Dr. K. K. Choi is currently a senior technical consultant to government, industry, and academia. He had been the Senior Research Scientist (ST) for physical sciences at the US Army Research Laboratory for the last 17 years. In this capacity, he planned and coordinated Army-wide physical science research to advance state-of-the-art defense capabilities. He invented the quantum well infrared photodetector and the resonator-pixel technology that have pivotal impacts on military, space, and scientific applications worldwide. He participated in the design and production of QWIP sensors on board of NASA Landsat-8 and Landsat-9 satellites for Earth’s resource and climate observation. His resonator-pixel technology improved the performance of the state-of-the-art short-wave infrared detectors and achieved program goals.