Daisuke Ueda

Preparation and application of lanthanide complex incorporated ormosil composite phosphor films

Abstract Transparent-phosphor films were prepared from organically modified-silicates (ormosil) sol solutions doped with europium phenanthroline complex, [Eu(phen) 2 ]Cl 3 , by dip-coating. Their optical properties were characterized by refractive index, absorption, reflection, and luminescence spectra. Luminescent-solar-concentrator panels were made by coating the ormosilxa0:xa0[Eu(phen) 2 ] 3+ film with n =ca.xa01.40 on quartz plates, so that they showed 10–15% increases in the photovoltaic current of crystalline silicon solar cells by the fluorescence of the coated phosphor film, which converts the UV component of sunlight to the visible lights.

Volumetric Optical Recording Using a 400 nm All-Semiconductor Picosecond Laser

We have demonstrated volumetric optical recording using an all-semiconductor picosecond laser, which generated optical pulses with a duration of 3 ps and a maximum peak power of 100 W at a wavelength of 404 nm and a repetition frequency of 1 GHz. This pulsed laser system efficiently induced multiphoton absorption in the recording media due to its high peak power and high repetition rate. The recording marks were formed as submicrometer voids inside a single thick recording layer by multiphoton absorption. A clear readout signal was obtained from the recorded marks.

Structural Modification‐Induced Valence Change of the Europium Ion Doped in Barium Octaborate

Valence states of the europium ion doped in barium octaborate, , were alternately changed between the trivalent and divalent ones by performing the crystallization or vitrification treatment for the host material in air at , and such valence change characteristics were discussed on the basis of the mutual transformation between and units and their connection manners via bridged oxygens in the networks of crystalline and vitreous forms, so that the redox mechanism proposed was applied to other metal borate host materials to predict and control the valence state of ions. ©1999 The Electrochemical Society

Persistent spectral hole burning of Eu (III) complex dispersed silica composite materials prepared by sol–gel method

Abstract Europium (III) complex [Eu(15-crown-5)]Cl3, was doped into SiO2 matrices derived from tetraethyl orthosilicate (TEOS) by the sol–gel method. The properties of persistent spectral hole burning (PSHB) were characterized by the burning temperature and the temperature cycling experiment. For SiO2xa0:xa0[Eu(15-crown-5)]3+, the spectral holes were burned at the temperatures between 10 and 300xa0K. In comparison with SiO2xa0:xa0Eu3+, the formation efficiency of the holes was enhanced by the complexation of Eu3+ ions with crown ether ligands. The hole formation mechanism was discussed on the basis of quantitative analysis of the PSHB characters.

Dynamic Recording of 200 Gbytes in Three-Dimensional Optical Disk by a 405 nm Wavelength Picosecond Laser

We present experimental results of our volumetric optical data storage system. To achieve volumetric recording over a wide depth range of 250 µm in a recording medium, we developed a relay lens system for compensating for the spherical aberration of a high-numerical-aperture (0.85) objective lens. The disk employs a single monolithic recording layer and a reference layer for servo control. A 405-nm-wavelength titanium:sapphire laser that exhibits 2 ps pulse duration and a more than 2 kW peak power is used for recording. We adopted void formation and mark position as recording principles. We have experimentally demonstrated 34-layer dynamic recording, corresponding to a capacity of 200 Gbytes.

Preparation of Transparent Inorganic‐Organic Composite Phosphors Incorporated with Europium (III) Complexes

Transparent organically modified silicates (ORMOSIL) glass phosphors with high emission intensity (~60% vs. Y(P,V)O 4:Eu) were prepared by incorporating with [Eu(phen) 2]Cl3 under optimized conditions for the ORMOSIL composition and complex concentration, and their emission intensity variety was characterized by the D0-F2 to D0-F1 emission intensity ratio. Waveguide-type sunlight collector panels made of quartz plates coated with the ORMOSIL glass phosphor film showed an apparent enhancement for the photovoltaic output of silicon solar cells by its fluorescence wavelength shifting effect.

Three-Dimensional Imaging Using Spherical Ultrasound Wave Generated by Laser-Induced Breakdown.

In this paper, we propose a new framework of ultrasonic (US) three-dimensional (3D) imaging, introducing laser-induced breakdown (LIB) as an acoustic source. LIB is a phenomenon in which a substance is transformed to a plasma by a pulsed laser beam. LIB explosively emits a variety of energies such as heat, light and sound which also includes pulsed ultrasound. Emitted US waves have suitable characteristics for US 3D imaging in terms of low directivity, enabling a wide view and sharply pulsed waves. Utilizing these characteristics, we attempt to apply the synthetic aperture method for frontal 3D imaging in a real-time process. Experimental results show that even sparsely arrayed sensors allow a wider frontal view than that allowed in the case using existing transducers.