Katsuhisa Tanaka

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We experimentally demonstrate the capability of tailoring lasing resonance properties by manipulating the coupling between surface plasmons and photons in random lasing media composed of metallic-dielectric core-shell nanoparticles and organic dyes. It is revealed that core-shell nanoparticle-based systems exhibit optical feedback features distinctive from(More)
Magnetic properties have been investigated for a zinc ferrite thin film deposited on glass at a substrate temperature close to room temperature using a sputtering method. X-ray diffraction analysis reveals that the thin film consists of nanocrystalline ZnFe(2)O(4) with the size of approximately 10 nm. The magnetization at 300 K as a function of the external(More)
Stable carbon (δ13C) and nitrogen (δ15N) isotope ratios were measured to investigate the migration of John’s snapper Lutjanus johnii and its dependence on the food resources provided within the large Matang Mangrove Forest Reserve (40,151 ha), Malaysia. John’s snapper, and its main prey food such as penaeids, Acetes shrimps and mysids, showed generally(More)
The study of carrier multiplication has become an essential part of many-body physics and materials science as this multiplication directly affects nonlinear transport phenomena, and has a key role in designing efficient solar cells and electroluminescent emitters and highly sensitive photon detectors. Here we show that a 1-MVcm(-1) electric field of a(More)
A SPASER, short for surface plasmon amplification by stimulated emission of radiation, is key to accessing coherent optical fields at the nanoscale. Nevertheless, the realization of a SPASER in the visible range still remains a great challenge because of strong dissipative losses. Here, we demonstrate that room-temperature SPASER emission can be achieved by(More)
In this work, we report the optical properties of Tm ions in tellurite glasses (TeO2-TiO2-Nb2O5) for different Tm 3+ concentrations ranging between 0.05 and 1 wt%. Judd-Ofelt intensity parameters have been determined to calculate the radiative transition probabilities and radiative lifetimes of excited states. The stimulated emission cross-sections of the(More)
Large-scale battery systems are essential for efficiently utilizing renewable energy power sources from solar and wind, which can generate electricity only intermittently. The use of lithium-ion batteries to store the generated energy is one solution. A long cycle life is critical for lithium-ion battery when used in these applications; this is different(More)
The enhanced magneto-optical properties of nanoscaled lanthanide chalogenide semiconductors which have a wide energy gap were observed at around 500 nm for the first time. The nanoscaled semiconductors, Eu(1-x)Se nanoparticles 1 (cubic shapes) and 2 (spherical shapes), were synthesized by the thermal reduction of Eu(III) ion with organic ligands containing(More)
The spaser, a quantum amplifier of surface plasmons by stimulated emission of radiation, is recognized as a coherent light source capable of confining optical fields at subwavelength scale. The control over the directionality of spasing has not been addressed so far, especially for a single-particle spasing nanocavity where optical feedback is solely(More)
In this work, we report the spectroscopic properties of the infrared H4→F4 emission of Tm ions in two different compositions of glasses based on TeO2, WO3, and PbO for three Tm2O3 concentrations (0.1, 0.5, and 1 wt%). Judd-Ofelt intensity parameters have been determined and used to calculate the radiative transition probabilities and radiative lifetimes.(More)