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322 results on '"Oh, Sang-Hyun"'

22. Bandgap engineering of two-dimensional semiconductor materials

Author

Chaves, A., Azadani, J. G., Alsalman, Hussain, da Costa, D. R., Frisenda, R., Chaves, A. J., Song, Seung Hyun, Kim, Y. D., He, Daowei, Zhou, Jiadong, Castellanos-Gomez, A., Peeters, F. M., Liu, Zheng, Hinkle, C. L., Oh, Sang-Hyun, Ye, Peide D., Koester, Steven J., Lee, Young Hee, Avouris, Ph., Wang, Xinran, and Low, Tony

Published
2020
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24. Nanoscale tweezers for single-cell biopsies

Author

Nadappuram, Binoy Paulose, Cadinu, Paolo, Barik, Avijit, Ainscough, Alexander J., Devine, Michael J., Kang, Minkyung, Gonzalez-Garcia, Jorge, Kittler, Josef T., Willison, Keith R., Vilar, Ramon, Actis, Paolo, Wojciak-Stothard, Beata, Oh, Sang-Hyun, Ivanov, Aleksandar P., and Edel, Joshua B.

Published
2019
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31. Promises and challenges of nanoplasmonic devices for refractometric biosensing

Author

Dahlin Andreas B., Wittenberg Nathan J., Höök Fredrik, and Oh Sang-Hyun

Subjects
optical biosensors, refractometric sensors, surface plasmon resonance, plasmonics, figure of merit, single molecule detection, enzyme-linked biosensing, site-specific chemistry, supported lipid bilayer, pore-spanning lipid membrane, nanoparticle, nanohole, optofluidics, Physics, QC1-999
Abstract

Optical biosensors based on surface plasmon resonance (SPR) in metallic thin films are currently standard tools for measuring molecular binding kinetics and affinities – an important task for biophysical studies and pharmaceutical development. Motivated by recent progress in the design and fabrication of metallic nanostructures, such as nanoparticles or nanoholes of various shapes, researchers have been pursuing a new generation of biosensors harnessing tailored plasmonic effects in these engineered nanostructures. Nanoplasmonic devices, while demanding nanofabrication, offer tunability with respect to sensor dimension and physical properties, thereby enabling novel biological interfacing opportunities and extreme miniaturization. Here we provide an integrated overview of refractometric biosensing with nanoplasmonic devices and highlight some recent examples of nanoplasmonic sensors capable of unique functions that are difficult to accomplish with conventional SPR. For example, since the local field strength and spatial distribution can be readily tuned by varying the shape and arrangement of nanostructures, biomolecular interactions can be controlled to occur in regions of high field strength. This may improve signal-to-noise and also enable sensing a small number of molecules. Furthermore, the nanoscale plasmonic sensor elements may, in combination with nanofabrication and materials-selective surface-modifications, make it possible to merge affinity biosensing with nanofluidic liquid handling.

Published
2013
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38. Toward Monoatomic-Layer Field Confinement Limit via Acoustic Graphene Plasmons

Author

Lee, In-Ho, Low, Tony, Martín-Moreno, Luis, Avouris, Phaedon, and Oh, Sang-Hyun

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Physics::Atomic and Molecular Clusters, FOS: Physical sciences, Physics::Optics, Optics (physics.optics), Physics - Optics
Abstract

Vertical plasmonic coupling in double-layer graphene leads to two hybridized plasmonic modes: optical and acoustic plasmons with symmetric and anti-symmetric charge distributions across the interlayer gap, respectively. However, in most experiments based on far-field excitation, only the optical plasmons are dominantly excited in the double-layer graphene systems. Here, we propose strategies to selectively and efficiently excite acoustic plasmons with a single or multiple nano-emitters. The analytical model developed here elucidates the role of the position and arrangement of the emitters on the symmetry of the resulting graphene plasmons. We present an optimal device structure to enable experimental observation of acoustic plasmons in double-layer graphene toward the ultimate level of plasmonic confinement defined by a monoatomic spacer, which is inaccesible with a graphene-on-a-mirror architecture.

Published
2020

39. Graphene plasmon-phonon coupled modes at the exceptional point

Author

Park, Sang Hyun, Xia, Shengxuan, Oh, Sang-Hyun, Avouris, Phaedon, and Low, Tony

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), FOS: Physical sciences
Abstract

Properties of graphene plasmons are greatly affected by their coupling to phonons. While such coupling has been routinely observed in both near-field and far-field graphene spectroscopy, the interplay between coupling strength and mode losses, and its exceptional point physics has not been discussed. By applying a non-Hermitian framework, we identify the transition point between strong and weak coupling as the exceptional point. Enhanced sensitivity to perturbations near the exceptional point is observed by varying the coupling strength and through gate modulation of the graphene Fermi level. Finally, we also show that the transition from strong to weak coupling is observable by changing the incident angle of radiation., 7 pages, 4 figures

Published
2020

42. Plasmonic nanoholes in a multichannel microarray format for parallel kinetic assays and differential sensing

Author

Im, Hyungsoon, Lesuffleur, Antoine, Lindquist, Nathan C., and Oh, Sang-Hyun

Subjects
Plasmons (Physics) -- Properties, Nanotechnology -- Research, Microfluidics -- Research, Fluidic devices -- Properties, Molecular dynamics -- Research, Resonance -- Research, Protein microarrays -- Properties, Biosensors -- Design and construction, Biosensors -- Properties, Chemistry
Abstract

We present nanohole arrays in a gold film integrated with a six-channel microfluidic chip for parallel measurements of molecular binding kinetics. Surface plasmon resonance effects in the nanohole arrays enable real-time, label-free measurements of molecular binding events in each channel, while adjacent negative reference channels can record measurement artifacts such as bulk solution index changes, temperature variations, or changing light absorption in the liquid. With the use of this platform, streptavidin--biotin specific binding kinetics are measured at various concentrations with negative controls. A high-density microarray of 252 biosensing pixels is also demonstrated with a packing density of 106 sensing elements/[cm.sup.2], which can potentially be coupled with a massively parallel array of microfluidic channels for protein microarray applications.

Published
2009

43. Attenuation mechanism effect on filter shape in channelized dynamic spectral equalizers

Author

Oh, Sang-Hyun and Marom, Dan M.

Subjects
Optics, Astronomy, Physics
Abstract

Free-space-based channelized dynamic spectral equalizers are theoretically investigated by solving the temporal-frequency-dependent power-coupling integral for commonly used active device technologies: liquid-crystal modulators, tilting micromirror arrays, and deformable gratings. Channel-filter characteristics, such as bandwidth and interchannel transition, are found to depend on the different attenuation mechanisms provided by the active devices. Such information is required for choosing the proper device parameters in designing channel equalizers and similar free-space spatially dispersed subsystems. OCIS codes: 060.2340, 070.6110, 230.6120, 010.1080, 120.2440.

Published
2004

44. Monolithic fringe-field-activated crystalline silicon tilting-mirror devices

Author

Greywall, Dennis S., Pai, Chien-Shing, Oh, Sang-Hyun, Chang, Chorng-Ping, Marom, Dan M., Busch, Paul A., Cirelli, Raymond A., Taylor, Ashley J., Klemens, Fred P., Sorsch, Thomas W., Bower, John Eric, Lai, Warren Y.-C., and Soh, Hyongsok T.

Subjects
Microelectromechanical systems -- Research, Engineering and manufacturing industries, Science and technology
Abstract

A new approach is presented for fabricating monolithic crystalline silicon tilting-mirror microoptoelectromechanical systems (MOEMS) devices. The activation electrodes, etched from a thick silicon layer deposited over insulating oxide onto the top surface of a silicon-on-insulator (SOI) wafer, are displaced from the mirrors and interact with these tilting elements via electrostatic fringing fields. In contrast to the more usual parallel-plate activation, the rotation angle saturates at high voltages. This paper discusses concept, design, and processing, and also compares modeling and measured performance of a specific 9[degrees] tilt range device array. [977] Index Terms--MEMS, MOEMS, micromachined structures, optical telecommunications.

Published
2003

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