A5030965127- Adaptive optics and wavefront sensing
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Photonic and Optical Devices
- Optical Coherence Tomography Applications
- Atmospheric chemistry and aerosols
- Advanced Optical Sensing Technologies
- Spectroscopy and Laser Applications
- Galaxies: Formation, Evolution, Phenomena
- Air Quality and Health Impacts
- Advanced Fiber Laser Technologies
- Vehicle emissions and performance
- Photonic Crystals and Applications
- Spectroscopy Techniques in Biomedical and Chemical Research
- Astronomical Observations and Instrumentation
- Optical Network Technologies
- Photonic Crystal and Fiber Optics
- Advanced Fiber Optic Sensors
- Astrophysics and Star Formation Studies
- Analytical Chemistry and Sensors
- Optical Wireless Communication Technologies
- Advanced Fluorescence Microscopy Techniques
- Infrastructure Resilience and Vulnerability Analysis
- Risk and Safety Analysis
- Reliability and Maintenance Optimization
University of California, Los Angeles
2022-2024
National Disaster Management Research Institute
2017-2024
Astrobiology Center
2023
National Institutes of Natural Sciences
2023
National Astronomical Observatory of Japan
2023
Seoul National University
2005-2021
Konkuk University Medical Center
2016
Konkuk University
2008-2016
Kangwon National University
2016
National Institute of Environmental Research
2016
Abstract Photonic lanterns (PLs) are tapered waveguides that gradually transition from a multimode fiber geometry to bundle of single-mode fibers (SMFs). They can efficiently couple telescope light into entrance at the focal plane and convert it multiple beams. Thus, each SMF samples its unique mode (lantern principal mode) in pupil, analogous subapertures aperture masking interferometry (AMI). Coherent imaging with PLs be enabled by interference outputs applying phase modulation, which...
Abstract Episodic wintertime particle pollution by ammonium nitrate is an important air quality concern across the Midwest U.S. Understanding and accurately forecasting PM 2.5 episodes are complicated multiple pathways for aerosol formation, each with uncertain rate parameters. Here, Community Multiscale Air Quality model (CMAQ) simulated regional atmospheric budgets during 2009 LADCO Winter Nitrate Study, using integrated process (IPR) reaction (IRR) tools to quantify relevant processes....
Adaptive optics (AO) systems are critical in any application where highly resolved imaging or beam control must be performed through a dynamic medium. Such applications include astronomy and free-space optical communications, light propagates the atmosphere, as well medical microscopy vision science, biological tissues. Recent works have demonstrated common-path wavefront sensors (WFSs) for adaptive using photonic lantern (PL), slowly varying waveguide that can efficiently couple multi-moded...
Abstract Coronagraphs allow for faint off-axis exoplanets to be observed, but are limited angular separations greater than a few beam widths. Accessing closer-in would greatly increase the expected number of detectable planets, which scales inversely with inner working angle. The vortex fiber nuller (VFN) is an instrument concept designed characterize within single width. It requires optical elements and compatible many coronagraph designs as complementary characterization tool. However,...
There is an ongoing debate on whether feedback from active galactic nuclei (AGNs) can effectively regulate the star formation activities in their host galaxies. To investigate effect of AGN-driven outflows, we perform integral-field spectroscopic observations 40 moderate-luminosity (10$^{41.5}$ $<$ L$_{\rm [OIII];cor}$ 10$^{43.1}$ erg s$^{-1}$) Type-2 AGNs at z 0.1, which present strong outflow signatures integrated [OIII] kinematics. Based radial profile normalized velocity dispersion by...
Abstract The direct imaging of an Earth-like exoplanet will require sub-nanometric wave-front control across large light-collecting apertures to reject host starlight and detect the faint planetary signal. Current adaptive optics systems, which use sensors that reimage telescope pupil, face two challenges prevent this level control: non-common-path aberrations, caused by differences between sensing science arms instrument; petaling modes: discontinuous phase aberrations pupil fragmentation,...
We present numerical characterizations of the wavefront sensing performance for few-mode photonic lantern sensors (PLWFSs). These include calculations throughput, control space, sensor linearity, and an estimate maximum linear reconstruction range standard hybrid lanterns with between 3 19 ports, at λ =1550nm. additionally consider impact beam-shaping optics a charge-1 vortex mask placed in pupil plane. The former is motivated by application PLs to high-resolution spectroscopy, which could...
Photonic lantern nulling (PLN) is a method for enabling the detection and characterization of close-in exoplanets by exploiting symmetries ports mode-selective photonic (MSPL) to cancel out starlight. A six-port MSPL provides four where on-axis starlight suppressed, while off-axis planet light coupled with efficiencies that vary as function planet's spatial position. We characterize properties in laboratory perform first testbed demonstration PLN monochromatic (1569 nm) broadband (1450 1625...
We investigate the potential of photonic lantern (PL) fiber-fed spectrometers for two-dimensional spectroastrometry. Spectroastrometry, a technique studying small angular scales by measuring centroid shifts as function wavelength, is typically conducted using long-slit spectrographs. However, slit-based spectroastrometry requires observations with multiple position angles to measure spectroastrometric signals. In typical configuration PL-fed spectrometers, light from focal plane coupled into...
Surface brightness fluctuation (SBF) magnitudes are a powerful standard candle to measure distances semi-resolved galaxies in the local universe, majority of which dwarf that have often bluer colors than bright early-type galaxies. We present an empirical $i-$band SBF calibration blue regime, $0.2 \lesssim (g-i)_0 0.8$ Hyper Suprime-Cam (HSC) magnitude system. for 12 nearby various morphological types with archival HSC imaging data, and use their tip red giant branch (TRGB) derive - color...
한반도를 포함하는 동아시아 지역에 영향을 미치거나 피해를 발생시킬 수 있는 화산으로는 일본 화산과 백두산을 포함하여중국의 동부지역에 위치한 개의 활화산은 물론 거리는 3,000km 정도 떨어져 있으나 한반도 주변의 항공 운항에 결정적인 영향을미칠 활화산이 러시아의 캄차카반도에도 다수 분포되어 있다. 이에 본 연구에서는 2005년~2013년 기간의 기상 자료를 기반으로 주요 화산의 가상 분화 시나리오에 의해 수행된 화산재 확산 해석 결과를 이용하여 화산재의 영향 가능성을 확률적으로 분석하였다. 그 결과 백두산과 아소산의 경우 화산폭발지수 7로 분화하는 경우, 7월에서 9월에 전역에 미칠 가능성이 가장 클 것으로 분석되었으며, 울릉도도 유사한 기간에 영향의 상대적으로 높을 분석되었다, 이는 여름철에 나타나는 지역 압력 배치 때문으로 파악되었다.
Abstract An independent determination of H 0 is crucial given the growing tension between Hubble constant, , derived locally and that determined from modeling cosmic microwave background (CMB) originating in early universe. In this work, we present a new using velocities tip red giant branch (TRGB) distances to 33 galaxies located Local Group Virgo cluster. We use model infall pattern local flow modified by mass, which as function cosmological constants ( Ω Λ ), radius zero-velocity surface...
Coronagraphs allow for faint off-axis exoplanets to be observed, but are limited angular separations greater than a few beam widths. Accessing closer-in would greatly increase the expected number of detectable planets, which scales inversely with inner working angle. The Photonic Lantern Nuller (PLN) is an instrument concept designed characterize within single beam-width, using device called Mode-Selective (MSPL), photonic mode-converter that maps linearly polarized modes into individual...
New frontiers of astronomical science push the imaging capabilities modern AO-equipped telescopes. However, precision measurement at diffraction limit is made challenging by time-varying residual aberrations in AO-corrected wavefronts. Photonic lanterns (PLs) are a novel technology whose spatial filtering and coherence properties may be exploited to enable new limit. We aim determine potential AO-fed PL fiber spectrometers for spectroastrometry. define spectroastrometric signals 6-port...
In order to improve air quality in the Seoul Metropolitan Area (SMA), "Special Act on Air Quality Improvement" has been enforced since 2005.The strategy resulted some reduction of pollution, but there not much research into quantitative impact analysis each separate preventive countermeasure.Therefore, we analyzed nitrogen oxide resulting from implementation emission control plan for on-road mobile sources.The MM5-SMOKE-CMAQ model system was employed prediction.Reduced NOx emissions SMA...
Abstract M64 is a nearby spiral galaxy with Type III antitruncation component. To trace the origin of component, we present Hubble Space Telescope/Advanced Camera for Surveys (ACS) F606W/F814W photometry resolved stars in field located outer disk ( <?CDATA $2\buildrel{\,\prime}\over{.} 5\lesssim r\lesssim 6\buildrel{\,\prime}\over{.} 5$?> ) M64. At $r\approx 5\buildrel{\,\prime}\over{.} (7 kpc) to east, discover new metal-poor globular cluster ${R}_{\mathrm{eff}}=5.73\pm 0.02$?> pc and M V =...
Photonic Lanterns (PLs) are tapered waveguides that gradually transition from a multi-mode fiber geometry to bundle of single-mode fibers (SMFs). They can efficiently couple telescope light into entrance at the focal plane and convert it multiple beams. Thus, each SMF samples its unique mode (lantern principal mode) in pupil, analogous subapertures aperture masking interferometry (AMI). Coherent imaging with PLs be enabled by interfering outputs applying phase modulation, which achieved...
Photonic lantern nulling (PLN) is a method for enabling the detection and characterization of close-in exoplanets by exploiting symmetries ports mode-selective photonic (MSPL) to cancel out starlight. A six-port MSPL provides four where on-axis starlight suppressed, while off-axis planet light coupled with efficiencies that vary as function planet's spatial position. We characterize properties in laboratory perform first testbed demonstration PLN monochromatic (1569 nm) broadband (1450 nm...
<title>Abstract</title> In the event of a major volcanic eruption in Korean Peninsula and other neighboring countries, there is potential for widespread damage due to ash fallout, affecting various sectors across country. Our study focuses on analyzing importance interconnectedness different areas develop effective risk assessment techniques mitigation measures. We classified susceptible analyzed risks interconnections each sector using analytic network process (ANP). categorized caused by...