A couple of weeks after I photographed W. E. Moerner, a package arrived in the mail. Inside was his QSL card, the kind amateur radio operators exchange to confirm contact over the air. It was an unexpected continuation of a day we had spent talking about experiments and the pleasure of making things work.
I made his portrait in the summer of 2024, seated at his ham radio setup in the garage of his Los Altos home. Later, at Stanford, I picked my way through the stacks of papers and reports filling his office, looking for a place to stand with the camera. Years of thought had taken physical form around him. There were projects in those piles, questions pursued across decades, an extraordinary accumulation of a working mind. He sat surrounded by his life’s work.
Our conversation moved easily between molecular physics, the joy of discovery, and a life spent teaching, mentoring, and connecting with people. He delighted in the apparatus of science, in how an experiment was built and what it might reveal. I enjoyed his enthusiasm for the details.
Much of chemistry measures enormous numbers of molecules together. The results describe their average behavior, concealing differences among individuals. Moerner helped make it possible to observe one molecule at a time.
In 1989, at IBM, he and his colleague Lothar Kador detected the absorption of light by a single molecule embedded in a solid. Using a carefully tuned laser and extremely low temperatures, they isolated its response from the surrounding material. Here was a signal they could attribute to one molecule alone.
That achievement helped lay the foundation for a new kind of microscopy. An ordinary optical microscope renders a tiny light source as a blurred spot. When nearby molecules glow together, their spots overlap. But let only a few well-separated molecules shine at once, and their positions can be measured precisely. Repeat this with different molecules, then assemble their locations, and a detailed image emerges.
In 1997, Moerner’s laboratory showed that individual molecules of a variant of green fluorescent protein could be switched between bright and dark states using light. This ability to control which molecules were visible became an important part of the story. In 2014, he shared the Nobel Prize in Chemistry with Eric Betzig and Stefan Hell for the development of super-resolution fluorescence microscopy.
These methods let researchers examine the organization of cells and follow individual molecules as they move. Structures once lost in a blur become distinguishable. Behavior hidden in an average can be studied directly, revealing differences that matter to how living cells work.
The papers surrounding him represented years of such work, but our conversation never felt like a retrospective. He was interested in the experiments themselves and in what might be tried next. At his radio setup in the garage, that technical curiosity had another outlet, along with the pleasure of reaching someone far away.
His QSL card brought me back to that garage and the man at the radio, listening for someone on the other end. I had come to make his portrait and left with a friend. The card seemed a fitting acknowledgment: contact made. We have stayed in touch.
