Shunsuke Murai 교수

Abstract

We study the hybridized plasmonic-photonic modes supported by two-dimensional arrays of metallic nanoparticles coupled to light-emitting optical waveguides. Localized surface plasmon polaritons in the metallic nanoparticles can couple to guided modes in the underlying waveguide, forming quasi-guided hybrid modes, or to diffracted orders in the plane of the array, forming surface lattice resonances. We consider three kinds of samples: one sustains quasi-guided modes only, another sustains surface

High-power white-light-emitting diodes (WLEDs) comprising binderless bulk phosphors and ultraviolet (UV) LED chips as next-generation illumination sources were intensively studied. The main challenge is the effective management of different color components in each suitable crystal phase while maximizing their optical properties with near-UV excitation. In this regard, we developed glass-ceramics that contain Na5Gd9F32 and NaAlSiO4, in which the phase-selective distribution of Eu3+ and Eu2+ resu

Abstract

Bound states in the continuum (BICs) are electromagnetic modes with a dispersion inside the light cone and infinite lifetimes. This exceptional property has led to intensive research and the demonstration of BICs in the gigahertz, teraherz, and near-infrared, up to the visible region. In this study, we design and experimentally demonstrate optical BICs using a subdiffraction lattice of Si nanodisks. The out-of-plane magnetic dipole resonance in the dielectric nanodisks couples with the subdiffra

ADVERTISEMENT RETURN TO ISSUEPREVArticleSynthesis via silyl alkenyl ethers. IV. Synthesis of 1-hydroxybicyclo[n.1.0]alkanes from silyl alkenyl ethers. Novel class of cyclopropanolsS. Murai, Tomoyuki Aya, and Noboru SonodaCite this: J. Org. Chem. 1973, 38, 25, 4354–4356Publication Date (Print):December 1, 1973Publication History Published online1 May 2002Published inissue 1 December 1973https://pubs.acs.org/doi/10.1021/jo00964a037https://doi.org/10.1021/jo00964a037research-articleACS Publications

We have fabricated two-dimensional periodic arrays of titanium nitride (TiN) nanoparticles from epitaxial thin films. The thin films of TiN, deposited on sapphire and single crystalline magnesium oxide substrates by a pulsed laser deposition, are metallic and show reasonably small optical loss in the visible and near infrared regions. The thin films prepared were structured to the arrays of nanoparticles with the pitch of 400 nm by the combination of nanoimprint lithography and reactive ion etch

Abstract Various optical phenomena can be induced in periodic arrays of nanoparticles by the radiative coupling of the local dipoles in each particle. Probably the most impressive example is bound states in the continuum (BICs), which are electromagnetic modes with a dispersion inside the light cone but infinite lifetime, that is, modes that cannot leak to the continuum. Symmetry‐protected BICs appear at highly symmetric points in the dispersion of periodic systems. Although the addition of none

Abstract Aluminum (Al) is known as a plasmonic material effective in a wide frequency range up to the ultraviolet, while its plasmonic properties in the near infrared region have been less explored. In this study, up‐conversion (UC) photoluminescence is amplified by using an Al nanostructure to demonstrate that Al is a useful plasmonic material in the near infrared region as well. A periodic lattice of Al nanocylinders is selected as a plasmonic nanostructure, where the size of nanocylinder and

A plasmonic array, consisting of metallic nanocylinders periodically arranged with a pitch comparable to the optical wavelength, is a system in which both the localized surface plasmon polaritons (SPPs) and diffraction in the plane of the array are simultaneously excitable. When combined with a phosphor film, the array acts as a photoluminescence (PL) director and enhancer. Since the array can modify both excitation and emission processes, the overall modification mechanism is generally complex

We have developed a method for fabricating thin layers of Ce3+ doped yttrium aluminium garnet, Y3Al5O12 (YAG:Ce) based on a sol-gel approach with propylene oxide as a gelation initiator. A single spin-coating process followed by a sequence of heat treatments allows the fabrication of polycrystalline YAG:Ce thin layers with a thickness of a few hundreds of nanometers. Surface morphology, crystallite size, and quantum efficiency are examined as a function of heat treatment temperature. The optical

We have synthesized hierarchically porous Y3Al5O12 (YAG) ceramics doped with trivalent cerium (Ce3+) ions (YAG:Ce) by the sol–gel process and examined their optical properties including scattering strength. Starting from the ionic precursors, i.e., AlCl3·6H2O, YCl3·6H2O, CeCl3·7H2O, and poly(ethylene oxide) (PEO) dissolved in a mixture of water and ethanol, monolithic wet gels are synthesized using propylene oxide as a geletion initiator. PEO induces phase separation parallel to the gelation in

Rare-earth-doped up-converters with Yb3+ as a sensitizer show a high internal conversion efficiency under the excitation at wavelength λ = 980 nm. For the solar cell applications of up-converters, however, there is a problem that the solar light at λ = 980 nm is absorbed by the water molecule in the atmosphere. While Nd3+ co-doping allows the up-conversion at the transparent window of water around λ = 800 nm, the absorption coefficient of Nd3+ is still small due to the forbidden nature of 4f–4f

The incorporation of upconversion luminescence (UCL) materials into various plasmonic structures promotes light-matter interactions in nanophotonic systems. It has been experimentally demonstrated that UCL enhancement entailing two photons exhibits a quadratic dependence on the excitation intensity. However, in the field of plasmonics, there have not been sufficient studies on high-order multi-photon upconversion processes. We report up-to-five-photon UCL, wherein λ = 1550 nm near-infrared light

Phase-separation behavior in the sol−gel system of alumina−silica (Al2O3−SiO2) in the presence of poly (ethylene oxide) has been investigated. Amorphous gels with interconnected macropores can be obtained from the starting composition containing up to 10 mol % Al3+ by inducing phase separation parallel to the sol−gel transition. SmCl3·6H2O is added to the present system to yield Sm3+-doped macroporous gels. The sintered Al2O3−SiO2 macroporous glasses doped with Sm3+ exhibit the photoluminescence