Inside every human cell, thousands of proteins work as molecular machines to make life possible. Even the largest of these proteins are far too small to see with ordinary light; so instead scientists take pictures of proteins using beams of electrons. These electron microscopes take pictures sharp enough to see the individual atoms that make up proteins.

However, traditional electron microscopes struggle to produce high contrast images since proteins only interact weakly with passing electrons. To solve this problem, scientists at UC Berkeley have developed the world’s most powerful continuous laser and installed it in a state-of-the-art electron microscope. The new microscope takes some of the clearest images to date of tiny proteins like haemoglobin, which carries oxygen in the blood and is essential for human life.

Eric Cooper is a postdoctoral scholar in Prof. Holger Muller’s group at the University of California, Berkeley. He received his PhD in experimental atomic physics from Stanford in 2024. He now uses tools from atomic physics, including lasers and high-quality mirrors, to control electrons and build state-of-the-art electron microscopes.

Artist rendering of the laser phase plate electron microscope. (Credit: SayoStudio, produced for publicity about our project)
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