Rare-earth-doped oxynitride or nitride compounds have been reported to be photoluminescent and may then serve as new phosphors with good thermal and chemical stabilities. In this work, Ca-␣-SiAlON:Eu 2+ based yellow and orange oxynitride phosphors with compositions of Ca 0.485 Eu 0.015 Si 9.2 Al 2.8 O 1.8 N 14.2 and Ca 0.94 Eu 0.06 Si 9 Al 3 ON 15 were prepared using the gas-pressured sintering method. The crystallinity and particle morphology of the prepared phosphors were characterized. The temperature dependence of photoluminescence properties was investigated from 25 to 150°C. The Stokes shift and zero-phonon line was calculated mathematically and estimated from the spectral data. The prepared Ca-␣-SiAlON:Eu 2+ phosphors showed superior thermal quenching properties compared to commercially used YAG:Ce 3+ phosphors. In addition, the activation energies ͑⌬E͒ for thermal quenching of the prepared Ca-␣-SiAlON:Eu 2+ phosphors were determined by Arrhenius fitting.

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We evaluated and demonstrated strong vertical-coupling characteristics of vertical directional couplers based on long-range surface plasmon polaritons (LRSPPs) at 1.55μm wavelength. Fundamental even and odd modes supported by LRSPP metal-stripe waveguides compete more strongly on vertical coupling structures than on lateral coupling structures, possibly leading to less power consumption for switching and to compactness in device length and width. LRSPP-based vertically coupled routing of signals can also be a powerful means of developing three-dimensional photonic integrated circuits and optical printed circuit boards.

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has great potentials as a down-conversion green phosphor for white light emitting diodes (LEDs) utilizing near UV or blue LEDs as the primary light source.