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Volume 25, Issue 11
Displaying 1-17 of 17 articles from this issue
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Mitsunobu MIYAGI1997 Volume 25 Issue 11 Pages 731
Published: November 15, 1997
Released on J-STAGE: February 26, 2010
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Future PerspectiveHiroshi MASUHARA1997 Volume 25 Issue 11 Pages 732
Published: November 15, 1997
Released on J-STAGE: February 26, 2010
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Recent Theoretical DevelopmentsKikuo CHO, Jun USHIDA1997 Volume 25 Issue 11 Pages 733-737
Published: November 15, 1997
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSThe importance of considering the quantum mechanical coherence of the eigenstates of nano-scale materials is stressed in theoretical schemes for their optical responses. This leads to the nonlocal form of susceptibilities in contrast with the traditional theory of macroscopic optical responses, and a rough sketch is given about the microscopic nonlocal response theory. Two examples are mentioned: (a) Size quantization of excitons in the presence of electron-hole exchange interaction, with an introduction to the two fundamental approaches in the definition of “matter” and “external field”, and (b) the coupling of an atomic excitation with a whispering gallery mode of a dielectric sphere, leading to vacuum Rabi split, coupled modes.View full abstractDownload PDF (1034K) -
[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...1997 Volume 25 Issue 11 Pages 737-737,744
Published: November 15, 1997
Released on J-STAGE: February 26, 2010
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Tadashi ITOH1997 Volume 25 Issue 11 Pages 738-744
Published: November 15, 1997
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSOptical properties of semiconductor nano particles are reviewed, especially on I-VII and II-VI compounds from the view points of fundamental photophysics brought about by quantum size effects on three-dimensionally confined excitonic systems and also of new prospective functional photonic materials. Various kinds of size-dependent excitonic properties in nano particles of individual sizes or individual nano particles are found by means of size-selective excitation and microspectroscopic photo-luminescence measurements. Near-field optical responses in assembled nano particles are also discussed. Their potentialities for application to nano opto-electronic devices are briefly mentioned.View full abstractDownload PDF (1337K) -
Masahiro KOTANI1997 Volume 25 Issue 11 Pages 745-747
Published: November 15, 1997
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSProblems involving microheterogeneity are expected to be more important in exciton dynamics, energy transfer and reaction kinetics as the size of the heterogeneity such as crystallite sizes and domain sizes decreases. An ion trap is proposed as an experimental means to conduct measurements with a well defined microcrystal.View full abstractDownload PDF (667K) -
Hideki FUKUMOTO, Hiroshi FUKUMURA, Hiroshi MASUHARA1997 Volume 25 Issue 11 Pages 748-753
Published: November 15, 1997
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPolymeric microspheres ranging from 2 to 60μm were doped with anthracene or coated with a Cuphthalocyanine derivative, being adhered on quartz plates, were irradiated with a nanosecond pulsed laser in air. Ejection behavior of the spheres was studied by nanosecond photography. Even when one single sphere was irradiated, its ejection was confirmed to take place. Irradiation of cohesive films of microspheres also induced explosive ejection of spheres. It was found that the ejection starts with a certain retention period after laser pulse irradiation. The retention period falls in the range from sub to tens of is, depending on the excitation wavelength, laser fluence, the size of spheres and the concentration of photo-absorbing molecules at the sphere surface. This suggests that photothermal expansion of spheres induce a movement of the center of mass in a short time range, which yields a force overcoming their adhesion to the surface of quartz plates. It was also demonstrated that one single sphere can be selectively ejected from a cohesive film of microspheres by laser irradiation under a microscope.View full abstractDownload PDF (1794K) -
Noboru KITAMURA, Haeng-Boo KIM1997 Volume 25 Issue 11 Pages 754-759
Published: November 15, 1997
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSLaser trapping-microspectroscopy and confocal laser fluorescence microspectroscopy have been applied to analyze inhomogeneous structures in single microparticles. In the case of melamine-resin microcapsules containing a toluene solution of a tetraphenylporphyrine derivative, the capsules showed an extraordinary diameter dependence of dye absorbance, and the results were explained in terms of the size-dependent distribution of the dye between the inner tolune and melamine resin phases. Single particle measurements were shown to be absolutely necessary to elucidate characteristic features of the chemistry of microparticles.View full abstractDownload PDF (1096K) -
Jun-ichi HOTTA, Keiji SASAKI, Hiroshi MASUHARA1997 Volume 25 Issue 11 Pages 760-764
Published: November 15, 1997
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSLaser manipulation of a single microparticle in solution by photon pressure and its application for molecular assembling was reviewed. By focusing a cw-Nd:YAG laser under a microscope, invisible microparticles, swelled micelles, polymer chains were trapped leading to formation of a micrometer-sized particle. The characteristic of the formed particle was analyzed by fluorescence microspectroscopy. In the formed polymer particle, condensation of π-electronic chromophore was confirmed by dimer formation. Fusion of swelled micelles was proved by observing Förster type intermolecular energy transfer. Photothermal effect upon particle formation process in water was also investigated for temperature-sensitive intelligent polymers. Photon pressure provides novel micromanipulation and microfabrication tools and will open the new stage of chemistry.View full abstractDownload PDF (917K) -
Hidetoshi OIKAWA, Hachiro NAKANISHI1997 Volume 25 Issue 11 Pages 765-769
Published: November 15, 1997
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSReprecipitation method is a convenient technique to fabricate organic microcrystals. The crystal size is usually several tens of nanometer to less than a micrometer. The process of microcrystal formation by this method has been investigated and the mechanism for the microcrystal formation has been established. As a result, a guide line for crystal size control has been proposed, and poly (DCHD) microcrystal as small as 15 nm was prepared successfully. The excitonic absorption peak of microcrystals was blue-shifted with decreasing crystal size. The emission spectrum also changed with crystal size. It was suggested that the abovementioned blue-shift is due to strong coupling between exciton and phonon. Finally, some results with regard to nonlinear optical properties for microcrystals were summarized.View full abstractDownload PDF (1106K) -
Daisuke TAKASU, Takuzo AIDA1997 Volume 25 Issue 11 Pages 770-775
Published: November 15, 1997
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSDendrimers are three-dimensional, hyper-branched macromolecules with well-defined junction points and molecular weights, which have attracted considerable attentions as new nanoscale materials. In the present review article are described recent developments of functional dendrimers, where “electron transfer”-active dendritic molecules are highlighted.View full abstractDownload PDF (959K) -
Osamu ITO1997 Volume 25 Issue 11 Pages 776-780
Published: November 15, 1997
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPhotochemical properties of carbon clusters such as C60 and C70 have been widely studied on the viewpoints of scientific and technological interests. Photo-illumination of fullerenes leads to their excited states which have different character from that of the ground state. For example, an increase in the photoinduced electric conductivity of polymers was found by doping with C60 and C70. Fullerenes such as C60 and C70 show photoinduced charge separation from their excited states in the presence of appropriate electron donors or acceptors. These photochemical studies are the basis of potential uses of fullerenes as each particle material. The laser flash photolysis studies in solution, solid films, and fine particles are reviewed.View full abstractDownload PDF (939K) -
Yoshio NOSAKA1997 Volume 25 Issue 11 Pages 781-785
Published: November 15, 1997
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSLaser spectroscopy has been applied to investigating photoinduced or photocatalytic reactions on semiconductor particles. Furthermore, the laser photophysics of semiconductor nanoparticles is most important in the field of new materials. Recent investigations of single particles appear that a slight sizedistribution prevents accurate analysis in the photophysics. Since the photoinduced reactions have been studied so far on an ensemble of particles, the reaction on a single particle may provide a new insight into the heterogeneous reactions. Based on this aspect, in the present review, we comment on the photoinduced processes at the semiconductor, the recent development in the field of semiconductor nanoparticles, and the specific points of the photoinduced dynamics in the reaction system of nanoparticles. We referred recent reports on the photophysics and electronic properties of a single semiconductor nanoparticle, and suggest the possibility of developing new research field of single particle photochemistry.View full abstractDownload PDF (1023K) -
Shinjiro MACHIDA, Kazuyuki HORIE1997 Volume 25 Issue 11 Pages 786-789
Published: November 15, 1997
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSPHB studies performed for polymer nanoparticle systems bearing single dye molecules are reviewed. In polymer nanoparticle systems with a single dye molecule, such as hemeproteins and anphiphilic polymer micelles, nanoscopic environments of the dye molecule play important roles for their function. Photochemical hole burning (PHB) (or more generally persistent spectral hole burning) is a sensitive spectroscopy to study the interaction between a doped dye molecule and a surrounding matrix. Homogeneous and inhomogeneous widths, hole broadening properties, and pressure effects of substituted myoglobin suggest that proteins have more ordered nanoenvironments than conventional amorphous systems. Low-energy excitation mode of a polymer micelle with a porphyrine dye and cyclododecyl groups indicated the strong packing of the cyclododecyl groups in the micellar systems.View full abstractDownload PDF (584K) -
Ken-ichi HAYASHI1997 Volume 25 Issue 11 Pages 790-794
Published: November 15, 1997
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSGlass is an excellent amorphous material for its transparency, hardness and electric insulation. Industrial laser processing of glass has been performed mainly in the case of surface marking. Soda lime glass and non-alkali glass were processed by a laser ablation technique to obtain high aspect ratio holes. The 5th harmonic pulse of Nd:YLF laser (λ = 209nm) was used. The laser energy was 40μJ/pulse and the pulse width was 12ns FWHM. When the laser beams were highly focused on the glass, SEM photographs showed no cracks or damages on the surface around the holes. The holes with the diameter of 10μm and the depth of 1 mm were obtained and the aspect ratio of the holes was about 100.View full abstractDownload PDF (1669K) -
Shigeki FUJINAGA, Hiroshi MIURA, Toru NARIKIYO, Seiji KATAYAMA, Akira ...1997 Volume 25 Issue 11 Pages 795-801
Published: November 15, 1997
Released on J-STAGE: February 26, 2010
JOURNAL FREE ACCESSA high power YAG laser processing system, in which the beams of three YAG lascrs (two 2.0kW continuous wave oscillator and a 1.5kW pulsed oscillator) were integrated into a single optical fiber, was developed. The beams of three lasers were focused at the input end of the optical fiber and transmitted to the processing point through the optical fiber. It was confirmed that the energy density distribution of the integrated beam even at the defocused point of the processing optics was similar to that of one oscillator without splitting to the three beams, and complex pulse shape control of the laser power became possible by integrating modulated beams of three lasers. Using this processing system, it was also confirmed that the penetration depth depended on a superimposing delay time of a pulsed laser beam to continuous wave laser modulated beams in a rectangular shape. Effective delay time of the pulsed laser beam was two or three milliseconds for the production of the deepest penetration in welding of SUS304 stainless steel.View full abstractDownload PDF (1827K) -
What is Stimulated Emission?Mitsuo MAEDA1997 Volume 25 Issue 11 Pages 802-810
Published: November 15, 1997
Released on J-STAGE: February 26, 2010
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