such as surface-enhanced Raman scattering (SERS) and surface-enhanced infrared absorption (SEIRA) has recently received keen interest because it shows extremely high sensitivity in the observation of vibrational spectra of molecules. Studies of dynamic enhanced vibrational spectroscopy are of particular importance from the points of applications as well as basic science. A few groups succeeded in the single molecule detection by SERS, stimulating further possibilities of the applications of dynamic enhanced vibrational spectroscopy. The purpose of this review is to provide brief description of dynamic enhanced vibrational spectroscopy in the near field and to introduce our recent studies which aim at the elucidation of the mechanism of the surface enhancement.
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Takayuki KAMITANI, Osamu YAMADA, Yoji MARUTANI
1999 Volume 27 Issue 10 Pages
708-711
Published: October 15, 1999
Released on J-STAGE: March 17, 2010
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In this paper, we propose a new method of fabricating 3-D models of the inorganic materials having high melting points such as ceramics and intermetallic compounds by laser scanning. To save the laser energy, we adopted the combustion synthesis which is the exothermic reaction between the raw materials. By adding chemical reaction heat to laser heat, the particles of the products of the reaction were bonded together by relatively low laser energy. The combinations of the raw materials and the laser scanning conditions for solidifying the products of the reaction and laminating the solidified layers were investigated experimentally. By mixing the powdered binder with the reactive raw materials, the simple layered models were fabricated.
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Hiroki SAITO, Tetsuo KANO, Haruo UCHIYAMA, Masanori JYUMONJI
1999 Volume 27 Issue 10 Pages
712-714
Published: October 15, 1999
Released on J-STAGE: March 17, 2010
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Since dye lasers are very widely tunable from near ultra-violet to near infrared, they have been used in high resolution spectroscopy and many other tunable laser applications. Usually, dye lasers are pumped by onephoton excitation process with shorter wavelength light source compared with laser output wavelength. In this paper, we propose a new excitation method of dye by two-photon process, and also would like to report a numerical calculation of two-photon absorption cross section, as well as a demonstration of laser oscillation by two-photon excitation.
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Toshimitsu ASAKURA, Toshiaki IWAI, Yoshihisa AIZU
1999 Volume 27 Issue 10 Pages
715-718
Published: October 15, 1999
Released on J-STAGE: March 17, 2010
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