A5070892078- Atmospheric chemistry and aerosols
- Atmospheric aerosols and clouds
- Advanced Fluorescence Microscopy Techniques
- Cold Atom Physics and Bose-Einstein Condensates
- Atmospheric Ozone and Climate
- Photoacoustic and Ultrasonic Imaging
- Quantum Information and Cryptography
- Optical Coherence Tomography Applications
- Air Quality and Health Impacts
- Quantum optics and atomic interactions
- Advanced Frequency and Time Standards
- Digital Holography and Microscopy
- Spectroscopy Techniques in Biomedical and Chemical Research
- Atmospheric and Environmental Gas Dynamics
- Advanced Optical Sensing Technologies
- Random lasers and scattering media
- Aeolian processes and effects
- Mechanical and Optical Resonators
- Vehicle emissions and performance
- Medical Malpractice and Liability Issues
- Integrated Circuits and Semiconductor Failure Analysis
- Photonic and Optical Devices
- Near-Field Optical Microscopy
- Orbital Angular Momentum in Optics
- Dispute Resolution and Class Actions
Korea University
2015-2025
Institute for Basic Science
2019-2023
Pusan National University
2022-2023
Seoul National University
2008-2018
University of Bonn
2012-2015
Samsung (South Korea)
2008
Catholic University of Korea
2006
University of California, Berkeley
2006
University of Illinois Urbana-Champaign
1999
The study uses satellite observations, global assimilated aerosol data sets, Atmospheric Brown Clouds (ABC) observatories, a Monte Carlo aerosol‐cloud‐radiation model and regional chemical transport (STEM‐2K) to characterize the spatial extent of brown clouds, megacity ABC hot spots, composition direct radiative forcing. It presents first annual cycle observations forcing from observatories in Indo‐Asia‐Pacific regions. East Asia, Indo‐Gangetic Plains, Indonesian region, southern Africa...
Abstract. We present initial validation results of the space-borne lidar CALIOP onboard CALIPSO satellite using coincidental observations from a ground-based in Seoul National University (SNU), Seoul, Korea (37.46° N, 126.95° E). analyze six selected cases between September 2006 and February 2007, including 3 daytime night-time covering different types clear cloudy atmospheric conditions. Apparent scattering ratios calculated two measurements total attenuated backscatter at 532 nm show...
Abstract. Transport of aerosols in pollution plumes from the mainland Asian continent was observed situ at Jeju, South Korea during Cheju Brown Cloud Plume-Asian Monsoon Experiment (CAPMEX) field campaign throughout August and September 2008 using a 3-laser photoacoustic spectrometer (PASS-3), chemical filter analysis, size distributions. The PASS-3 directly measures effects morphology (e.g. coatings) on light absorption that traditional filter-based instruments are unable to address. mixed...
Abstract. PM1.0, PM2.5, and PM10 were sampled at Gosan ABC Superstation on Jeju Island from August 2007 to September 2008. The carbonaceous aerosols quantified with the thermal/optical reflectance (TOR) method, which produced five organic carbon (OC) fractions, OC1, OC2, OC3, OC4, pyrolyzed (OP), three elemental (EC) EC1, EC2, EC3. mean mass concentrations of 13.7 μg m−3, 17.2 28.4 respectively. averaged fractions OC EC 23.0% 10.4% for 22.9% 9.8% 16.4% 6.0% PM10. Among sub-components, OC2...
We report on the observation of cooperative radiation exactly two neutral atoms strongly coupled to single mode field an optical cavity, which is close lossless-cavity limit. Monitoring cavity output power, we observe constructive and destructive interference collective Rayleigh scattering for certain relative distances between atoms. Because backaction onto atoms, power two-atom case ($N=2$) almost equal single-emitter ($N=1$), in contrast free-space where one would expect $N^2$ scaling...
Myelination processes are closely related to higher brain functions such as learning and memory. While their longitudinal observation has been crucial understanding myelin-related physiology various disorders, skull opening or thinning required secure clear optical access. Here we present a high-speed reflection matrix microscope using light source with wavelength of 1.3 μm reduce tissue scattering aberration. Furthermore, develop computational conjugate adaptive optics algorithm designed...
Multiple light scattering hampers imaging objects in complex media. Approaches used real practices mainly aim to filter out multiple obscuring the ballistic waves that travel straight through medium. Here, we propose a method makes deterministic use of for microscopic an object embedded deep within The proposed finds stack phase plates generate similar trajectories as original By implementing inverse using identified plates, our rectifies and amplifies by almost 600 times. This leads...
Abstract. The Mass Absorption Cross section (MAC) and Ångström Exponent (AAE) have been commonly estimated for ambient aerosols but rarely black carbon (BC) or organic aerosol (OA) alone in the conditions. Here, we provide estimates of BC (and OA) MAC AAE East Asian outflow, by analyzing field data collected at Gosan ABC super site. At this site, EC OC) mass, absorption coefficient 7 wavelengths PM mass density were continuously measured from October 2009 to June 2010. We remove with...
Abstract A mouse skull is a barrier for high-resolution optical imaging because its thick and inhomogeneous internal structures induce complex aberrations varying drastically from position to position. Invasive procedures creating either thinned-skull or open-skull windows are often required the microscopic of brain tissues underneath. Here, we propose label-free modality termed laser scanning reflection-matrix microscopy recording amplitude phase maps reflected waves at non-confocal points...
Abstract Over the past decade, reflection matrix microscopy (RMM) and advanced image reconstruction algorithms have emerged to address fundamental imaging depth limitations of optical in thick biological tissues complex media. In this study, we introduce significant advancements processing algorithms, including logical indexing, power iterations, low-frequency blocking. These enhance speed aperture synthesis, 3D reconstruction, aberration correction by orders magnitude. Detailed algorithm...
Anthropogenic aerosols were measured together with CO at Gosan (33°17′N, 126°10′E) on Jeju Island, South Korea, between 17 March and 5 April 2005. Outflow of these from the Asian continent was associated a high‐pressure system centered over northern region China Mongolia. Air masses are classified into five distinct categories basis origin: marine, free troposphere, Yellow Sea, China. The concentrations show large variations because alternation air masses, while wet scavenging another...
Abstract. The ability of seven state-of-the-art chemistry–aerosol models to reproduce distributions tropospheric ozone and its precursors, as well aerosols over eastern Asia in summer 2008, is evaluated. study focuses on the performance used assess impacts pollutants climate air quality part EU ECLIPSE project. Models, run using same emissions, are compared different spatial scales situ surface, vertical profiles satellite data. Several rather clear biases found between model results...
Abstract Label-free in vivo imaging is crucial for elucidating the underlying mechanisms of many important biological systems their most native states. However, applicability existing modalities has been limited to either superficial layers or early developmental stages due tissue turbidity. Here, we report a synchronous angular scanning microscope rapid interferometric recording time-gated reflection matrix, which unique matrix characterizing full light-specimen interaction. By applying...
Abstract. Aerosol size distribution, total concentration (i.e. condensation nuclei (CN) concentration, NCN), cloud (CCN) (NCCN), hygroscopicity at ~90% relative humidity (RH) were measured a background monitoring site Gosan, Jeju Island, south of the Korean Peninsula in August 2006, April to May 2007 and October 2008. Similar measurements took place 2009 another (Baengnyeongdo Comprehensive Monitoring Observatory, BCMO) on island Baengnyeongdo, off west coast Peninsula. Both islands found be...
Abstract A recently developed new particle formation (NPF)‐explicit version of the Weather Research and Forecasting Chemistry (WRF‐chem) model can explicitly calculate growth sink nucleated clusters with 20 aerosol size bins from 1 nm to 10 µm in diameter. In this study, was used investigate spatial temporal variations NPF event frequency concentrations aerosols (condensation nuclei, CN) cloud condensation nuclei (CCN) within boundary layer East Asia spring 2009. We found a distinct...
We experimentally demonstrate real-time feedback control of the joint spin-state two neutral cesium atoms inside a high finesse optical cavity. The quantum states are discriminated by their different cavity transmission levels. A Bayesian update formalism is used to estimate state occupation probabilities as well transition rates. stabilize balanced two-atom mixed state, which deterministically inaccessible, via and find very good agreement with Monte Carlo simulations. On average, loop...
Abstract. Total number concentrations of particles having a diameter larger than 10 nm (NCN), cloud condensation nuclei at several supersaturation (S) values (NCCN) and size distributions with 10–414 were measured in Seoul between 2004 2010. Overall average NCN geometric mean 17 811 ± 5581 cm−3 48 6 nm. Average NCCN 0.4, 0.6 0.8% S 4145 2016, 5323 2453 6067 2780 corresponding / 0.26 0.11, 0.33 0.11 0.37 0.12. There is clear seasonal variation aerosol concentration, which seems to be due the...
Abstract. Aerosol, rainwater, and sea fog water samples were collected during the cruise conducted over subarctic western North Pacific Ocean in summer of 2008, order to estimate dry, wet, deposition fluxes atmospheric inorganic nitrogen (N). During events, mean number densities particles with diameters larger than 0.5 μm decreased by 12–78%, suggesting that could act preferentially as condensation nuclei (CN) for droplets. Mean concentrations nitrate (NO3−), methanesulfonic acid (MSA), non...