By Sharon McFarlane
Senior Communications Officer, Advancement
At the June 2025 Convocation, the Faculty of Science will award an honorary degree to Dr. Paul Corkum, one of Canada’s most distinguished physicists and a pioneer of attosecond science. In an engaging conversation with the University, Dr. Corkum reflected on his scientific journey, what keeps him curious, and what young scientists should carry with them as they graduate. Below are excerpts from our Q&A with the “father of attosecond science.”
Q: You’re often referred to as the “father of attosecond science.” For those outside the field, can you explain what that is and why it matters?
A: Since the invention of the laser, we’ve been trying to make shorter and shorter pulses of light. The shorter the pulse, the faster the event we can observe. But by the 1990s, we hit a wall. You couldn’t get much shorter than a single cycle of light.
That’s when I started thinking differently. I figured out a way to generate attosecond pulses -these are flashes of light that last a billionth of a billionth of a second. With them, we can study electrons, which are the fastest-moving parts of atoms and molecules. It opened a new frontier in understanding chemistry, physics, and even electronics.
Imagine pulling seaweed off a rock with a wave. In this analogy, a light wave takes the place of the ocean wave, an electron takes the place of the seaweed and the ion is the rock. When a wave comes, the seaweed floats up from the rock and then, as the wave passes, it crashes back into the rock from which it just left. At the ocean one can actually hear the crash. In the analogy where an electron crashes, the crash gives off light – the attosecond pulse -- not sound. This light flash is the fastest process that we, as humans, can control in nature. It's simple and beautiful. The control all comes from controlling waves.
Q: What first set you on the path to becoming a physicist?
A: Honestly, I wasn’t good at many things, but I was good at solving physics problems. That made the decision pretty easy. I went to Acadia University, a small place where I got into a lab early on. I published my first paper as an undergrad, in Nature, which was a big moment for me.
From there, I thought I’d be a theorist, but I got a job in experimental physics by telling my future boss I could take apart a car and put it back together. That worked! Over time, I gained the skills and ideas that led me into lasers, short pulses, and eventually attosecond science.
Q: You’ve mentored countless students over your career. What do you admire most in young scientists?
A: Good ideas. I recently asked my graduate students to read papers and come up with their own new ideas in response. I think a good scientist has a bunch of ideas bouncing around in their head all the time, and every so often, they pick a good one. You don’t always know which will succeed, but the ability to think creatively and independently is key.
Q: Donna Strickland, a former postdoc of yours, says she learned science by talking it through with others. How important is that kind of collaboration in your work?
A: She’s absolutely right. Science is very social. People often think of scientists as isolated figures working alone, but that’s not how it works. Most scientific papers have multiple authors. I always say, “You’ve never heard of a novel written by five people, but you’ve rarely seen a scientific paper written by just one.”
Even though many of us are introverts, science forces you to be outgoing. You meet people around the world, discuss ideas constantly, give talks, and yes, sell your work. Nothing gets supported if you keep it to yourself. You have to share it so others can build on it.
Q: Why do you think Canadian scientists have had such a big influence on the global stage?
A: That's a good question. I don’t think there’s one answer. Sometimes talent just clusters in unexpected places. But I will say that Canada gives scientists a lot of freedom to follow their ideas, and that matters. There's not always a top-down direction. If you have a good idea and can convince others it's worth pursuing, you can do great work.
Q: Where do you think science is headed in the next few decades?
A: That’s hard to say. If we knew where the next big breakthroughs were, we’d already be working on them! But I do think pushing the boundaries of speed—how fast we can see and control things—is still a frontier. The Nobel Prizes can be a good guide; they often signal where the most promising areas of discovery are.
Q: After such a long and successful career, what keeps your curiosity alive?
A: I think about science all the time. I daydream about problems I want to solve. Right now, I’m fascinated by whether we can flip the spin of an electron using just a simple laser, something that usually requires massive, billion-dollar machines. That kind of question keeps me going.
If you find a problem interesting enough, it just won’t let you go. That’s how you know you’re in the right field.
Q: Do you have a message for this year’s graduating science students?
A: I guess I’d say this: the life you’ll have in science is probably different from what you imagine now. But it might be better. You’ll meet people from around the world, see events through their eyes, and be part of a global conversation. It’s not a solitary life. It’s a life filled with discovery, ideas, and community. And if you find something you truly love thinking about, it will never get old.
Congratulations to Dr. Paul Corkum on receiving an Honorary Degree from the University of Waterloo. And congratulations to the Class of 2025. May your curiosity lead you to surprising and wonderful places.