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25 巻, 4 号
選択された号の論文の12件中1～12を表示しています
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三間 圀興1997 年 25 巻 4 号 p. 265
発行日: 1997/04/15
公開日: 2010/02/26
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豊田 浩一1997 年 25 巻 4 号 p. 266
発行日: 1997/04/15
公開日: 2010/02/26
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J. Thomas DICKINSON, David R. ERMER, Jaw-Jung SHIN, Stephen C. LANGFOR ...1997 年 25 巻 4 号 p. 267-277
発行日: 1997/04/15
公開日: 2010/02/26
ジャーナル フリーIn applications of high intensity lasers to materials processing, the formation of an ablation plume is of high importance. For wide bandgap insulators (e.g., oxides, halides, nitrides, carbides) irradiated with sub bandgap photon energies, the route to plume formation is not well understood. For example, contrary to metals and semiconductors, inverse bremsstrahlung (IB) is not possible for a wide range of laser intensities on these materials due to insufficient photon and electron densities. We present an alternative path to plume formation on nominally transparent materials. We first examine the interaction of photo-and thermally-emitted particles from exposure to pulsed laser irradiation of surfaces which include photoelectrons, energetic positive ions, and neutral metal atoms. We establish experimentally that there is overlap in space and time of significant portions of the distributions of these particles in the near surface region. We present a model for the collective motion of these particles and show that as laser fluence is increased we achieve sufficient densities, overlap, and kinetic energies to result in the onset of plume fluorescence and eventually ionization at fluences far below any IB or catastrophic breakdown process.抄録全体を表示PDF形式でダウンロード (2483K) -
鯉沼 秀臣, 大西 剛, 神田 直樹1997 年 25 巻 4 号 p. 278-282
発行日: 1997/04/15
公開日: 2010/02/26
ジャーナル フリーThe advantages of pulsed laser deposition for oxide film growth and of molecular beam epitaxy for 2-dimensional film growth have been combined to develop a method for atomically controlled epitaxy of oxide thin films and heterojunctions. Molecular layer epitaxy has been verified by the clear observation of RHEED intensity oscillations for the growths of various oxides with perovskite, infinite-layer, rock salt, corundum, and fluorite structures. Epitaxial growth of BaO and sapphire films was achieved even at such a low temperature as 20°C. New structures with exotic properties were revealed in SrTiO3/SrVO3 superlattice, infinite-layer cuprates, and ZnO hexagonal platelets film. In view of the versatility and structure-sensitive properties of oxides, this lattice engineering technology by laser MBE is expected to open a new field of oxide electronics.抄録全体を表示PDF形式でダウンロード (1053K) -
杉岡 幸次, 和田 智之, 田代 英夫, 豊田 浩一1997 年 25 巻 4 号 p. 283-287
発行日: 1997/04/15
公開日: 2010/02/26
ジャーナル フリーMaterial ablation using vacuum-ultraviolet (VUV) lasers is reviewed. High photon energy of VUV beam accomplishs clean ablation of transparent materials in the UV region such as polytetrafluoroethylene (PTFE) and fused silica with little thermal effect. A novel ablation scheme using multiwavelength excitation by coupling of VUV and UV laser beams is also presented. In this process, the VUV beams have two important roles, that is, photodecomposition of constituent atoms (stationary effect) and formation of excited state (transitional effect), although their energy is too small to ablate materials by themselves. The multiwavelength ablation provides great potential for high-quality microfabrication of wide band-gap materials such as fused silica, crystal quartz, sapphire, lithium niobate and SiC.抄録全体を表示PDF形式でダウンロード (1229K) -
古谷 浩志, 福村 裕史, 増原 宏1997 年 25 巻 4 号 p. 288-295
発行日: 1997/04/15
公開日: 2010/02/26
ジャーナル フリーA nanosecond interferometric technique and its applications for the clarification of laser ablation dynamics are reviewed, and the morphological dynamics of the irradiated polymer films during or just after the excitation laser pulse is described. Since the nanosecond interferometric technique is based on the Michelson interferometer combined with a Q-switched Nd3+:YAG laser, expansion and contraction of the irradiated films about 20-30nm can be resolved with a time resolution of -10 ns. It is clarified that morphological dynamics of polymer films with different chemical and physical properties show a different morphological behavior depending on their chemical and physical properties upon laser ablation. On the basis of the revealed expansion and etching dynamics, ablation mechanism is discussed.抄録全体を表示PDF形式でダウンロード (1756K) -
小海 文夫, 斉藤 公続, 山本 和弘, 中村 拳子, 古賀 義紀1997 年 25 巻 4 号 p. 296-300
発行日: 1997/04/15
公開日: 2010/02/26
ジャーナル フリーOptical emission spectroscopic studies were carried out on ablation plumes produced by laser ablation of graphite at 266nm and 1064nm in vacuum and in nitrogen gas atmosphere with or without a magnetic field of -0.1 T. In vacuum, in the presence of the magnetic field, the intensity distribution of C, C+, and C2+ emission lines were varied remarkably and some of the emission lines originated from relatively higher excited states became obscure. In addition, C2 Swan band emission appeared particularly during 1064nm laser ablation. These changes in emission spectra are interpreted by promotion of ionization of C and C+, formation of C2, and deexcitation of electronically excited states, resulting from enhanced collisions between ablated species due to cyclotron motions under the magnetic field. In nitrogen gas atmosphere, enhanced N2 emission (2nd positive system) was observed and explained by electron-impact excitation of N2 molecules.抄録全体を表示PDF形式でダウンロード (875K) -
高橋 勉, 杉岡 幸次, 豊田 浩一1997 年 25 巻 4 号 p. 301-305
発行日: 1997/04/15
公開日: 2010/02/26
ジャーナル フリーA micro-magnetic divice consisting of patterned Sr-ferrite by excimer laser ablation is described. By using a projection-patterned etching, the etched pattern of 80μm in depth is achieved in focused laser irradiation (600mJ/cm2, 10Hz, 45 minutes) in air. The magnetic properties for aspect ratio and profile of laser etched grooves are calculated by a three dimensional magnetic field analysis. Furthermore, the magnetic flux density onto the Sr-ferrite substrate is also measured by magneto-optical sensor.抄録全体を表示PDF形式でダウンロード (1031K) -
細田 昌宏, 古谷 浩志, 福村 裕史, 増原 宏, 西井 正信, 一ノ瀬 暢之, 河西 俊一1997 年 25 巻 4 号 p. 306-311
発行日: 1997/04/15
公開日: 2010/02/26
ジャーナル フリーLaser ablation dynamics of amorphous film of a Cu-phthalocyanine derivative was studied by using nanosecond interferometry, nanosecond photography, space- and time-resolved absorption spectroscopy, and atomic force microscope (AFM). At 140mJ/cm2, etching of the film was found to begin at the early half of an excimer laser pulse followed by the ejection of gaseous compounds. Since the absorption spectrum of ejected materials was similar to that of the amorphous film, main molecular specie of the ejected materials is the Cu-phthalocyanine derivative, meaning no decomposition even upon laser ablation. It is suggested that photothermal mechanism is responsible for the ablation. It was observed with AFM that surface structure of the PMMA film adhered with ejected materials was covered with humps whose minimum dimension was about 120nm. It is suggested that Cu-phthalocyanine derivative was ejected not as single molecules but as submicron particles upon laser ablation.抄録全体を表示PDF形式でダウンロード (1692K) -
丸谷 洋二, 紙谷 卓之1997 年 25 巻 4 号 p. 312-315
発行日: 1997/04/15
公開日: 2010/02/26
ジャーナル フリーIn conventional stereolithography methods, the solidified photopolymer layers are stacked one by one in resin. As a result, these methods have such disadvantages as time consumption to recoat new resin layer and to remove the surface roughness caused by steps on the models. This paper proposes a new method of fabricating 3-D models in a resin. An air bubble is formed at the end of a pipe under the surface of the resin. A laser beam is introduced through the bubble so as to solidify the resin on the bubble surface. As the solidified parts have no mechanical interference with the pipe, it is free to move the exposing point in the 3-dimensional space. The resolution and sensitibity of the method were measured, and some objects were fabricated. Through these experiments, the possibility of making 3-D models without processes of lamination and recoating was demonstrated.抄録全体を表示PDF形式でダウンロード (651K) -
岡田 和之, 椿原 啓, 坂本 昭彦, 中塚 正大1997 年 25 巻 4 号 p. 316-319
発行日: 1997/04/15
公開日: 2010/02/26
ジャーナル フリーHe-Ne laser propagation in silica fiber after delivery of KrF excimer laser was experimentally investigated. The intensity at the outer part of deliveried He-Ne laser beam after delivery of KrF excimer laser was observed to be extremely reduced in comparison with that before delivery of KrF laser. We consider that this reduction results from the absorption of skew rays and/or the refractive index change at the outer part of core silica. It is supposed that these changes of optical property originate from the KrF-laser-induced defects located at the outer part of core layer.抄録全体を表示PDF形式でダウンロード (572K) -
光は波か粒子か霜田 光一1997 年 25 巻 4 号 p. 320-323
発行日: 1997/04/15
公開日: 2010/02/26
ジャーナル フリーPDF形式でダウンロード (599K)
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