Ki‐Hun Jeong

This work presents the fabrication of biologically inspired artificial compound eyes. The artificial ommatidium, like that of an insect's compound eyes, consists of a refractive polymer microlens, a light-guiding polymer cone, and a self-aligned waveguide to collect light with a small angular acceptance. The ommatidia are omnidirectionally arranged along a hemispherical polymer dome such that they provide a wide field of view similar to that of a natural compound eye. The spherical configuration

The enhancement of surface enhanced Raman scattering (SERS) with nanogap-rich silver nanoislands surrounding glass nanopillars at wafer level is reported. High-density hot spots are generated by increasing the number of nanogap-rich nanoislands within a detection volume. The SERS substrate shows a high enhancement factor of over 10(7) with excellent signal uniformity (∼7.8%) and it enables the label-free detection of aqueous DNA base molecules at nanomolar level.

UNLABELLED: Frontotemporal dementia (FTD) is a common cause of presenile dementia. The aim of the current study was 2-fold: (a) to delineate the brain regions with reduction of glucose metabolism, and (b) to investigate the hemispheric asymmetry of glucose metabolism in FTD using (18)F-FDG PET. METHODS: We compared the regional metabolic patterns on (18)F-FDG PET images obtained from 29 patients with FTD and 11 healthy subjects using a voxel-wise analysis (statistical parametric mapping [SPM]).

We report a tunable microdoublet lens capable of creating dual modes of biconvex or meniscus lens. The microdoublet lens consists of a tunable liquid-filled lens and a solid negative lens. It can be tuned either by changing the shape of the liquid-filled lens into bi-convex or meniscus or by changing a filling media with different refractive index. The micro-fabrication is based on photopolymer microdispensing and elastomer micromolding methods. The microdoublet lens can provide a solution for m

Bridging the gap between ultrashort pulsed optical waves and terahertz (THz) waves, the THz photoconductive antenna (PCA) is a major constituent for the emission or detection of THz waves by diverse optical and electrical methods. However, THz PCA still lacks employment of advanced breakthrough technologies for high-power THz emission. Here, we report the enhancement of THz emission power by incorporating optical nanoantennas with a THz photoconductive antenna. The confinement and concentration

Biomarkers in tear fluid have attracted much interest in daily healthcare sensing and monitoring. Recently, surface-enhanced Raman scattering (SERS) has enabled highly sensitive label-free detection of small molecules. However, a highly stable straightforward tear assay with superior sensitivity is still under development in tear collection and analysis. Here we report a plasmonic Schirmer strip for on-demand, rapid, and simple identification of biomarkers in human tears. The diagnostic strip fe

The quantitative label-free detection of neurotransmitters provides critical clues in understanding neurological functions or disorders. However, the identification of neurotransmitters remains challenging for surface-enhanced Raman spectroscopy (SERS) due to the presence of noise. Here, we report spread spectrum SERS (ss-SERS) detection for the rapid quantification of neurotransmitters at the attomolar level by encoding excited light and decoding SERS signals with peak autocorrelation and near-

Advent and fast spread of pandemic diseases draw worldwide attention to rapid, prompt, and accurate molecular diagnostics with technical development of ultrafast polymerase chain reaction (PCR). Microfluidic on-chip PCR platforms provide highly efficient and small-volume bioassay for point-of-care diagnostic applications. Here we report ultrafast, real-time, and on-chip nanoplasmonic PCR for rapid and quantitative molecular diagnostics at point-of-care level. The plasmofluidic PCR chip comprises

Many animal species employ highly conspicuous traits as courtship signals for successful mating. Fireflies utilize their bioluminescent light as visual courtship signals. In addition to efficient bioluminescent light emission, the structural components of the firefly lantern also contribute to the enhancement of conspicuous optical signaling. Recently, these firefly lantern ultrastructures have attracted much interest and inspired highly efficient light management approaches. Here we report on t

Emerging molecular diagnosis requires ultrafast polymerase chain reaction (PCR) on chip for rapid precise detection of infectious diseases in the point-of-care test. Here, we report nanoplasmonic on-chip PCR for rapid precision molecular diagnostics. The nanoplasmonic pillar arrays (NPA) comprise gold nanoislands on the top and sidewall of large-scale glass nanopillar arrays. The nanoplasmonic pillars enhance light absorption of a white light-emitting diode (LED) over the whole visible range due

This work reports a novel method for monolithic fabrication of high numerical aperture polymer microlens arrays (high-NA MLAs) with high packing density (PD) at wafer level. The close-packed high-NA MLAs were fabricated by incorporating conformal deposition of ultrathin fluorocarbon nanofilm and melting the cylindrical polymer islands. The NA and PD of hemispherical MLAs with a hexagonal arrangement increase up to 0.6 and 89%, respectively. The increase of NA enhances the lens transmission secur