• Journal of KSNVE
• /
• v.7 no.3
• /
• pp.449-455
• /
• 1997

A theoretical study is presented for the prediction of the scattering of obliquely incident plane acoustic wave by transversely isotropic cylindrical shells immersed in water. In dorder to illustrate the vailidity of the theory backscattering form functions are compared with the existing results for degenerated problems: the catterings by isotropic shell and transversely isotropic solid cylinder. The unidirectional fiber reinforced boron-aluminum composites are selected as a model of transversely isotropic materials having potential applications in practice. From the resonant scattering analysis of the partial backscattering form functions, the dispersion curves for fluid-borne Stoneley wave, guided wave along the shell, and the lowest three Lamb type waves can be found. The Lamb type dispersions are compared with those of the flat plate. The variation of anisotropy significantly affects the properties of circumferential waves. From these results, it can be possible to identify parametrically the material properties of anisotropic cylindrical targets.

• 한국초전도학회:학술대회논문집
• /
• 2009.07a
• /
• pp.5-5
• /
• 2009

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.9
• /
• pp.1260-1263
• /
• 2013

Plane wave scattering from a spherical resonator is calculated by solving the combined field integral equation (CFIE) with Rao-Wilton-Glisson (RWG) basis functions and the moment method. The calculations show that magnetic and electric dipoles are found at resonant modes. These characteristics are confirmed by radiation patterns in the far field region. In addition, an analysis of a magnetodielectric sphere is discussed.

• Journal of the Korean Magnetics Society
• /
• v.20 no.4
• /
• pp.160-166
• /
• 2010

X-ray resonant magnetic scattering (XRMS) allows us to extract magnetic depth profiles in magnetic multilayers and magnetization distribution in magnetic nanostructures in element-specific manner using x-ray reflectivity and diffraction. XRMS is explained with a brief introduction and examples of magnetic structures and magnetic switching mechanism in magnetic multilayers and nanostructures.

• Current Applied Physics
• /
• v.18 no.11
• /
• pp.1225-1229
• /
• 2018

In this paper, we investigated the electronic structures and defect states of $SrLaMgTaO_6$ (SLMTO) double perovskite structures by using resonant inelastic x-ray scattering. Recently, $Eu^{3+}$ doped SLMTO red phosphors have been vigorously investigated due to their higher red emission efficiency compared to commercial white light emitting diodes (W-LED). However, a comprehensive understanding on the electronic structures and defect states of host SLMTO compounds, which are specifically related to the W-LED and photoluminescence (PL), is far from complete. Here, we found that the PL spectra of SLMTO powder compounds sintered at a higher temperature, $1400^{\circ}C$, were weaker in the blue emission regions (at around 400 nm) and became enhanced in near infrared (NIR) regions compared to those sintered at $1200^{\circ}C$. To elucidate the difference of the PL spectra, we performed resonant inelastic x-ray spectroscopy (RIXS) at Ta L-edge. Our RIXS result implies that the microscopic origin of different PL spectra is not relevant to the Ta-related defects and oxygen vacancies.

• Current Applied Physics
• /
• v.18 no.11
• /
• pp.1212-1217
• /
• 2018

The electric field-induced modifications of magnetic anisotropy in CoFeB/MgO systems are studied using X-ray resonant magnetic scattering and magneto-optical Kerr effect. Voltage dependent changes of the magnetic anisotropy of -12.7 fJ/Vm and -8.32 fJ/Vm are observed for Ta/CoFeB/MgO and Hf/CoFeB/MgO systems, respectively. This implies that the interfacial perpendicular magnetic anisotropy is reduced (enhanced) when electron density is increased (decreased). X-ray resonant magnetic scattering measurements reveal that the small in-plane magnetic component of the remanent state of CoFeB/MgO systems with weak magnetic anisotropy changes depending on the applied voltage leading to modification of the magnetic anisotropy at the CoFeB/MgO interface.

• Korean Journal of Optics and Photonics
• /
• v.6 no.4
• /
• pp.337-344
• /
• 1995

We have detected the resonant stimulated Raman scattering signal when the Q-switched Nd:YAG laser beam are incident on the $35~62{\mu}m$ sized water droplet as pump beam. The signals appeared as uniformly spaced peaks and the intervals between peaks become narrow as the droplet size increases. Also we have confirmed the morphology dependent resonances (MDR's) characteristic of the stimulated Raman scattering signal when the water droplet becomes nearly spherical shape after two water droplets are coupled to a droplet. The error in the measured intervals between MDR's of same mode order is about 5%.out 5%.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.76.1-76.1
• /
• 2015

Optical resonances of metallic or dielectric nanoantennas enable to effectively convert free-propagating electromagnetic waves to localized electromagnetic fields and vice versa. Plasmonic resonances of metal nanoantennas extremely modify the local density of optical states beyond the optical diffraction limit and thus facilitate highly-efficient light-emitting, nonlinear signal conversion, photovoltaics, and optical trapping. The leaky-mode resonances, or termed Mie resonances, allow dielectric nanoantennas to have a compact size even less than the wavelength scale. The dielectric nanoantennas exhibiting low optical losses and supporting both electric and magnetic resonances provide an alternative to their metallic counterparts. To extend the utility of metal and dielectric nanoantennas in further applications, e.g. metasurfaces and metamaterials, it is required to understand and engineer their scattering characteristics. At first, we characterize resonant plasmonic antenna radiations of a single-crystalline Ag nanowire over a wide spectral range from visible to near infrared regions. Dark-field optical microscope and direct far-field scanning measurements successfully identify the FP resonances and mode matching conditions of the antenna radiation, and reveal the mutual relation between the SPP dispersion and the far-field antenna radiation. Secondly, we perform a systematical study on resonant scattering properties of high-refractive-index dielectric nanoantennas. In this research, we examined Si nanoblock and electron-beam induced deposition (EBID) carbonaceous nanorod structures. Scattering spectra of the transverse-electric (TE) and transverse-magnetic (TM) leaky-mode resonances are measured by dark-field microscope spectroscopy. The leaky-mode resonances result a large scattering cross section approaching the theoretical single-channel scattering limit, and their wide tuning ranges enable vivid structural color generation over the full visible spectrum range from blue to green, yellow, and red. In particular, the lowest-order TM01 mode overcomes the diffraction limit. The finite-difference time-domain method and modal dispersion model successfully reproduce the experimental results.

• Journal of the Korean Vacuum Society
• /
• v.15 no.2
• /
• pp.162-167
• /
• 2006

The symmetry of the conduction-band minimum of $GaAs_{1-x}N_{x}$ is probed by performing resonant Raman scattering (RRS) on thin layers of $GaAs_{1-x}N_{x}(x{\leq}0.7)$ epitaxially grown on Ge substrates. Strong resonance enhancement of the LO(longitudinal optical)-phonon Raman intensity is observed with excitation energies near the $E_0$ as well as $E_+$ transitions, However, in contrast to the distinct LO-phonon line-width resonance enhancement and activation of various X and L zone-boundary phonons brought about slightly below and near the $E_+$ transition, respectively, we have not observed any resonant LO-phonon line-width broadening or activation of sharp zone-boundary phonons near the $E_0$ transition. The observed RRS results reveal that the conduction-band minimum of GaAsN predominantly consists of the delocalized GaAs bulk-like states of ${\Gamma}$ symmetry.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.11
• /
• pp.1113-1120
• /
• 2014

In this paper, general methods for enhancing the transmission efficiency through the small subwavelength aperture in an infinite conducting plane are considered first by use of the transmission-resonant aperture like the ridged circular aperture structure, second by employing the transmission-resonant cavity structure. In particular, the maximum transmission cross section is found to be $\frac{2G{\lambda}^2}{4{\pi}}[m^2]$ for the two structures, where G is the gain of the aperture in the output half space. As experimental works, the impedance matching characteristics are investigated for the cases that above two structures are incorporated as a potential near field microscopic probe in the waveguide end. As a complementary problem to the above transmission-resonant aperture problem, some discussions are also given on the scattering resonance by the scattering object much smaller than the wavelength. This discussion may provide a good understanding of the physics for the phenomena that the maximum scattering cross section is much larger than the physical size of the atom in atomic physics area.