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Volume 31, Issue 5
Displaying 1-7 of 7 articles from this issue
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Topical Papers on Direct Applications of High-Power Smiconductor Lasers
Topical Papers
Laser Reviews
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Yasukazu IZAWA2003 Volume 31 Issue 5 Pages 312
Published: 2003
Released on J-STAGE: February 03, 2006
JOURNAL FREE ACCESSDownload PDF (92K) -
—Results of Research and Development in Germany—Friedrich BACHMANN, Reiji TAKAHASHI2003 Volume 31 Issue 5 Pages 313-317
Published: 2003
Released on J-STAGE: February 03, 2006
JOURNAL FREE ACCESSGreat expectations were expressed about the future of high power diode lasers for direct materials processing applications, when they have been introduced in the mid nineties. Nevertheless, based on their technology, i.e. how kilowatt power is generated from individual elements, which can provide just a few ten watts, there are also some limitations, especially if beam quality is considered. However, fortunately not all laser materials processing techniques require extremely high power density, i.e. high beam quality, but rather need a larger spot or a spot with a special shape. Such applications are the niches for the highly efficient and reliable diode lasers. In this context, high power diode lasers have proven to be a perfect supplement to the existing CO2 and Nd:YAG materials processing lasers rather than a competitor for them.View full abstractDownload PDF (1438K) -
Nobuyuki ABE2003 Volume 31 Issue 5 Pages 318-325
Published: 2003
Released on J-STAGE: February 03, 2006
JOURNAL FREE ACCESSRecently, diode lasers with high power and high power density have been developing and many researches have been reported in many application fields of materials processing. In this report, beam characteristics of high power diode lasers and the trend of materials processing with high power diode lasers are discussed.View full abstractDownload PDF (1789K) -
Masamoto TAKATSUJI, Yasuhiro MORI2003 Volume 31 Issue 5 Pages 326-329
Published: 2003
Released on J-STAGE: February 03, 2006
JOURNAL FREE ACCESSPossibility of a completely-controlled plant factory using red laser diodes and light-emitting diodes is discussed and basic experimental data concerning relative growth rate, photosynthetic rate and vitamin C contents are given for lettuces under these lights. Special attention is given for the promotion of growth per unit radiation energy under intermittent (pulsed) application of lights. Plant factories using these diodes may be materialized in near future if the price of laser diodes is reduced and suitable intermittent lights are applied.View full abstractDownload PDF (1035K) -
Takahisa JITSUNO, Kieu TOKUMURA, Hisashi TAMAMURA2003 Volume 31 Issue 5 Pages 330-336
Published: 2003
Released on J-STAGE: February 03, 2006
JOURNAL FREE ACCESSCurrent techniques developed for beam shaping of multi-mode laser diode (LD) output are reviewed and a new approach for the direct micro-processing with a single-mode LD is reported. The advantage of single-mode LD for high brightness focusing, the source of aberration in LD light, and the method to improve the brightness are described. The experiment on the laser ablative shaping (LAS) for single-mode laser light indicated that the initial wavefront distortion of 0.9 λ was improved to 0.4 λ. Possible applications of LD micro-marking system are described.View full abstractDownload PDF (1309K)
Regular Papers
Laser Originals
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Kiyoshi ISHIKAWA, Hirohiko IMAI, Yoshihiro TAKAGI2003 Volume 31 Issue 5 Pages 337-341
Published: 2003
Released on J-STAGE: February 03, 2006
JOURNAL FREE ACCESSWe have optically polarized the nuclear spin of xenon atoms using a frequency-narrowed high-power laser-diode. The free-induction signals of polarized xenon in gas and liquid phases were measured in a magnetic field of less than 3 mT. The polarized xenon plays the role of a probe atom sensitive to the local environment. For example, we could detect the atoms, selectively, on or below the surface of liquid ethanol utilizing chemical shift imaging. The free-induction signal is so large that we can track the polarized xenon atoms dissolving into liquid ethanol through its surface. We also observed the spin-polarization of protons of ethanol transferred from polarized xenon.View full abstractDownload PDF (780K) -
Real-Time Monitoring of the Surface Modification of Root Dentin Using MIR-FEL-Induced Acoustic WavesHiroyuki NAGATA, Manabu HEYA, Shu SANO, Takeyuki UCHIZONO, Yuichi HASH ...2003 Volume 31 Issue 5 Pages 342-347
Published: 2003
Released on J-STAGE: February 03, 2006
JOURNAL FREE ACCESSFor a non-invasive laser treatment, a real-time and non-contact monitoring technique is needed. We have investigated the extent of the surface modification of root dentin using photoacoustic spectroscopy (PAS), and have discussed the applicability of PAS technique to in vivo monitoring during laser treatment. Temporal behaviors of laser-induced acoustic waves were measured with an audible microphone. The extent of the surface modification, such as morphological and chemical changes, was evaluated by using information on the ablation depth and absorption spectrum of the irradiated dentins. The morphological and chemical changes of the irradiated dentin are respectively available for caries removal and increased acid resistance for root surface caries therapy. From the observations, it was found that time-resolved measurement of acoustic waves leads to a real-time understanding on the extent of the morphological change of the irradiated dentin. We have demonstrated the applicability of an in vivo monitoring technique involving PAS for root surface caries therapy.View full abstractDownload PDF (1632K)
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