38 results on '"Jangwoon Sung"'
Search Results
2. Design of highly perceptible dual-resonance all-dielectric metasurface colorimetric sensor via deep neural networks
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Hyunwoo Son, Jongwoo Hong, Sun-Je Kim, Jangwoon Sung, and Byoungho Lee
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Materials science ,Multidisciplinary ,business.industry ,Resonance ,Dielectric ,DUAL (cognitive architecture) ,Surface Plasmon Resonance ,Nanostructures ,Excipients ,Refractometry ,Colorimetric sensor ,Optoelectronics ,Deep neural networks ,Colorimetry ,Neural Networks, Computer ,business - Abstract
Colorimetric sensing, which provides effective detection of bio-molecular signals with one’s naked eye, is an exceptionally promising sensing technique in that it enables convenient detection and simplification of entire sensing system. Though colorimetric sensors based on all-dielectric nanostructures have potential to exhibit distinct color variations enabling manageable detection due to their trivial intrinsic loss, there is crucial limitation that the sensitivity to environmental changes lags behind their plasmonic counterparts because of relatively small region of near field-analyte interaction of the dielectric Mie-type resonator. To overcome this challenge, we proposed all-dielectric metasurface colorimetric sensor which exhibits dual-resonance in the visible region. Thereafter, we confirmed with simulation that, in the elaborately designed dual-Lorentzian-type spectra, highly perceptible variations of structural color were manifested even in minute change of peripheral refractive index. In addition to verifying physical effectiveness of the superior colorimetric sensing performance appearing in the dual-resonance type sensor, by combining advanced optimization technique utilizing deep neural networks, we attempted to maximize sensing performance while obtaining dramatic improvement of design efficiency. Through well-trained deep neural network that accurately simulates the input target spectrum, we numerically verified that designed colorimetric sensor shows a remarkable sensing resolution distinguishable up to change of refractive index of 0.0086.
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- 2022
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3. Dynamic phase-change metafilm absorber for strong designer modulation of visible light
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Jeong-Geun Yun, Yohan Lee, Sun Jae Jeong, Chulsoo Choi, Sungwook Choi, Yong Wook Lee, Hansik Yun, Sun-Je Kim, Jongwoo Hong, Kyungsoo Park, Seung-Yeol Lee, Jangwoon Sung, and Byoungho Lee
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phase-change material ,Materials science ,vanadium dioxide ,coupled mode theory ,QC1-999 ,Physics::Optics ,02 engineering and technology ,Coupled mode theory ,metafilm ,01 natural sciences ,Nanomaterials ,010309 optics ,Phase change ,Vanadium dioxide ,effective medium theory ,0103 physical sciences ,Electrical and Electronic Engineering ,business.industry ,Physics ,021001 nanoscience & nanotechnology ,Phase-change material ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,visible light modulation ,Modulation ,Optoelectronics ,0210 nano-technology ,business ,Biotechnology ,Visible spectrum - Abstract
Effective dynamic modulation of visible light properties has been significantly desired for advanced imaging and sensing technologies. In particular, phase-change materials have attracted much attention as active material platforms owing to their broadband tunability of optical dielectric functions induced by the temperature-dependent phase-changes. However, their uses for visible light modulators are still limited to meet multi-objective high performance owing to the low material quality factor and active tunability in the visible regime. Here, a design strategy of phase-change metafilm absorber is demonstrated by making the use of the material drawbacks and extending design degree of freedom. By engineering tunability of effective anisotropic permittivity tensor of VO2-Ag metafilm around near-unity absorption conditions, strong dynamic modulation of reflection wave is achieved with near-unity modulation depth at desired wavelength regions without sacrificing bandwidth and efficiency. By leveraging effective medium theory of metamaterial and coupled mode theory, the intuitive design rules and theoretical backgrounds are suggested. It is also noteworthy that the dynamic optical applications of intensity modulation, coloring, and polarization rotation are enabled in a single device. By virtue of ultrathin flat configuration of a metafilm absorber, design extensibility of reflection spectrum is also verified. It is envisioned that our simple and powerful strategy would play a robust role in development of miniaturized light modulating pixels and a variety of photonic and optoelectronic applications.
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- 2020
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4. Metasurface optics for imaging applications
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Byoungho Lee, Jangwoon Sung, and Gun-Yeal Lee
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Physics ,Diffraction ,Microscope ,business.industry ,Physics::Optics ,Metamaterial ,Ranging ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,law.invention ,010309 optics ,Optics ,law ,0103 physical sciences ,Energy materials ,General Materials Science ,Physical and Theoretical Chemistry ,0210 nano-technology ,business - Abstract
The development of optical elements has seen tremendous advances over the last few decades for a variety of applications, including displays, cameras, and microscopes. Various optical elements have been developed, ranging from refractive elements to diffractive elements. In recent years, metasurfaces have been in the spotlight to develop next-generation optical elements beyond existing refractive or diffractive optics. A metasurface is a two-dimensional metamaterial composed of subwavelength artificial structures and has been studied for the development of optical elements with the major advantage that the properties of light can be freely adjusted by a thin flat structure. Optical lenses using metasurfaces can be hundreds of times thinner than conventional lenses, while at the same time, provide excellent focusing performance. This suggests that they can be applied to mobile and high-performance imaging applications in the future. Here, we discuss developments of optical elements from refractive or diffractive optics to metasurface optics, including basic principles and properties, current issues, and future perspectives.
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- 2020
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5. Metasurface for imaging and AR/VR devices
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Byoungho Lee, Changhyun Kim, Junhyeok Jang, Gun-Yeal Lee, and Jangwoon Sung
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- 2022
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6. Fourier ptychographic topography
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Hao Wang, Jiabei Zhu, Jangwoon Sung, Guorong Hu, Joseph Greene, Yunzhe Li, Seungbeom Park, Wookrae Kim, Myungjun Lee, Yusin Yang, and Lei Tian
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Atomic and Molecular Physics, and Optics - Abstract
Topography measurement is essential for surface characterization, semiconductor metrology, and inspection applications. To date, performing high-throughput and accurate topography remains challenging due to the trade-off between field-of-view (FOV) and spatial resolution. Here we demonstrate a novel topography technique based on the reflection-mode Fourier ptychographic microscopy, termed Fourier ptychograhpic topography (FPT). We show that FPT provides both a wide FOV and high resolution, and achieves nanoscale height reconstruction accuracy. Our FPT prototype is based on a custom-built computational microscope consisting of programmable brightfield and darkfield LED arrays. The topography reconstruction is performed by a sequential Gauss-Newton-based Fourier ptychographic phase retrieval algorithm augmented with total variation regularization. We achieve a synthetic numerical aperture (NA) of 0.84 and a diffraction-limited resolution of 750 nm, increasing the native objective NA (0.28) by 3×, across a 1.2 × 1.2 mm2 FOV. We experimentally demonstrate the FPT on a variety of reflective samples with different patterned structures. The reconstructed resolution is validated on both amplitude and phase resolution test features. The accuracy of the reconstructed surface profile is benchmarked against high-resolution optical profilometry measurements. In addition, we show that the FPT provides robust surface profile reconstructions even on complex patterns with fine features that cannot be reliably measured by the standard optical profilometer. The spatial and temporal noise of our FPT system is characterized to be 0.529 nm and 0.027 nm, respectively.
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- 2023
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7. Polarization-dependent asymmetric transmission using a bifacial metasurface
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Jongwoo Hong, Byoungho Lee, Gun-Yeal Lee, Jangwoon Sung, and Chulsoo Choi
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0303 health sciences ,Total internal reflection ,Computer science ,business.industry ,Holography ,Physics::Optics ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Polarization (waves) ,law.invention ,03 medical and health sciences ,Optics ,law ,Phase gradient ,General Materials Science ,Polarization dependent ,Photonics ,Scattered light ,0210 nano-technology ,business ,030304 developmental biology ,Nanopillar - Abstract
One of the most important research topic in optics and photonics is the design of metasurfaces to substitute conventional optical elements that demonstrate unprecedented merits in terms of performance and form factor. In this context, full-space control of metasurfaces that makes it possible to manipulate scattered light in transmission and reflection spaces simultaneously, is proposed as the next-generation scheme in optics, with a potential for applications such as 360° holographic images and novel optical systems. However, previously designed metasurfaces lacked functionality because the desired operation occurs under preconditioned light; therefore, they are difficult to use in real applications. Here, we present a design method that enables polarization-dependent full-space control, in which two independent and arbitrary phase profiles can be addressed to each space. Upon introducing a phase gradient value to realize the critical angle condition, conversion of transmissive into reflective operation is realized. Then, rectangular nanopillars are utilized to facilitate polarization beam splitting with the desired phase. Three samples were fabricated and measured based on the proposed scheme.
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- 2020
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8. Progresses in the practical metasurface for holography and lens
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Gun-Yeal Lee, Byoungho Lee, and Jangwoon Sung
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Physics ,business.industry ,QC1-999 ,Holography ,Metamaterial ,Physics::Optics ,02 engineering and technology ,021001 nanoscience & nanotechnology ,metamaterial ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,010309 optics ,Lens (optics) ,metasurface ,Optics ,law ,0103 physical sciences ,Electrical and Electronic Engineering ,0210 nano-technology ,business ,flat optics ,Biotechnology - Abstract
Metasurfaces have received enormous attention thanks to their unique ability to modulate electromagnetic properties of light in various frequency regimes. Recently, exploiting its fabrication ease and modulation strength, unprecedented and unique controlling of light that surpasses conventional optical devices has been suggested and studied a lot. Here, in this paper, we discuss some parts of this trend including holography, imaging application, dispersion control, and multiplexing, mostly operating for optical frequency regime. Finally, we will outlook the future of the devices with recent applications of these metasurfaces.
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- 2019
9. Recent advances in metasurface hologram technologies (Invited paper)
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Byoungho Lee, Jangwoon Sung, and Gun-Yeal Lee
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Materials science ,spatial light modulation ,General Computer Science ,meta‐hologram ,business.industry ,lcsh:Electronics ,Holography ,Nanophotonics ,Metasurface ,lcsh:TK7800-8360 ,Electronic, Optical and Magnetic Materials ,law.invention ,lcsh:Telecommunication ,Optics ,law ,lcsh:TK5101-6720 ,nanophotonics ,holography ,Electrical and Electronic Engineering ,business ,Spatial light modulation - Abstract
Since Leith and Upatnieks demonstrated the first optical hologram in 1964, hologram technology has attracted a great deal of interest in a wide range of optical fields owing to its potential use in future optical applications such as holographic imaging and optical data storage. Although there have been considerable efforts to develop holographic technologies using conventional optics, critical issues still hinder future development. Recently, metasurfaces composed of artificially fabricated subwavelength structures have been considered as novel holographic devices that show an unprecedented ability to control electromagnetic waves. In this review, we outline the recent progress in metasurface holography. A general introduction to several types of metasurface holography categorized based on their physics and application is provided. Then, our personal perspective on the future of this field is discussed.
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- 2019
10. Dynamic phase-change metafilm absorber for strong designer modulation of visible light
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Sun-Je Kim, Hansik Yun, Sungwook Choi, Jeong-Geun Yun, Kyungsoo Park, Sun Jae Jeong, Seung-Yeol Lee, Yohan Lee, Jangwoon Sung, Chulsoo Choi, Jongwoo Hong, Yong Wook Lee, and Byoungho Lee
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- 2021
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11. Absorptive metasurface color filters based on hyperbolic metamaterials for a CMOS image sensor
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Sang-Eun Mun, Byoungho Lee, Jangwoon Sung, Jongwoo Hong, Hyunwoo Son, and Changhyun Kim
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Materials science ,business.industry ,Image quality ,Physics::Optics ,Particle swarm optimization ,Metamaterial ,Extraordinary optical transmission ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,010309 optics ,Optics ,Reflection (mathematics) ,0103 physical sciences ,Color filter array ,Image sensor ,0210 nano-technology ,business ,Plasmon - Abstract
Metasurface color filters (MCFs) have attracted considerable attention thanks to their compactness and functionality as a candidate of an optical element in a miniaturized image sensor. However, conventional dielectric and plasmonic MCFs that have focused on color purity and efficiency cannot avoid reflection in principle, which degrades image quality by optical flare. Here, we introduce absorptive-type MCFs through truncated-cone hyperbolic metamaterial absorbers. By applying a particle swarm optimization method to design multiple parameters simultaneously, the proposed MCF is theoretically and numerically demonstrated in perceptive color on CIELAB and CIEDE2000 with suppressed-reflection. Then, a color filter array is numerically proven in 255 nm of sub-pixel pitch.
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- 2021
12. Dielectric metasurfaces for arbitrary engineering of multi-channel spin-orbit interactions
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Jangwoon Sung, Byoungho Lee, and Gun-Yeal Lee
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Physics ,Quantum optics ,business.industry ,Nanophotonics ,Optical communication ,Physics::Optics ,Dielectric ,Spin–orbit interaction ,Polarization (waves) ,Optics ,Orbit (dynamics) ,business ,Computer Science::Databases ,Spin-½ - Abstract
We experimentally demonstrate that dielectric metasurface can generate multi-channel vortex beams possessing different orbital angular momentums with arbitrarily engineered spin-orbit interactions. We propose a design principle of the proposed meta-atom that can modulate and switch spatial complex-amplitude information. Experimental results show that the proposed metasurface can generate multi-channel vortex beam arrays without interval noises, and it can make each vortex beam channel possess different spin-orbit conversion when the incident polarization is changed. These results provide a new opportunity to implement a novel vortex beam modulator, which can be applied for future development of quantum optics and optical communications.
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- 2020
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13. Full-space polarizing beam splitter via interleaved metasurface
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Jangwoon Sung, Gun-Yeal Lee, Chulsoo Choi, and Byoungho Lee
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Physics ,Birefringence ,business.industry ,Phase (waves) ,Physics::Optics ,Elliptical polarization ,Polarization (waves) ,Ray ,law.invention ,Optics ,Reflection (mathematics) ,law ,Miniaturization ,business ,Beam splitter - Abstract
Here, we present the metasurface design to split the incident light into transmission and reflection spaces according to its polarization states, and at the same time, the distinct phase profiles are imparted to each space. For implementation of this scheme, the linearly birefringent meta-atom is utilized for distinct phases at different polarization states. Interleaving methods is also utilized for switching the transmission-type into reflection-type. Three samples are fabricated for experimental demonstration of proposed scheme, each of them is operating in linear, circular, and elliptical polarization pair. We expect the miniaturization of conventional system might be achieved using this scheme.
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- 2020
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14. All-optical cryptography through metasurface based on phase changeable nanoantenna
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Byoungho Lee, Jangwoon Sung, Chulsoo Choi, and Sang-Eun Mun
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Materials science ,Chalcogenide ,business.industry ,Optical communication ,Phase (waves) ,Nanophotonics ,Encryption ,chemistry.chemical_compound ,chemistry ,Heat generation ,Optoelectronics ,Photonics ,business ,Ultrashort pulse - Abstract
Nanophotonic all-optical devices have been enthusiastically studied to overcome the speed bottleneck of electrical devices. Recently, chalcogenide phase change material Ge2Sb2Te5 (GST) based active metasurfaces have emerged as a novel platform as complement of all-optical device. GST has two phase, so called amorphous and crystalline phases that can be changed within nanosecond scale by applying external thermal stimuli. Hence, various ultrafast 2-level switchable GST based meta-devices have been proposed and demonstrated. However, since only two switching levels are provided, there are limitations in applying to various photonic fields. In this paper, we expand its switching functionality to three-level through designing two different sizes of GST nanorod that exhibits different heat generation density in case of top-hat shape light illumination. Thanks to this thermo-optical phenomenon, we can obtain partial phase changed state, so called intermediate state once the appropriate intensity of control light is illuminated. Harnessing intermediate state, we propose novel cryptography platform that can provide high security level encryption while providing ultrafast communication speed.
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- 2020
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15. Spiral Metalens for Phase Contrast Imaging
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Young-Jin Kim, Byoungho Lee, Junhyeok Jang, Jangwoon Sung, and Gun-Yeal Lee
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Biomaterials ,Optics ,Materials science ,business.industry ,Electrochemistry ,Phase-contrast imaging ,High resolution ,Condensed Matter Physics ,business ,Spiral ,Electronic, Optical and Magnetic Materials - Published
- 2021
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16. All-optical switching in reflection-type metasurface with Pancharatnam-Berry phase
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Taewon Choi, Jangwoon Sung, and Byoungho Lee
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Physics ,business.industry ,Holography ,Phase (waves) ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Optical switch ,law.invention ,010309 optics ,All optical ,Optics ,Geometric phase ,law ,0103 physical sciences ,Reflection (physics) ,0210 nano-technology ,business ,Circular polarization ,Photonic crystal - Abstract
We propose an optical switching metasurface in the designed visible region (680 nm) based on circularly polarized light using PB phase. It can generate holographic information encrypted by inserting control light.
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- 2020
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17. Ultracompact meta-pixels for high colour depth generation using a bi-layered hybrid metasurface
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Chulsoo Choi, Byoungho Lee, Jangwoon Sung, Hansik Yun, Jeong-Geun Yun, and Sun-Je Kim
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0301 basic medicine ,Amorphous silicon ,Materials science ,lcsh:Medicine ,02 engineering and technology ,Article ,Display device ,03 medical and health sciences ,chemistry.chemical_compound ,Optics ,Gamut ,Displays ,Position (vector) ,lcsh:Science ,Anisotropy ,Multidisciplinary ,Pixel ,business.industry ,lcsh:R ,Resonance ,021001 nanoscience & nanotechnology ,030104 developmental biology ,chemistry ,Metamaterials ,lcsh:Q ,Nanorod ,0210 nano-technology ,business - Abstract
Nano-structural colour pixels have attracted much attention as promising solutions for compact display devices. However, it is difficult to miniaturize and integrate conventional transmissive colour filtering components for high resolution pixels within subwavelength scale without sacrificing colour depth. Here, we propose a novel colour pixel structure using bi-layered hybrid metasurfaces that are composed of aluminum nanograting and amorphous silicon nanorod layers. The independent high-contrast control of resonance intensity and spectral position is achieved by anisotropic Mie resonances and cavity effect between stacked two metasurfaces. Moreover, the proposed structures permit the wide colour gamut through the novel physical principles. In addition, a meta-pixel which can provide gradual tuning of colour is demonstrated to obtain high colour depth. The proposed structures are expected to be fruitful for the development of next generation display and imaging systems.
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- 2019
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18. Wavelength-selective beam deflector based on Fano-resonant metasurface
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Jangwoon Sung, Sang-Eun Mun, Hyunwoo Son, and Byoungho Lee
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Physics ,business.industry ,Phase (waves) ,Physics::Optics ,Reflector (antenna) ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Optical switch ,Wavelength ,Optics ,Narrowband ,0103 physical sciences ,Physics::Accelerator Physics ,010306 general physics ,0210 nano-technology ,business ,Optical filter ,Phase modulation ,Beam (structure) - Abstract
We demonstrate the wavelength-selective beam deflector based on the Fano-resonant metasurface, which is composed of rotating double nanorods with metal film as reflector. By combining two concepts of phase modulation, geometric phase and Fano phase, we introduce the wavelength selective characteristics in optical beam switching. Our results can extend the studies for the application of metasurface that requires narrowband as well as broadband, such as optical switching and filtering.
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- 2019
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19. Independent Multichannel Wavefront Modulation for Angle Multiplexed Meta‐Holograms
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Byoungho Lee, Jangwoon Sung, Gun-Yeal Lee, and Junhyeok Jang
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Wavefront ,Optics ,Materials science ,business.industry ,Modulation ,law ,Holography ,business ,Multiplexing ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Spatial multiplexing ,law.invention - Published
- 2021
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20. Hybrid State Engineering of Phase‐Change Metasurface for All‐Optical Cryptography
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Sang-Eun Mun, Seung-Yeol Lee, Byoungho Lee, Chulsoo Choi, Jangwoon Sung, and Kyunghee Choi
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Materials science ,business.industry ,Holography ,Cryptography ,Condensed Matter Physics ,Phase-change material ,Engineering physics ,Electronic, Optical and Magnetic Materials ,law.invention ,Biomaterials ,All optical ,Phase change ,law ,Electrochemistry ,State (computer science) ,business - Published
- 2020
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21. Transmission-Type Color Filters with Silicon Mie Resonators using Guided-Mode-Resonance
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Jangwoon Sung, Byoungho Lee, Jongwoo Hong, and Young-Jin Kim
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Resonator ,Materials science ,Transmission (telecommunications) ,Silicon ,chemistry ,business.industry ,Guided-mode resonance ,Optoelectronics ,chemistry.chemical_element ,Color filter array ,business - Published
- 2019
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22. Metasurface Holograms and Metalenses for AR/VR
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Jangwoon Sung, Gun-Yeal Lee, and Byoungho Lee
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Physics ,Optics ,Geometric phase ,law ,business.industry ,Holography ,Holographic display ,Augmented reality ,Viewing angle ,business ,Phase control ,Electron-beam lithography ,law.invention - Abstract
We present recent advances on metasurface-originated applications. Two metasurfaces for full complex-amplitude hologram and full-space phase control and in particular, metalens for augmented reality with wide viewing angle are discussed.
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- 2019
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23. Thickness and temperature dependency of variation of dielectric functions of phase-change VO2 film
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Sungwook Choi, Byoungho Lee, Sun-Je Kim, Jangwoon Sung, and Yong Wook Lee
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Materials science ,Physics::Optics ,02 engineering and technology ,Dielectric ,Optical refraction ,021001 nanoscience & nanotechnology ,01 natural sciences ,Temperature measurement ,010309 optics ,Metal ,Condensed Matter::Materials Science ,Phase change ,Ellipsometry ,visual_art ,0103 physical sciences ,visual_art.visual_art_medium ,Condensed Matter::Strongly Correlated Electrons ,Composite material ,0210 nano-technology ,Deposition (law) - Abstract
In this paper, temperature- and thickness-dependent variation of dielectric functions of VO 2 film deposited by pulsed-laser deposition is characterized at both insulating and metallic phases by ellipsometry.
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- 2018
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24. Designed conversion of spin and orbital angular momentum
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Gun-Yeal Lee, Byoungho Lee, and Jangwoon Sung
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Physics ,Angular momentum ,Optical communication ,Physics::Optics ,Optical polarization ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Polarization (waves) ,01 natural sciences ,0104 chemical sciences ,Computational physics ,Optical imaging ,0210 nano-technology ,Quantum - Abstract
A novel metasurface providing arbitrarily designed spin-orbit interactions of light has been proposed. Our theoretical and experimental demonstrations show the great potential of the phenomenon for various applications including optical communications and quantum optical process.
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- 2018
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25. Independent phase modulation of two polarization states with reflection-type metasurface
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Chulsoo Choi, Gun-Yeal Lee, Jangwoon Sung, and Byoungho Lee
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Physics ,business.industry ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Polarization (waves) ,01 natural sciences ,Finite element method ,Optics ,Geometric phase ,0103 physical sciences ,010306 general physics ,0210 nano-technology ,business ,Dielectric waveguides ,Phase control ,Phase modulation - Abstract
Taking the advantage of propagation phase with geometric phase, we designed a novel reflection-type metasurface enabling independent phase control of two polarization states. This method achieves phase control with the high efficiency up to 95%.
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- 2018
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26. Complex-amplitude modulation of linear polarization via metasurface
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Chulsoo Choi, Jangwoon Sung, Gun-Yeal Lee, and Byoungho Lee
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Physics ,business.industry ,Linear polarization ,Holography ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Polarization (waves) ,01 natural sciences ,Finite element method ,law.invention ,Optics ,Amplitude ,law ,0103 physical sciences ,010306 general physics ,0210 nano-technology ,business ,Phase modulation ,Circular polarization ,Complex amplitude - Abstract
We present a novel complex amplitude modulation method for linear polarization from incident circular polarization. We achieved high efficiency up to 98 % with fulfilling continuous and independent modulation of amplitude and phase.
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- 2018
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27. Independent Phase Modulation of Transmitted and Reflected Light via Alignment-Free Bilayer Metasurface
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Jangwoon Sung, Gun-Yeal Lee, Chulsoo Choi, and Byoungho Lee
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Wavelength ,Materials science ,Optics ,business.industry ,Bilayer ,Metamaterial ,business ,Phase modulation ,Phase control ,Circular polarization - Abstract
We present a bilayer metasurface which has alignment-free characteristics. By adjusting the structural parameters, independent phase control is achieved in transmitted and reflected cross-polarized circular polarized light. In addition, the proposed metasurface shows high efficiency up to 50 % at the wavelength of 1550 nm by using all-dielectric materials as building blocks of the device.
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- 2017
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28. Light Path Switching Through Metasurface Based on V-Shape Ge2Sb2Te5 Antenna
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Jangwoon Sung, Chulsoo Choi, Yohan Lee, and Byoungho Lee
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Wavelength ,Phase change ,Optics ,Materials science ,business.industry ,Path switching ,Phase (waves) ,Physics::Optics ,Antenna (radio) ,business ,Circular polarization ,Amorphous solid ,Deflection angle - Abstract
We propose a novel method for active switching of optical deflection angle via the phase change of Ge2Sb2Tes (GST) metasurface. The 1650nm wavelength light deflects to the opposite directions according to amorphous or crystalline phase of GST in case of normal incidence with circular polarization.
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- 2017
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29. Refractive index sensor using layered nanoslit array based on Fabry-Pérot resonances
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Jangwoon Sung, Jongwoo Hong, Yohan Lee, Byoungho Lee, and Joonsoo Kim
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0301 basic medicine ,Materials science ,Field (physics) ,business.industry ,Resonance ,Reflector (antenna) ,Ranging ,01 natural sciences ,010309 optics ,03 medical and health sciences ,Wavelength ,030104 developmental biology ,Optics ,0103 physical sciences ,Optoelectronics ,business ,Refractive index ,Sensitivity (electronics) ,Fabry–Pérot interferometer - Abstract
We proposed a refractive index sensor using a phase-compensated cavity whose resonant wavelength can be tuned by the alignment between layers. The structures are composed of double-layered nanoslit array, which has total thickness of 100 nm while the cavity length is 30 nm thick. Using nanoslit array as a reflector has made it possible to design the phase shift carefully so that the subwavelength Fabry-Perot cavity can be obtained. When the cavity is filled with sensing medium, where the field enhancement is achieved by Fabry-Perot (FP) resonance, the proposed structure is found to achieve sensitivity ranging from 337 nm/RIU to 1250 nm/RIU at each different alignment. The resonant wavelength ranges from 1100 nm to 2500 nm, which contains biological windows and telecommunication wavelength range, so the structure is expected to be used in various purposes.
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- 2017
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30. Metasurface with Nanostructured Ge 2 Sb 2 Te 5 as a Platform for Broadband‐Operating Wavefront Switch
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Sang-Eun Mun, Hansik Yun, Chi-Young Hwang, Seung-Yeol Lee, Jangwoon Sung, Hee-Ok Kim, Chulsoo Choi, Jong-Heon Yang, Byoungho Lee, and Gun-Yeal Lee
- Subjects
Wavefront ,Optics ,Materials science ,law ,business.industry ,Beam steering ,Broadband ,Holography ,business ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention - Published
- 2019
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31. Single‐Layer Bifacial Metasurface: Full‐Space Visible Light Control
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Chulsoo Choi, Gun-Yeal Lee, Jangwoon Sung, Jongwoo Hong, and Byoungho Lee
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Materials science ,business.industry ,Beam steering ,Holography ,Metamaterial ,Space (mathematics) ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,Optics ,law ,business ,Single layer ,Visible spectrum - Published
- 2019
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32. Broadband ultrathin circular polarizer at visible and near-infraredwavelengths using a non-resonant characteristic in helically stackednano-gratings
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Byoungho Lee, Kyookeun Lee, Yohan Lee, Joonsoo Kim, Hansik Yun, Sun-Je Kim, Jeong-Geun Yun, and Jangwoon Sung
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Materials science ,Extinction ratio ,business.industry ,Physics::Optics ,02 engineering and technology ,Polarizer ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,law.invention ,010309 optics ,Wavelength ,Optics ,law ,0103 physical sciences ,Miniaturization ,Optoelectronics ,0210 nano-technology ,business ,Spectroscopy ,Anisotropy ,Circular polarization ,Visible spectrum - Abstract
Modern imaging and spectroscopy systems require to implement diverse functionalities with thin thickness and wide wavelength ranges. In order to meet this demand, polarization-resolved imaging has been widely investigated with integrated circular polarizers. However, the circular polarizers which operate at the entire visible wavelengths and have a thickness of several tens of nanometers have not been developed yet. Here, a circular polarizer, operating at the entire visible wavelength range, is demonstrated using helically stacked aluminum nano-grating layers. High extinction ratio and broad operation bandwidth are simultaneously achieved by using non-resonant anisotropic characteristics of the nano-grating. It is theoretically verified that the averaged extinction ratio becomes up to 8 over the entire visible wavelength range while having a thickness of 390 nm. Also, the feasibility of the proposed structure and circular polarization selectivity at the visible wavelength range are experimentally verified. It is expected that the proposed structure will lead to extreme miniaturization of a circular polarizer and contribute greatly to the development of mobile/wearable imaging systems such as virtual reality and augmented reality displays. (C) 2017 Optical Society of America
- Published
- 2017
33. Broadband metasurface for chiral phase control
- Author
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Jangwoon Sung, Byoungho Lee, and Gun-Yeal Lee
- Subjects
Physics ,business.industry ,0103 physical sciences ,Broadband ,Optoelectronics ,Chiral phase ,02 engineering and technology ,021001 nanoscience & nanotechnology ,010306 general physics ,0210 nano-technology ,business ,01 natural sciences - Published
- 2017
- Full Text
- View/download PDF
34. Active directional switching of surface plasmon polaritons using a phase transition material
- Author
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Sun Jae Jeong, Sang-Eun Mun, Hansik Yun, Yong Wook Lee, Joonsoo Kim, Kyookeun Lee, Jongwoo Hong, Kyungsoo Park, Jangwoon Sung, Byoungho Lee, Jeong-Geun Yun, and Sun-Je Kim
- Subjects
Permittivity ,Phase transition ,Multidisciplinary ,Materials science ,business.industry ,Surface plasmon ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Optical switch ,Surface plasmon polariton ,Article ,010309 optics ,0103 physical sciences ,Optoelectronics ,Photonics ,0210 nano-technology ,business ,Plasmon ,Localized surface plasmon - Abstract
Active switching of near-field directivity, which is an essential functionality for compact integrated photonics and small optoelectronic elements, has been challenging due to small modulation depth and complicated fabrication methods for devices including active optical materials. Here, we theoretically and experimentally realize a nanoscale active directional switching of surface plasmon polaritons (SPPs) using a phase transition material for the first time. The SPP switching device with noticeable distinction is demonstrated based on the phase transition of vanadium dioxide (VO2) at the telecom wavelength. As the insulator-to-metal phase transition (IMT) of VO2 induces the large change of VO2 permittivity at telecom wavelengths, the plasmonic response of a nanoantenna made of VO2 can be largely tuned by external thermal stimuli. The VO2-insulator-metal (VIM) nanoantenna and its periodic array, the VIM metagrating, are suggested as optical switches. The directional power distinction ratio is designed to change from 8.13:1 to 1:10.56 by the IMT and it is experimentally verified that the ratio changes from 3.725:1 to 1:3.132 as the VIM metagratings are heated up to 90 °C. With an electro-thermally controllable configuration and an optimized resonant design, we expect potential applications of the active switching mechanism for integrable active plasmonic elements and reconfigurable imaging.
- Published
- 2016
35. Broadband efficient modulation of light transmission with high contrast using reconfigurable VO2 diffraction grating
- Author
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Sungwook Choi, Jinsoo Jeong, Sang-Eun Mun, Hansik Yun, Jangwoon Sung, Yong Wook Lee, Sun-Je Kim, Byoungho Lee, Yohan Lee, and Chulsoo Choi
- Subjects
Diffraction ,Materials science ,business.industry ,Physics::Optics ,02 engineering and technology ,Grating ,021001 nanoscience & nanotechnology ,01 natural sciences ,Directivity ,Atomic and Molecular Physics, and Optics ,010309 optics ,Amplitude modulation ,Optics ,Transmission (telecommunications) ,Modulation ,0103 physical sciences ,Broadband ,0210 nano-technology ,business ,Diffraction grating - Abstract
Ultra-compact dynamically reconfigurable modulation of optical transmission has been widely studied by using subwavelength-spaced resonant metasurface structures containing reconfigurable optical materials. However, it has been difficult to achieve high transmissivity, large modulation depth, and broad bandwidth simultaneously with the conventional resonance-based metasurface schemes. Here, we propose a reconfigurable phase-transition diffractive grating, made of thick VO2 ridge waveguides, for achieving the above-mentioned three goals simultaneously in the near-infrared range. Based on the large dielectric-to-plasmonic transition characteristic of VO2 in the near-infrared range, diffraction directivity of dual-VO2 ridge waveguide is designed to be tuned by thermally driven phase transition of VO2 for transverse electrically polarized illumination. Then, the diffractive VO2 ridge waveguide grating composed of the periodically arranged dual VO2 ridge waveguides is designed with on-state efficiency around 0.3 and minimum modulation depth about 0.35 over a broad bandwidth of 550 nm (1100-1650 nm). The working principle and excellent modulation performance are thoroughly verified through numerical and experimental studies.
- Published
- 2018
- Full Text
- View/download PDF
36. Simultaneous control of polarization and amplitude over broad bandwidth using multi-layered anisotropic metasurfaces
- Author
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Jangwoon Sung, Byoungho Lee, Sun-Je Kim, and Jeong-Geun Yun
- Subjects
Materials science ,business.industry ,Broad bandwidth ,Physics::Optics ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Polarization (waves) ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Amplitude modulation ,Optics ,Amplitude ,0103 physical sciences ,Broadband ,Phase compensation ,Optical rotation ,010306 general physics ,0210 nano-technology ,Anisotropy ,business - Abstract
In this paper, the broadband transmissive modulation of polarization and amplitude is demonstrated with high efficiency and tunability using multi-layered aluminum metasurfaces. Broadband and nondispersive optical rotation in the optical frequency region is realized by using Fabry-Pérot-like cavity and phase compensation. Simultaneously, the transmission amplitude can be independently controlled by adjusting the twist angle of the anisotropic metasurfaces. The proposed polarization-amplitude modulators are numerically demonstrated to achieve large tunability with an amplitude modulation depth of 0.95 and maximum rotation angle of 180°.
- Published
- 2018
- Full Text
- View/download PDF
37. Ultracompact Broadband Plasmonic Polarimeter
- Author
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Gun-Yeal Lee, Kyookeun Lee, Byoungho Lee, Sang-Eun Mun, Hansik Yun, and Jangwoon Sung
- Subjects
Physics ,business.industry ,Polarimeter ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Polarization (waves) ,01 natural sciences ,Surface plasmon polariton ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,010309 optics ,0103 physical sciences ,Broadband ,Optoelectronics ,0210 nano-technology ,business ,Plasmon - Published
- 2018
- Full Text
- View/download PDF
38. Deflection angle switching with a metasurface based on phase-change nanorods [Invited]
- Author
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Seung-Yeol Lee, Jangwoon Sung, Chulsoo Choi, Jeong-Geun Yun, Sun-Je Kim, and Byoungho Lee
- Subjects
Materials science ,business.industry ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Deflection angle ,Amorphous solid ,010309 optics ,Phase change ,Wavelength ,Optics ,Phase (matter) ,0103 physical sciences ,Nanorod ,Electrical and Electronic Engineering ,0210 nano-technology ,business ,Anisotropy ,Circular polarization - Abstract
We propose the active metasurface using phase-change material Ge2Sb2Te5 (GST), which has two distinct phases so called amorphous and crystalline phases, for an ultrathin light path switching device. By arranging multiple anisotropic GST nanorods, the gradient metasurface, which has opposite directions of phase gradients at the two distinct phases of GST, is demonstrated theoretically and numerically. As a result, in the case of normal incidence of circularly polarized light at the wavelength of 1650 nm, the cross-polarized light deflects to −55.6° at the amorphous phase and +55.6° at the crystalline phase with the signal-to-noise ratio above 10 dB.
- Published
- 2018
- Full Text
- View/download PDF
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