He worked at Harvard Medical School from 2003 to 2004 and at Applied Physics Department at CALTECH from 2004 to 2005 as a postdoctoral scholar. Since 2005, he has worked as a professor in the Department of Chemistry at POSTECH and an adjunct professor in the School of Interdisciplinary Bioscience and Bioengineering and Division of Environmental Science and Engineering at POSTECH. He has published over 100 peer-reviewed journal articles in the area of nanophotonics, nanoplasmonics, and nanobiotechnology, and is an inventor of dozens of patents. His work has been cited over 10,000 times so far.