• Korean Journal of Optics and Photonics
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• v.2 no.2
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• pp.59-66
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• 1991

Resonance angle and optimum thinckness of various thin metal films for surface plasmon resonance were calculated using an admittance diagram and optical constants and thickness of thin Ag films and Al films were determined by fitting the measured reflectance of surface plasmon resonance. Two wavelengths of an Ar ion laser were employed to select the unique optical constants which have the same thickness at two wavelengths. Also, when these films were exposed to the air, the shift of surface plasmon resonance was measured and the optical constants of modified thin films were determined.

• Korean Journal of Optics and Photonics
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• v.3 no.4
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• pp.205-216
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• 1992

Distribution of electric fields of surface plasmons at resonance and off-resonance angles were calculated and compared. As applications of surface plasmon resonance, (1) optical constants of ZnS films overcoated on Ag films were measured as the thickness of ZnS films increased, (2) four surface plasmon resonances distributed spatially due to the different thickness of SiO thin films overcoated on Ag films were observed in a picture frame by employing diverging waves of incidence, and (3) patterns of SiO thin films such as a grating and a character "가" overcoated on Ag films were measured by employing collimated waves of incidence.

• Korean Journal of Optics and Photonics
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• v.25 no.2
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• pp.95-101
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• 2014

When voltage is applied on the metal layer of a surface plasmon resonance (SPR) sensor, electric field excitation causes charge accumulation on the metal surface. This alters not only the optical properties of the metal but also the SPR angle. In this study we investigate this effectby performing experiments using solutions of various pH values, and we obtain the relation between total surface charge and SPR angle. The curves for the various pH conditions become coincident. We compare our results to those from an earlier space charge layer (SCL) model, and suggest a modified SCL model which explains our result well. This result will be useful in applications of SPR sensors, and in studying the optical properties of thin metal layers.

• Proceedings of the Optical Society of Korea Conference
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• 1991.06a
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• pp.90-93
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• 1991

일곤 레이저의 두 파장(488 nm, 514.5 nm)을 사용하여 은 박막과 은 박막 위에 덧증착한 ZnS 박막의 유일한 광학 상수와 두께를 Kretschmann 구조의 표면 플라즈몬 공명을 이용하여 결정하였다.

• Korean Journal of Optics and Photonics
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• v.15 no.1
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• pp.51-55
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• 2004

Surface plasmons (SPs) are charge density oscillations that propagate along an interface between a dielectric and metal. In this paper, the electric field of SPs and the intereference of two SPs are observed by using Near-field Scanning Optical Microscope (NSOM). The excitation condition of SPs is changed as the optical tip approaches the metal surface, because the excitation condition of SPs is very sensitive to surface structures. To measure the microscope field of SPs, the distance between metal surface and optical tip must contain a specific interval.

• Korean Journal of Optics and Photonics
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• v.33 no.4
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• pp.177-186
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• 2022

The performance of a surface plasmon resonance sensor is evaluated based on the sensitivity (nm/RIU) and sharpness from the full width at half maximum (FWHM) and the peak depth of a resonance peak. These factors are determined by the materials and conformational properties of the sensing structure. In this paper, we investigated an optimized insulator-metal-insulator (IMI) multilayer-based surface plasmon resonance sensor structure to simultaneously achieve high sensitivity, narrow FWHM, and deep peak depth while using gold for the metallic film layer which occurs peak broadening. By adopting the optimized structure, sensitivity of 8,390 nm/RIU, FWHM of 11.92 nm, and a resonance peak depth of 93.1% were achieved for 1.45-1.46 refractive index variation of the sensing layer. With the suggested structure conformation, high sensitivity and resolution of sensing performance can be achieved.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.80-80
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• 2008

바이오 센서 응용 연구에 많이 사용되는 금(Au) 나노 입자를 이용한 국소 표면 플라즈몬 공명(Localized Surface Plasmon Resonance, LSPR)에 의한 산란광을 검출하는데 주로 이용되는 암시야(dark field) 현미경 검출 방식에 관한 전산모사를 통하여 입사광의 입사 방식에 따른 산란광 세기를 정량적으로 분석하였다. 전산모사 기법으로는 국소 표면 플라즈몬 공명의 동역학적인 현상을 모사할 수 있는 유한차분시간영역(Finite Difference Time Domain, FDTD) 기법을 이용하였는데, 이러한 기법이 암시야 현미경 전산 모사에 유효함을 우선적으로 검증하였다. 암시야 현미경 검출 방식의 모사에서 입사 광원의 반사 입사 방식과 투과 입사 방식을 비교하였고, 각각의 방식에 서 입사광의 입사각에 따른 산랑광 세기를 계산하였다. 이러한 전산모사를 통하여 프리즘을 통한 내부 전반사(Total Internal Reflection, TIR) 방식에서 입사 광원의 임계각 근처에서 많이 발생하는 에바네슨트 장(evanescent field)을 결합하는 경우 산란광 세기가 증가함을 관찰하였고, 이러한 세기의 변화를 프레넬(Fresnel) 방정식에 의해 계산된 에바네슨트 장의 세기 분포와 비교 분석하였다.

• Korean Journal of Optics and Photonics
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• v.29 no.5
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• pp.215-219
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• 2018

In this paper we show that the localized surface-plasmon resonance of Ag nanoparticles produced by laser dewetting can be effectively utilized for improving the photocurrent and efficiency of a dye-sensitized $TiO_2$ solar cell. An Ag thin film deposited on a conducting glass substrate was dewetted into nanoparticles by a pulsed laser. A dye-sensitized $TiO_2$ solar cell fabricated on this substrate containing the Ag nanoparticles exhibited improved photovoltaic performance, compared to a reference cell. This is attributed to the increased light trapping that arises from the localized surface-plasmon resonance of the dewetted Ag nanoparticles.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.88-93
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• 2017

It is important to develop a simple method oftuning localized surface plasmon resonance(LSPR) properties, due to their numerous applications. In addition, the careful examination of the shape, size and combination of metal nanoparticles is useful for understanding the relation between the LSPR properties and metal nanostructures. This article describes the dependence of theLSPR properties on the arrays of metal nanoparticles obtained from a block copolymer(BCP) micellar thin film. Firstly, two different Au nanostructures, having a dot and ring shape, were fabricated using conventional block copolymer micelle lithography. Then, Ag was plated on the Au nanostructures through the silver mirror reaction technique to obtain Au/Ag bimetallic nanostructures. During the production of these metallic nanostructures, the processing factors, such as the pre-treatment by ethanol, silver mirror reaction time and removal or not of the BCP, were varied. Once the Au nanoparticles were synthesized, Ag was properly plated on the Au, providing two distinguishable characteristic plasmonic bands at around 525nm for Au and around 420nm for Ag, as confirmed bythe UV-vis measurements. However, when a small amount of Au seed nanoparticles, which accelerate the Ag plating speed,was formed by usinga block copolymer with a relatively highmolecular weight, all of the Au surfaces were fully covered by Ag during the silver mirror reaction, showing only the characteristic peak for Ag at around 420nm. The Ag plating technique on Au nanoparticles pre-synthesized from a block copolymer is useful to study the LSPR properties carefully.

• Korean Journal of Optics and Photonics
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• v.13 no.1
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• pp.9-14
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• 2002

A surface plasmon sensor has been fabricated for detection of concentration and refractive-index of a mixed solution. Based on the Kretschmann-Raether attenuated-total-reflection configuration, the sensor consists of 54 nm-thick Ag metal layer under a prism and a cell containing the mixed solution. We have observed a nonlinear refractive-index change as the ethanol-water concentration increased. The experimental results show us that the detection limit of the SPR sensor is 3$\times$10$^{-2}$ % in ethanol mass ratio. The concentration-to-index curve shows a linear increase in the range of ethanol concentration from 0% to 50%, but a nonlinearity is observed beyond 50%. We have modeled the nonlinearity and compared it with the experimental results.