Dr. Sohn is a physicist in the Advanced Electronics Group in the Nanoscale Device Characterization Division of the Physical Measurement Laboratory at the National Institute of Standards and Technology (NIST). He worked for the Electronics and Telecommunications Research Institute (ETRI) and Samsung Electronics Semiconductor Laboratory before joining NIST. He developed the NIST 193 nm Scatterfield Imaging Microscope, enabling sophisticated illuminations for nanostructure characterization. Using this unique tool, he is developing DUV microscopy techniques for 3-dimensional phase imaging and characterization of nanoscale dimensions. He is also leading the photonic quantum state imaging metrology project that will elucidate the fundamental quantum phenomena in single nanoparticle systems.