Lena Fitting Kourkoutis (June 6, 1979 – June 24, 2023) was an American physicist working in the field of electron microscopy, and a professor of applied and engineering physics at Cornell University.Her research focused on the use of aberration-corrected scanning transmission electron microscope,providing atomic resolution, at cryogenic temperatures (>77K) to study physical processes such as superconductivity and biological structures such as proteins.