• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.149-150
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• 2011

• 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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.2
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• pp.80-84
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• 2018

In this study, we investigated plasmon effects to maximize the sterilization of dielectric discharge. We predicted the effect using the finite difference time domain (FDTD) method as a function of electrode shape, size, and period. The structure of the electrode was designed with a thickness of 100 nm of silver nanoparticles on a glass substrate, and was varied according to the shape, size, and period of the electrode hole. Based on the results, it was confirmed that the effect of plasmons was independent of the shape of the electrode hole. It was thus confirmed that the plasmon effect depended only on the size and period of the holes. Further, the plasmon effect was affected by the size rather than period of the holes. Because the absorption of light by the metal varied according to the size of the hole, the plasmon effect generated by the absorption of light also varied. The best results were obtained when the radius and period of the electrode holes were $0.1{\mu}m$ and $0.4{\mu}m$, respectively.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.160-165
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• 2006

We have designed a high-transmission nano aperture in a perfect electric conductor film with the incident beam of 532 nm wavelength. The aperture basically has a C-shape and is known to produce a bright spot nearby the aperture in small size less than diffraction limit. The bright spot is strongly coupled with the local plasmon excited through the aperture hole. The characteristics of transmission and peak power of the aperture output were calculated using finite differential time domain (FDTD) technique, and the geometry of the aperture was determined to get a maximum transmission and peak power. To find the effect of the surface plasmon induced near by the aperture, we calculated the variations of the transmittance and the beam sizes by changing the size of the input beam irradiated on the aperture.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.247-247
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• 2012

Plasmon subwavelength nanostructures enable the structurally modulated color due to the resonance conditions for the specific wavelength range of light with the nanoscale hole arrays on a metal layer. While the unique properties offered from a single layer of metal may open up the potential applications of integrated devices to displays and sensors, fabrication requirements in nanoscale, typically on the order of or smaller than the wavelength of light in a corresponding medium can limit the cost-effective implementation of the plasmonic nanostructures. Simpler nanoscale replication technologies based on the soft lithography or roll-to-roll nanoimprinting can introduce economically feasible manufacturing process for these devices. Such replication requires an optimal design of a master template to produce a stamp that can be applied for a roll-to-roll nanoimprinting. In this paper, a master mold with subwavelength nanostructures is fabricated and optimized using focused ion beam for the applications to nanoimprinting process. Au thin film layer is deposited by sputtering on a glass that serves as a dielectric substrate. Focused ion beam milling (FIB, JEOL JIB-4601F) is used to fabricate surface plasmon subwavelength nanostructures made of periodic hole arrays. The light spectrum of the fabricated nanostructures is characterized by using UV-Vis-NIR spectrophotometer (Agilent, Cary 5000) and the surface morphology is measured by using atomic force microscope (AFM, Park System XE-100) and scanning electron microscope (SEM, JEOL JSM-7100F). Relationship between the parameters of the hole arrays and the corresponding spectral characteristics and their potential applications are also discussed.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.4
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• pp.293-300
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• 2001

A polyrotaxane-biotin conjugate was synthesized and its interaction with streptavidin measured using surface plasmon resonance(SPR) detection. A biodegradable polyrotaxane in which ca, 22 molecules of ${\alpha}$-cyclodextrina(${\alpha}$-CDs) were threaded onto a poly(ethylene oxide) chain(M$\sub$n:4,000) capped with benzyloxycarbonyl-L-phenylalanine was conjugated with a biotin hydorazide and 2-aminoethanol after activing the hydroxyl groups of ${\alpha}$-CDs in the polyrotaxane using N, N'-carbonyldiimidazole. The results of the high-resolution $^1$H-nyclear lmagnetic resonance($^1$H-NMR)spectra and gel permeation chromatography of the conjugate showed that ca, 11 biotin molecules were actually introduced to the polyrotaxane scaffold. An SPR analysis showed that the binding curves of the biotin molecules in the conjugate on the streptavidin-deposited surface changed in a concentration dependent manner, indicating that the biotin in the conjugate was ac-tually recognized by streptavidin. The association equilibrium constant(K$\sub$a/) of the interaction be-tween the conjugate and steptavidin tetramer was of the order 10$\^$7/. These results suggest that polyrotaxane is useful for scaffolds as a polymeric ligand in biomedical fields.

• Journal of Sensor Science and Technology
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• v.28 no.6
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• pp.355-359
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• 2019

Exosomes, known as nanoscale extracellular vesicles in the range of 30-150 nm, are known to contain clinically significant information. However, there is still insufficient information on exosomal membrane proteins for cancer diagnosis. In this work, we investigated the characteristics of the membrane proteins of exosomes shed by cultured breast cancer cell lines using a surface plasmon resonance (SPR) spectroscopy and pre-activated alkanethiols modified sensor chips. The antibodies of breast cancer biomarkers such as MCU-16, EpCAM, CD24, ErbB2, and CA19-9 were immobilized on the pre-activated alkanethiols surfaces without any activation steps. The purified exosomes were loaded onto each antibody surface. The affinity rank of the antibody surfaces was decided by the relative capture efficiency factors for the exosomes. In addition, an antibody with a relative capture efficiency close to 100% was tested with exosome concentration levels of 10⁴/µl, 10⁵/µl, and 10⁶/µl for quantitative analysis.

• 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.

• Journal of Biosystems Engineering
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• v.35 no.2
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• pp.116-123
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• 2010

Rapid detection of foodborne pathogens has been a major challenge for the food industry. Salmonella contamination is well known in all foods including pasteurised milk. The possibility of specific detection of Salmonella Enteritidis by surface plasmon resonance (SPR) biosensor was explored using a commercially available portable SPR sensor. Self assembly technique was adopted to immobilize anti-Salmonella antibodies on the gold sensing surface of the SPR sensor. The concentration of polyclonal antibody for use in the SPR biosensor was chosen to 1.0 mg/mL. Experiments were conducted at near real-time with results obtained for one SPR biosensor assay within 1 hour. The limit of detection for Salmonella Enteritidis was determined to be $10^6$ CFU/mL in both PBS buffer and milk samples. The assay sensitivity was not significantly affected by milk matrix. Our results showed that it would be possible for employing the SPR biosensor to detect Salmonella Enteritidis in near real-time.

• Journal of Sensor Science and Technology
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• v.30 no.5
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• pp.326-330
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• 2021

Reactions between gold (Au) surface plasmon resonance (SPR) chips and bovine serum albumin (BSA) dissolved in solutions of different pH were investigated. The charge on the BSA depends on the pH of the solution in which it is dissolved. Thus, dissolving BSA in different pH solutions resulted in different charges of BSA. Among the BSA dissolved in solutions with pH 4.01, 7.4, and 10.01, the SPR response was the highest for BSA dissolved in the solution of pH 4.01. To eliminate the response variation owing to the difference in the refractive indices of the solutions, phosphate buffered saline (PBS) was injected into the system after the reaction of BSA with the Au SPR chip had happened. In this case too, the BSA dissolved in the solution with pH 4.01 exhibited the highest response. This may be attributed to the non-uniform distribution of ionic patches on the BSA, which can induce electrostatic attraction to the surface even though BSA has a positive charge at pH 4.01, and the absolute values of the net charge of BSA at pH 4.01 and 7.4 were very close.