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Ito K.,Toyota Central Research and Development Labs. Inc. | Ito K.,Tokyo University of Science | Toshiyoshi H.,Tokyo University of Science | Iizuka H.,Toyota Central Research and Development Labs. Inc.
Optics Express | Year: 2016

Metal-insulator-metal metamaterial thermal emitters strongly radiate at multiple resonant wavelengths. The fundamental mode, whose wavelength is the longest among resonances, is generally utilized for selective emission. In this paper, we show that parasitic modes at shorter wavelengths are suppressed by newly employed densely-tiled resonators, and that the suppression enables quasi-monochromatic thermal emission. The second-order harmonics, which is excited at half the fundamental wavelength in conventional emitters, shifts toward shorter wavelength. The blue-shift reduces the amplitude of the second-order emission by taking a distance from the Wien wavelength. Other parasitic modes are eliminated by the small spacing between resonators. The densely-tiled resonators are fabricated, and the measured emission spectra agree well with numerical simulations. The methodology presented here for the suppression of parasitic modes adds flexibility to metamaterial thermal emitters. © 2016 Optical Society of America. Source


Niclass C.,Toyota Central Research and Development Labs. Inc. | Soga M.,Toyota Central Research and Development Labs. Inc.
Technical Digest - International Electron Devices Meeting, IEDM | Year: 2010

A CMOS single-photon detector, including a highly miniaturized active recharge circuit, achieving the highest counting rate yet reported for an afterpulsing-free Geiger-mode photodiode is introduced. Thanks to its low-noise and 6-ns dead time figure, a dynamic-range of 116dB for steady-state photon counting in a single acquisition time of 20ms was achieved. ©2010 IEEE. Source


Tanaka T.,Toyota Central Research and Development Labs. Inc. | Tajima I.,Toyota Central Research and Development Labs. Inc. | Kato Y.,Toyota Central Research and Development Labs. Inc. | Nishihara Y.,Okayama University | Shinjoh H.,Toyota Central Research and Development Labs. Inc.
Applied Catalysis B: Environmental | Year: 2011

A Ba-Ti composite oxide was formed on a NOx storage and reduction catalyst via impregnation of a Ba-Ti precursor solution composed of H2O2 added to a complex prepared using the citric acid method. The structure of the Ba-Ti composite in solution was analyzed by chemical composition analysis and FT-Raman and UV-vis spectroscopy. MM2 calculations were performed to propose its chemical structure. Both Ba and Ti together were found to form a composite molecule in the solution. Furthermore, TEM-EDX and XRD analyses of the Ba-Ti composite oxide on the catalyst prepared by impregnation with the Ba-Ti composite aqueous solution revealed that Ba and Ti in the catalyst were highly dispersed at the nm scale. The formation of the Ba-Ti composite oxide on the NSR catalyst enhanced sulfur desorption efficiency and led to high-performance NOX conversion as a NOX storage and reduction activity catalyst after desulfation treatment. It was assumed that the existence of nano-scaled Ba compounds combined with Ti was efficient for the inhibition of the sintering of barium sulfate and its facile decomposition. It was found that dispersion of Ba compounds for NOX storage materials using a Ba-Ti complex solution is an efficient way to improve the durability of NSR catalysts. © 2011 Elsevier B.V. Source


Hasegawa K.,Toyota Central Research and Development Labs. Inc. | Ichikawa T.,Toyota Central Research and Development Labs. Inc. | Mizuno S.,Toyota Central Research and Development Labs. Inc. | Takeda Y.,Toyota Central Research and Development Labs. Inc. | And 4 more authors.
Optics Express | Year: 2015

We report energy transfer efficiency from Cr3+ to Nd3+ in Nd (1.0 at.%)/Cr (0.4 at.%) co-doped Y3Al5O12 (YAG) transparent ceramics in the laser oscillation states. The laser oscillation has performed using two pumping lasers operating at 808 nm and 561 nm; the former pumps Nd3+ directly to create the 1064 nm laser oscillation, whereas the latter assists the performance via Cr3+ absorption and sequential energy transfer to Nd3+. From the laser output power properties and laser mode analysis, the energy transfer efficiency was determined to be around 65%, which is close to that obtained from the spontaneous Nd3+ emission. © 2015 Optical Society of America. Source


Yamada Y.,Toyota Central Research and Development Labs. Inc. | Nakamura T.,Toyota Central Research and Development Labs. Inc. | Yano K.,Toyota Central Research and Development Labs. Inc.
Journal of Colloid and Interface Science | Year: 2016

A facile one-pot synthesis for the composite materials fabricated from conjugated polymer, poly(p-phenylenevinylene) (PPV), and monodispersed mesoporous silica spheres (MMSS) is demonstrated. Composite materials having superior photoluminescence properties are easily obtained using ethylene glycol as a reaction solvent in which PPV monomers are effectively exchanged with cationic surfactants in MMSS and subsequently polymerized in the solution. The method can prevent serious reduction of photoluminescence properties which occurs inevitably during thermal treatment (200 °C) to polymerize PPV. In our method, the temperature of 100 °C is enough to obtain the fully polymerized PPV, which is confirmed in Fourier transform infrared (FT-IR) spectrum. Reaction mechanism is verified through direct observation of its distinguishable color changes in the reaction solution and the measurement of surface electrical potential (ζ-potential). The obtained results strongly support that PPV chains are impregnated within mesopores in isolated condition, leading to high fluorescence quantum yield (nearly 80%). Compared to the conventional route, this method reduces multistep synthesis to one-step and eliminates high temperature and high vacuum process, leading to the facile eco-friendly procedure. © 2016 Elsevier Inc. Source

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