Past Forward: The Nobelist’s First Laser

When George Porter arrived at the University of Cambridge in 1945 as a Ph.D. student, he found the equipment remarkably primitive. Students had to build their own oscilloscopes! To conduct his research—detecting the short-lived molecules known as free radicals—Porter pieced together a setup that included a surplus army searchlight powered by a surplus diesel engine. After seeing flash lamps at a Siemens factory, he decided to modify his approach, replacing the continuous light source with short, intense pulses of light. With his flash photolysis technique, Porter was able to capture reactions lasting mere milliseconds. To study even faster reactions, though, he needed a faster light source, for which he’d have to wait. The ruby laser, invented in 1960, was the ideal solution. Porter used this one to record nanosecond-scale reactions. Flash photolysis is still used to study semiconductors, nanoparticles, and photosynthesis, among other things. For their work on high-speed, lightdriven chemical reactions, Porter; his Ph.D. adviser, Ronald G.W. Norrish; and Manfred Eigen shared the 1967 Nobel Prize in Chemistry.