Harry Albert Atwater, Jr.[1] is an American physicist and materials scientist and is the Otis Booth Leadership Chair of the division of engineering and applied science at the California Institute of Technology.

Currently he is the Howard Hughes Professor of Applied Physics and Materials Science and the director for the Liquid Sunlight Alliance (LiSA), a Department of Energy Hub program for solar fuels.

His current research in energy centers on high efficiency photovoltaics, carbon capture and removal, and photoelectrochemical processes for generation of solar fuels.

From 2014 to 2020, Atwater served as director of the Joint Center for Artificial Photosynthesis (JCAP), the DOE Energy Innovation Hub for solar fuels.

He is also founder of 5 early-stage companies, including Captura, which is developing scalable approaches to carbon dioxide removal from oceanwater, and Alta Devices, which set world records for photovoltaic cell and module efficiency.

Recently, his research has expanded to include the study of artificial photosynthesis to design fully-integrated photoelectrochemical (PEC) device for the production of renewable fuels.