研究者詳細 - 三澤　弘明

Photoelectrochemical submicrometer patterning of titanium dioxide by platinum

S Juodkazis, H Ishii, S Matsuo, H Misawa

JOURNAL OF ELECTROANALYTICAL CHEMISTRY 473 ( 1-2 ) 235 - 239 1999年9月

記述言語：英語出版者・発行元：ELSEVIER SCIENCE SA

Submicrometer patterning of the TiO2-rutile single crystal surface by Pt was accomplished by means of photo-catalytic reduction of PtCl42- from aqueous solutions of H2PtCl6. The patterns of Pt were fabricated along focal point traces of a 380 nm wavelength excitation laser beam. Single particles of Pt as small as 100 nm can be grown by such techniques. (C) 1999 Elsevier Science S.A. All rights reserved.

DOI： 10.1016/S0022-0728(99)00026-1

Laser-induced damage threshold and surface processing of GaN at 400 nm wavelength

PG Eliseev, HB Sun, S Juodkazis, T Sugahara, S Sakai, H Misawa

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS 38 ( 7B ) L839 - L841 1999年7月

記述言語：英語出版者・発行元：JAPAN J APPLIED PHYSICS

The laser-induced damage of epitaxially grown GaN semiconductor material is investigated for the first time by illumination of the c-plane by sub-picosecond laser pulses at the wavelength of 400 nm. The surface damage was investigated by optical and atomic force microscopies. The threshold fluence for ablation damage is determined to be similar to 5.4 J/cm(2) for pulse width of 150 fs. An application is demonstrated for laser-beam processing by the formation of clean dips on the GaN surface to depths of 240 nm in a single shot.

DOI： 10.1143/JJAP.38.L839

Fast optical switching by a laser-manipulated microdroplet of liquid crystal

S Juodkazis, M Shikata, T Takahashi, S Matsuo, H Misawa

APPLIED PHYSICS LETTERS 74 ( 24 ) 3627 - 3629 1999年6月

記述言語：英語出版者・発行元：AMER INST PHYSICS

We demonstrate the feasibility of an all-optical liquid-crystal (LC) switch with submillisecond switching time. This switch is realized by optical manipulation of a three-dimensionally trapped microscopic nematic LC droplet using an "optical tweezers." Transmission of a polarizer/LC droplet/analyzer system can be modulated at frequencies as high as 10(3) Hz, a faster response than that of a nematic LC demonstrated so far. The response corresponds to a submillisecond switching time when the LC droplet is rotated by an angle of pi/4. The alignment of the LC droplet to the plane of the incident plane-polarized beam is also demonstrated. (c) 1999 American Institute of Physics. [S0003-6951(99)00124-2].

DOI： 10.1063/1.123203

Photophysics and photochemistry of a laser manipulated microparticle

H Misawa, S Juodkazis

PROGRESS IN POLYMER SCIENCE 24 ( 5 ) 665 - 697 1999年6月

記述言語：英語掲載種別：書評論文，書評，文献紹介等出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

In this article we survey experimental results obtained by the employment of the technique called "scanning laser micromanipultion". Novel physical and chemical properties of material of micro- and sub-micrometer dimensions are elucidated by conducting experiments on an individual laser-tweezed particle. It is shown that scanning laser micromanipulation can be adopted to the particles which have a refractive index that is higher than that of the surrounding material, as well as to those which possess lower refractive index or are reflective. An implementation of this method of laser manipulation can be applied for micro-machining, optical switching and electrochemistry, as demonstrated by a series of examples. (C) 1999 Elsevier Science Ltd. All rights reserved.

DOI： 10.1016/S0079-6700(99)00009-X

Size dependence of rotation frequency of individual laser trapped liquid crystal droplets

S Juodkazis, M Shikata, T Takahashi, S Matsuo, H Misawa

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS 38 ( 5A ) L518 - L520 1999年5月

記述言語：英語出版者・発行元：JAPAN J APPLIED PHYSICS

We report the development of an all-optical liquid-crystal (LC) switch realized by laser manipulation of a three-dimensionally trapped micrometer-size nematic liquid-crystal droplet. Transmission of a polarizer/LC droplet/analyzer system can be modulated at a frequency as high as 10(3) Hz for micrometer sized LC droplets. An optical switching corresponds to the rotation of the LC droplet by an angle of pi/4. The dependence of rotation frequency on LC droplet size is explained in terms of the circularly polarized light scattering by the molecules of the LC droplet. This scattering is responsible for the transfer of angular momentum from the light to the LC droplet.

DOI： 10.1143/JJAP.38.L518

Three-dimensional microstructures created by laser microfabrication technology

M Horiyama, HB Sun, M Miwa, S Matsuo, H Misawa

JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS 38 ( 2B ) L212 - L215 1999年2月

記述言語：英語掲載種別：速報，短報，研究ノート等（学術雑誌）出版者・発行元：JAPAN J APPLIED PHYSICS

Three-dimensional microstructures with aspect ratios larger than 20 and a solidified wall with a thickness down to 2.0 mu m have been fabricated by the one-photon absorption photopolymerization technique. Lateral and longitudinal spatial resolutions in a single-line scanning process of as high as 1.0 mu m and 0.3 mu m, respectively, are reproducible. An experimental system consisting of a common picosecond pulsed laser and an optical microscope makes laser microfabrication easy to realize, implying a broad application potential.

DOI： 10.1143/JJAP.38.L212

Three-dimensional photonic crystal structures achieved with two-photon-absorption photopolymerization of resin

HB Sun, S Matsuo, H Misawa

APPLIED PHYSICS LETTERS 74 ( 6 ) 786 - 788 1999年2月

記述言語：英語出版者・発行元：AMER INST PHYSICS

Three-dimensional photonic crystal structures were fabricated with laser microfabrication techniques through two-photon-absorption photopolymerization of resin. Significant band-gap effects in the infrared wavelength region were observed from "layer-by-layer'' structures. (C) 1999 American Institute of Physics. [S0003-6951(99)03506-8].

DOI： 10.1063/1.123367

Behavior of biradicals generated from a norrish type-I reaction of 2,2-diphenylcycloalkanones. Chain-length dependence and magnetic field effects

Suzuki, I, R Tanaka, A Yamaguchi, S Maki, H Misawa, K Tokumaru, R Nakagaki, H Sakuragi

BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 72 ( 1 ) 103 - 113 1999年1月

記述言語：英語出版者・発行元：CHEMICAL SOC JAPAN

The reaction course of acyl-diphenylmethyl biradicals (alpha-oxo-omega, omega-diphenyl-alpha, omega-alkanediyl biradicals), O=C-up arrow-(CH2)(n-2)-(CPh2)-Ph-up arrow ((BR)-B-3-n), generated from the Norrish type-I reaction of 2,2-diphenylcycloalkanones (CK-n) with various ring sizes in methanol, is switched from intramolecular disproportionation (n = 6, 7), giving a diphenylalkenal, to acylphenyl recombination (n greater than or equal to 9), affording a cyclophane derivative. The behavior of (BR)-B-3-9 derived from CK-9 was studied in detail; the photolysis of CK-9 afforded an open-chain and a cyclic decarbonylation product together with an unsaturated aldehyde and a 4-methylene-2,5-cyclohexadienyl ketone (a pre-cyclophane). The photolysis of this ketone gave the same products that arose from the photolysis of CK-9, presenting the possibility that the decarbonylation products and a part of the aldehyde are formed as secondary products during irradiation.
The magnetic field dependence of the lifetimes of (BR)-B-3-n (n = 12 and 13) generated from CK-12 and 13, respectively, was measured in methanol by means of a pulsed-laser excitation technique. The rate constants for intersystem crossing showed a maximum at a relatively low field strength, which decreased with increasing the field strength to level off to an asymptotic value at > 1.5 kG. The results show that the role of hyperfine coupling in intersystem crossing is less important in these systems, presumably because of the presence of a carbonyl oxygen and the absence of a hydrogen atom at the radical center.

DOI： 10.1246/bcsj.72.103

Excitation energy transfer between dye molecules in lasing microparticles

T Takahashi, K Fujiwara, S Matsuo, H Misawa

JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY 120 ( 2 ) 135 - 140 1999年1月

記述言語：英語出版者・発行元：ELSEVIER SCIENCE SA

Energy transfer from excited state donor to ground state acceptor dyes in polymer microparticles with a diameter of 30-60 mu m was observed under lasing condition. The energy transfer efficiency was found to be higher with the increasing size of the particle. This result indicates that the excitation energy transfer efficiency can be controlled by the particle size without varying temperature and dye concentration. The dynamics of energy transfer was observed through picosecond time-resolved emission spectral measurements. (C) 1999 Elsevier Science S.A. All rights reserved.

DOI： 10.1016/S1010-6030(98)00422-5