レーザー研究
Online ISSN : 1349-6603
Print ISSN : 0387-0200
ISSN-L : 0387-0200
40 巻, 2 号
「液中レーザープロセッシングの最前線」特集号
選択された号の論文の14件中1~14を表示しています
「液中レーザープロセッシングの最前線」特集号
特 集
レーザー解説
レーザーオリジナル
  • 辻 剛志, 安友 政登, 水城 健志, 辻 正治, 川崎 英也, 米澤 徹, 真船 文隆
    2012 年 40 巻 2 号 p. 111-
    発行日: 2012年
    公開日: 2020/07/16
    ジャーナル フリー
    An effi cient method to prepare surface-assisted laser desorption ionization (SALDI) substrates which are used for mass spectrometry of biomolecules has been developed. Gold nanoparticles used as the matrix of SALDI substrate are prepared by laser ablation in liquids. To deposit the colloidal nanoparticles, electrophoresis, instead of dropping the colloidal solution onto a substrate reported in the previous study, is used, because the colloidal nanoparticles prepared by laser ablation in liquids are electronically charged. It is demonstrated that the thickness and the surface morphology of SALDI substrates are conveniently controlled by adjusting the concentration of colloids. The SALDI effi ciency for substrates prepared from colloids with higher concentrations was higher. The infl uence of the thickness and the surface morphology on the SALDI effi ciency was discussed.
  • 加賀谷 俊介, 江原 祥隆, 北本 仁孝, 舟窪 浩, 原 正彦, 山崎 陽太郎, 小田原 修, 和田 裕之
    2012 年 40 巻 2 号 p. 117-
    発行日: 2012年
    公開日: 2020/07/16
    ジャーナル フリー
    A colloidal solution of InP nanoparticles was prepared by laser ablation in liquid. An InP target was irradiated in DI water, ethanol, and hexane with a Nd:YAG laser (1064 nm, 8 ns, 10 Hz). Indium metal nanoparticles were formed as a by-product during the preparation of InP nanoparticles by laser ablation in liquid. The primary particle size did not depend on the solvent or the energy density of laser. Nanoparticles were well-dispersed in ethanol by electrostatic repulsion, and they aggregated in DI water and hexane. The zeta potential of the nanoparticles in ethanol was ‒ 76 mV. Phosphoric acid was detected in the solvent when the DI water was used as a solvent for laser ablation in liquid. The InP target was decomposed into indium and phosphorus, and phosphorus reacted with the solvent.
  • 橋本 修一
    2012 年 40 巻 2 号 p. 122-
    発行日: 2012年
    公開日: 2020/07/16
    ジャーナル フリー
    Pulsed laser-induced morphological transformation and size-reduction of colloidal gold nanoparticles in the aqueous phase were investigated using transient absorption spectroscopy and transmission electron microscopy (TEM). Femtosecond laser-induced fragmentation of gold nanoparticles within 100 ps after the laser pulse is interpreted in terms of the Coulomb explosion mechanism. On the other hand, nanosecond laser-induced size-reduction of gold nanoparticles is in good agreement with the photothermal evaporation mechanism that is based on heating of particles to temperatures above the boiling point of gold (3100 K). Here, the experimentally observed fragmentation thresholds were wellreproduced by simulations based on electron and lattice temperature models and by considering the dissipation of heat into the surrounding medium. The numerical method described herein has the advantage of identifying the fragmentation mechanism by considering pulse duration- and energydependent thresholds. To-date there is no other convenient measures to distinguish between the photothermal evaporation and the Coulomb explosion mechanisms.
  • Vladimir SVRCEK, Davide MARIOTTI, Koiji MATSUBARA, Michio KONDO
    2012 年 40 巻 2 号 p. 128-
    発行日: 2012年
    公開日: 2020/07/16
    ジャーナル フリー
    We report on investigations of silicon nanocrystals (Si-ncs) surface engineering and subsequent integrations into sub-micrometer structures induced by nanosecond laser processing in water. We present that easy and low-cost methods through nanosecond laser processing in water allow of Si-ncs integration self-assemblies ranging several micrometers and sub-micron spherical particles. Room temperature photoluminescent properties were preserved in these particles.
  • 石川 善恵, 越崎 直人, Alexander PYATENKO
    2012 年 40 巻 2 号 p. 133-
    発行日: 2012年
    公開日: 2020/07/16
    ジャーナル フリー
    We investigated a new fabrication technique for spherical particles by pulsed laser melting in liquid. In this technique, nanoparticles dispersed in liquid were melted by nanosecond pulsed laser irradiation with adequate fl uences, and the formed droplets became spherical particles after cooling. We investigated the infl uences of laser wavelength, fl uence, and dispersion medium on the obtained particles by irradiating the laser on titanium dioxide nanoparticles dispersed in ethanol and deionized water. We confirmed nanometer-sized sphere formation with submicrometer spheres by laser irradiation at relatively high laser fl uence.
一般論文
レーザーオリジナル
  • 豊田 雅宏
    2012 年 40 巻 2 号 p. 137-
    発行日: 2012年
    公開日: 2020/07/16
    ジャーナル フリー
    This paper reports the beam wave fl uctuations caused by strong atmospheric turbulence. These beam wave fl uctuations are estimated by numerical calculations carried out using moment equation analysis with thin phase screen approximation. The scintillation index for a plane wave is calculated as a function of a parameter concerning the intensity of atmospheric turbulence, and the result is in good agreement with previous studies. Transmission of the beam radius dependence of a scintillation index is calculated using the first and second moments of wave intensity. The largest scintillation index is obtained when the beam radius size equals (λ z/2π )1/2. The scintillation index of a beam wave is also evaluated using the Rytov approximation method, which is based on perturbation analysis.
レーザーレター
feedback
Top