• Korean Journal of Optics and Photonics
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• v.12 no.6
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• pp.437-445
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• 2001

We examine theoretically the properties of the force on Mie particles induced by evanescent fields at a system of multilayer films (including a metal film), at which the surface plasmon resonance is excited by a p-polarized plane electromagnetic wave. An expression of the surface plasmon-coupled evanescent fields produced in Kretschmann (or Sarid) geometry is expanded in terms of vector spherical wave functions, while multiple reflections between the Mie particle and the metal boundary are taken into account. The Cartesian components of the force on Mie particles by the evanescent fields are analytically formulated and numerically evaluated. The force components are increased by one or two orders of magnitude at metal boundaries over those at dielectric boundaries. As a result, we can confirm the possibility of stable manipulation or rotation of a finite-sized object by forces of surface plasmon-coupled evanescent fields.

• Proceedings of the Korean Vacuum Society Conference
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• 2008.02a
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• pp.91-91
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• 2008

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.793-800
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• 2013

A few years ago, the plasmon-induced electronic coupling (PIEC) model was proposed in the literature to explain small changes in the surface-enhanced Raman scattering (SERS) in nanogap systems. If this model is correct, it will be very helpful in both basic and application fields. In light of this, we carefully reexamined its appropriateness. Poly(4-vinylpyridine) (P4VP) used in the earlier work was, however, never a proper layer, since most adsorbates not only adsorbed onto Ag nanoparticles sitting on P4VP but also penetrated into the P4VP layer deposited initially onto a flat Ag substrate, ultimately ending up in the SERS hot sites. Using 1,4-phenylenediisocyanide and 4-nitrophenol as the affixing layer and the foreign adsorbate, respectively, we could clearly reveal that the PIEC model is not suited for explaining the Raman signal in a nanogap system. Most of the Raman signal must have arisen from molecules situated at the gap center.

• Carbon letters
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• v.25
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• pp.84-88
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• 2018

At present, an important research area is the search for materials that are compatible with CMOS technology and achieve a satisfactory response rate and modulation efficiency. A strong local field of graphene surface plasmon polariton (SPP) can increase the interaction between light and graphene, reduce device size, and facilitate the integration of materials with CMOS. In this study, we design a new modulator of SPP-based cycle branch graphene waveguide. The structure comprises a primary waveguide of graphene-$LiNbO_3$-graphene, and a secondary cycle branch waveguide is etched on the surface of $LiNbO_3$. Part of the incident light in the primary waveguide enters the secondary waveguide, thus leading to a phase difference with the primary waveguide as reflected at the end of the branch and interaction coupling to enhance output light intensity. Through feature analysis, we discover that the area of the secondary waveguide shows significant localized fields and SPPs. Moreover, the cycle branch graphene waveguide can realize gain compensation, reduce transmission loss, and increase transmission distance. Numerical simulations show that the minimum effective mode field area is about $0.0130{\lambda}^2$, the gain coefficient is about $700cm^{-1}$, and the quality factor can reach 150. The structure can realize the mode field limits of deep subwavelength and achieve a good comprehensive performance.

• Korean Journal of Optics and Photonics
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• v.5 no.2
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• pp.311-318
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• 1994

We fabricated fiber-optic polarizers utilizing polarization selective mode coupling between the guided mode of a fiber and the surface plasmon mode supported by a thin aluminium film deposited on the polished side of a fiber. AI thin films with various thicknesses were coated onto the 633 nm, 830 nm, 1.3 fJITI single mode fibers. The maximum extinction ratio was higher than 30 dB for most of the samples and the best result was 42 dB at 90 A film thickness, with 1.3 fJITI single mode fiber. The insertion loss ranged from 0.2 dB to 1.5 dB.1.5 dB.

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.125-126
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• 2008

We investigate characteristics of gold and silver metal strip waveguides based on long range surface plasmon polaritons (LRSPPs) along thin metal strips embedded in a polymer for practical applications at the wavelengths of 1.31 and 1.55 um. Guiding properties of the metal strip waveguides are theoretically and experimentally evaluated. In addition, surrounding technologies such as the development of TM-mode laser, coupling properties, as well as high-speed digital signal transporting experiments will be explained for board-to-board optical interconnections by using the LRSPP waveguides.

• Korean Journal of Optics and Photonics
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• v.17 no.4
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• pp.371-380
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• 2006

We design and fabricate a novel tunable wavelength filter, which utilizes long-range surface plasmon-polaritons excited along nm-thick-metal strips. A gold metal strip, with $\sim$ cm length, 20 nm thickness, and $\sim$ 5$\mu$m width, is embedded in thick thermo-optic Polymer films supported by a silicon wafer. A dielectric Bragg grating structure is Placed on the metal strip, so that transmission signals at telecom wavelength are selected by thermal effect of the thermo-optic polymer. High extinction ratio of 25 dB and total insertion loss of $\sim$25 dB/cm can be measured by single-mode coupling of optical fibers. We also verify that wavelength tuning of the long-range surface plasmon-polariton filters can be achieved by electric current directly applied to the metal-strip waveguides.

• Current Optics and Photonics
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• v.5 no.1
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• pp.1-7
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• 2021

For higher sensitivity in ultraviolet (UV) and even vacuum ultraviolet (VUV) detection of silicon-based sensors, a sandwich-structured film sensor based on Ag Localized Surface Plasmon Resonance (LSPR) was designed and fabricated. This film sensor was composed of a Ag nanoparticles (NPs) layer, SiO2 buffer and fluorescence layer by physical vapour deposition and thermal annealing. By tuning the annealing temperature and adding the SiO2 layer, the resonance absorption wavelength of Ag NPs matched with the emission wavelength of the fluorescence layer. Due to the strong plasmon resonance coupling and electromagnetic field formed on the surface of Ag NPs, the radiative recombination rate of the luminescent materials and the number of fluorescent molecules in the excited state increased. Therefore, the fluorescent emission intensity of the sandwich-structured film sensor was 1.10-1.58 times at 120-200 nm and 2.17-2.93 times at 240-360 nm that of the single-layer film sensor. A feasible method is provided for improving the detection performance of UV and VUV detectors.

• BMB Reports
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• v.55 no.3
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• pp.111-112
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• 2022

We visualized the distribution of heterochromatin in a single nucleus using plasmonic nanoparticle-conjugated H3K9me3 and H3K27me3 antibodies. Due to distance-dependent plasmonic coupling effects between nanoprobes, their scattering spectra shift to longer wavelengths as the distance between heterochromatin histone markers reduced during oncogene-induced senescence (OIS). These observations were supported by simulating scattering profiles based on considerations of particle numbers, interparticle distances, and the spatial arrangements of plasmonic nanoprobes. Using this plasmon-based colourimetric imaging, we estimated changes in distances between H3K9me3 and H3K27me3 during the formation of senescence-associated heterochromatin foci in OIS cells. We anticipate that the devised analytical technique combined with high-spatial imaging and spectral simulation will eventually lead to a new means of diagnosing and monitoring disease progression and cellular senescence.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.76-76
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• 2008

The resonance properties due to the surface plasmon(SP) excitation of metal nanoparticles make the nanocomposite films promising for various applications such as optical switching devices. In spite of the well-known ultra-sensitive operation of optical switches based on a guided wave, the application of nanocomposite film(NC) has inherent limitation originating from the excessive optical loss related with the surface plasmon resonance(SPR). In this study, we addressed this problem and present the experimental and theoretical analysis on the pump-probe optical switching in prism-coupled Au(1 vol.%):$SiO_2$ nanocomposite waveguide film. The guided mode was successfully generated using a near infrared probe beam of 1550 nm and modulated with an external pump beam of 532 nm close to the SPR wavelength. We extend our approach to ultra-fast operation using a pulsed laser with 5 ns pulse width. To improve the switching speed through the reduction in thermal loading effect accompanied by the resonant absorption of pump beam light, we adopted a metallic film as a coupling layer instead of low-index dielectric layer between the high-index SF10 prism and NC slab waveguide. We observed great enhancement in switching speed for the case of using metallic coupling layer, and founded a distinct difference in origin of optical nonlinearities induced during switching operation using cw and ns laser.