Winfried Denk (born 12 November 1957) is a German physicist, director of the Max Planck Institute of Neurobiology in Martinsried, close to Munich. He is noted for being the first to implement two-photon microscopy while a postdoctoral fellow in Watt W. Webb's lab at Cornell University in 1990. Denk later (1994) recognized that two-photon microscopy has unique properties for imaging live cells deep in highly scattering tissues. His second major invention is a machine that automatically acquires three-dimensional images at a resolution of a few nanometers. This technique, known as Serial Block-Face Scanning Electron Microscopy (SBFSEM or SBEM), has been commercialized by the company Gatan.He received Grete Lundbeck European Brain Research Prize in 2015.