• Korean Journal of Materials Research
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• v.24 no.8
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• pp.417-422
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• 2014

In this study, we investigated localized surface plasmon resonance and the related coupling phenomena with respect to various geometric parameters of Ag nanoparticles, including the size and inter-particle distance. The plasmon resonances of Ag nanoparticles were studied using three-dimensional finite difference time domain(FDTD) calculations. From the FDTD calculations, we discovered the existence of a symmetric and an anti-symmetric plasmon coupling modes in the coupled Ag nanoparticles. The dependence of the resonance wavelength with respect to the inter-particle distance was also investigated, revealing that the anti-symmetric mode is more closely correlated with the inter-particle distance of the Ag nanoparticles than the symmetric mode. We also found that higher order resonance modes are appeared in the extinction spectrum for closely spaced Ag nanoparticles. Plasmon resonance calculations for the Ag particles coated with a $SiO_2$ layer showed enhanced plasmon coupling due to the strengthened plasmon resonance, suggesting that the inter-particle distance of the Ag nanoparticles can be estimated by measuring the transmission and absorption spectra with the plasmon resonance of symmetric and anti-symmetric localized surface plasmons.

• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.33-34
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• 2013

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.111-111
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• 2012

In this talk, we represent a novel approach to investigating intra-nanorod surface plasmon coupling with control over block compositions. The multi-component rod-like nanostructures, which consist of optically active components (Au and Ag) and optically less active component (for example, Ni) in UV-vis-NIR spectral window, showed interesting optical response depending on each block length and the total length of the structure. By controlling the composition and relative lengths of the blocks that comprise these structures, we can tailor the overall optical properties. Depending on the relative fraction of Au and Ag blocks, the intensity of the transverse modes varied without noticeable peak shifts. However, the strong intraparticle surface plasmon coupling resulted in the collective appearance of longitudinal LSP modes, including higher-order modes. The experimental observations were confirmed by theoretical calculation, using a discrete dipole approximation method. In addition, we will briefly discuss how single nanorod solar cells can be synthesized by using by using electrochemical deposition and AAO hard templates.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.180-181
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• 2002

Abstract. A surface plasmon resonance based on a ion-exchange glass waveguide investigated. we analyzed resonant coupling between TM-plarized waveguide mode and surface plasmon wave.

• Journal of the Korean Physical Society
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• v.73 no.9
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• pp.1283-1288
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• 2018

In this work, we investigate polarization-dependent excitation of the propagating surface plasmon polariton (SPP) modes in gold nanowires (Au NWs) combined with gold nanoparticles (Au NPs). The light coupling from focused light to SPPs on Au NWs is investigated for different structural combinations of Au NWs with Au NPs, using full-wave finite-element numerical simulations. The results show that the excitation of SPPs changes remarkably on varying the orientation of the NP on NW or the polarization angle of the incident light. Metallic NWs combined with NPs can be applied to the polarization-resolved SPP coupling in various optical and optoelectronic devices including photonic circuits and optical sensors.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.4
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• pp.795-800
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• 2009

Surface plasmon resonance (SPR) has been widely used for biological and chemical sensing applications. The present study investigates numerically the optical characteristics for the single Au film and bimetallic Ag/Au film SPR configurations by using the multiple beam interference matrix (MBIM) method. We use the prism coupling method, especially Kretschmann configuration for excitation of surface plasmon wave (SPW). The estimated results of reflectance, phase shift and magnetic field intensity enhancement factor are provided for finding out the optimum configuration with high sensitivity for SPR measurement. As a result, the optimum thicknesses are found to be 52 nm for a single Au film and 5 nm to 36 nm for bimetallic Ag-Au film. From the comparison of full width half maximum (FWHM) values for reflectance, phase shift, and enhancement of magnetic field intensity, it is concluded that the highest sensitivity can be obtained when using the phase shift for SPR sensor.

• Current Optics and Photonics
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• v.6 no.5
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• pp.497-505
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• 2022

Topological photonic nanocavities are considered to possess outstanding optical performance, and provide new platforms for realizing strong interaction between light and matter, due to their robustness to impurities and defects. Here hybrid plasmonic topological photonic nanocavities are proposed, by embedding various plasmon nanoantennas such as gold nanospheres, cylinders, and rectangles in a topological photonic crystal corner-state nanocavity. The maximum quality factor Q and minimum effective mode volume V_eff of these hybrid nanocavities can reach the order of 10⁴ and 10^-4 (𝜆/n)³ respectively, and the high figures of merit Q/V_eff for all of these hybrid nanocavites are stable and on the order of 10⁵ (𝜆/n)^-3. The relative positions of the plasmon nanoantennas will influence the coupling strength between the plasmon structures and the topological nanocavity. The hybrid nanocavity with gold nanospheres possesses much higher Q, but relatively large V_eff. The presence of a gold rectangular structure can confine more electromagnetic energy within a smaller space, since its V_eff is smallest, although Q is lowest among these structures. This work provides an outstanding platform for cavity quantum electrodynamics and has a wide range of applications in topological quantum light sources, such as single-photon sources and nanolasers.

• Journal of the Semiconductor & Display Technology
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• v.8 no.3
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• pp.7-11
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• 2009

In this paper, we developed and presented a design result for optimizing the geometry of Ag circular SPP waveguide for subwavelength waveguide applications. We investigated the effect of the design parameters on the light propagation and find the optimum design for small modal size, high coupling coefficient, and low sensitivity. The results show that the globally optimal design locates optimal waveguide geometries more efficiently than individual optimal points for multivalued objective function.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.76.2-76.2
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• 2015

I will present my research group's recent investigation on how the localized plasmon of a nanoparticle interacts with another plasmon, and with nearby molecules. First, I will demonstrate the use of scattering-type scanning near-field microscopy (s-SNOM) to directly visualize the capacitive / conductive coupling in dimeric nanoparticles and heterometallic nanorods. Second, I will talk about the use of gap-plasmons to locally induce photochemical reactions, and to follow chemical kinetics of individual organic molecules using the gap-plasmons. As a last topic, I will talk about the use of near-field coupling between a scanning probe and graphenes to visualize / identify the stacking domains (e. g., ABA versus ABC-type stacking in triple layer) hidden in multilayer graphenes.

• Journal of Sensor Science and Technology
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• v.28 no.4
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• pp.262-265
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• 2019

The effect of inter-band transition on surface plasmon resonance in gold thin film was investigated. We induced localized inter-band transition in the film by using incident light on its surface from a green laser (532 nm) source, and the surface plasmon resonance for inter-band transition was investigated at different wavelengths. It was determined that the reflectivity of blue light (450 nm) was significantly reduced in the region where the green laser was incident. We demonstrated that this decrease is mainly due to the coupling between the blue light and the surface plasmon resonance of excited electrons in higher energy states, based on experimental results for the incident and polarization angle-dependent reflectivity of the blue light.