Nobel Laureate Donna Strickland calls her work a ‘laser hammer’, a breakthrough that delivers energy in powerful bursts. In an interview with TNIE’s Tamreen Sultana, she unpacks the science, its real-world impact and the journey from lab failures to global recognition.
If you had to explain your research to someone without a science background, how would you describe it?
I usually explain it by saying I built a “laser hammer.” Some applications don’t just need energy — they need that energy delivered very quickly and in a concentrated way. It’s like trying to push a nail into a piece of wood. You can push as hard as you want, but it won’t go in. The moment you use a hammer, it works because the energy is delivered in a sharp, sudden burst.
In optics, the same idea applies. What matters is energy density — how much energy is packed into a very small space and time. Light comes in the form of photons, and we already know how to focus it in space using lenses. But there’s also a third dimension, which is time — how long the pulse lasts.
What we did was stretch the laser pulse to reduce its intensity, safely amplify it, and then compress it back down again. That way, we could create a very intense, controlled burst of energy — essentially mimicking the effect of a hammer, but using light.
Why is this research important?
The importance of this work really became clear through its applications. Lasers could cut materials like steel because the light gets absorbed and converted into heat — much like how you feel the warmth of the sun on your skin. When you focus that energy into a small spot, it becomes intense enough to cut through metal.
But materials like glass behave differently — light passes through them instead of being absorbed. That meant traditional laser cutting methods didn’t work.
With this technique, we can now deposit energy inside transparent materials. In a way, we can “hammer” energy into a precise point within the material without affecting the surface. This has made it possible to do things like cutting or modifying structures inside glass, and even performing delicate medical procedures such as shaping the cornea during eye surgery. So the impact goes far beyond physics — it extends into medicine and manufacturing.
Was the limitation in the laser itself or something else?
The limitation wasn’t really the laser — it was the pulse. Laser amplifiers are capable of producing a large amount of energy, but the challenge is how that energy is delivered.
If you try to send a very short pulse through the system, the energy becomes extremely concentrated and can damage the equipment — almost like hitting it with a hammer before it’s ready. On the other hand, if you use a longer pulse, you can safely deliver the energy, but you lose that sharp intensity that makes it useful for certain applications.
So the real problem was finding a way to combine both — to safely amplify the energy while still being able to deliver it in a very short, powerful burst. That balance is what our work achieved.
How did you get into this field and begin your research?
I was always strong in maths and physics, so I felt quite early on that I belonged in that space. When choosing my undergraduate programme, I picked engineering physics because it included lasers, which sounded interesting and a bit different.
The undergraduate school I chose had an engineering physics programme, and one part of it focused on lasers. I thought that sounded cool, and that’s how I got into the field. A graduate student there suggested that I consider going to Rochester, which is one of the major optics schools.
Later, when I arrived at the University of Rochester, a fellow Canadian noticed me during my first week. I told him I wanted to study lasers, and the next day he took me to the laser lab and introduced me to Gérard Mourou. He gave me a paper to read on high-order nonlinear optics, which at that time was purely theoretical. He suggested that if I could think of a way to apply it using one of the lab’s lasers, I could turn it into a thesis.
I came up with a scheme that I thought would work, but it didn’t. However, while working on that, I got involved in another part of the problem — figuring out how to generate very intense laser pulses. That part turned out to be successful, and it eventually became the foundation of my research.
Your work was published decades before the Nobel Prize. Why did recognition take so long?
That kind of timeline is actually quite common in science. Some discoveries are recognised quickly because they have immediate experimental confirmation, like gravitational waves or the Higgs boson. These were things people were waiting for, and when they were finally observed, it was a big moment.
In other cases, work done earlier doesn’t immediately stand out as a major breakthrough. For example, some work from the 1970s was not initially considered as significant, and recognition came much later.
In our case, the work didn’t have one dramatic breakthrough moment. Instead, its importance became clear gradually, as more and more applications emerged over time. It kept being reconsidered year after year, until eventually it was recognised for the impact it had made across different fields.
What challenges did you face during your PhD?
Like most research, it involved a lot of failure. Experiments didn’t work, equipment broke, and results didn’t match expectations. But that’s simply part of the process. You learn from each setback and keep moving forward. Research is often about persistence — continuing despite things not working, until eventually something does.
Are ultrafast lasers used in warfare today?
I don’t think ultrafast lasers are used in warfare, at least not in any practical way that I’m aware of. Even when we first developed the technology, there was speculation. Some people joked that while we claimed to be working on atomic physics, the real goal was to blow up missiles.
To address that, we demonstrated the actual scale of the technology. We showed that we had to focus the laser down to about 100 microns just to remove a tiny piece of material. These are not high average power lasers — they are high peak power lasers.
That means they can do very precise things on a microscopic scale, but they are not suited for large-scale destruction. So I don’t think they are used in warfare. And if they are, I wouldn’t know — I’m not involved in anything classified.
What are you currently working on?
I still spend most of my time building laser systems, which is something I’ve always enjoyed. I continue to explore new wavelength ranges such as the mid-infrared and ultraviolet using multi-frequency and Raman-based techniques. My work also extends into medical applications, particularly in using high-power lasers to precisely modify the microcrystalline lens of the human eye. At the moment, I’m also working on nonlinear optics using two different colours of light, which allows us to explore new ways of manipulating laser behaviour.
One project involves generating longer wavelengths in the mid-infrared range, while another focuses on creating even shorter pulses by combining frequencies. I’m also part of a collaborative project exploring laser accelerators for medical use. The idea is to potentially deliver radiation through fibre optics, allowing surgeons to precisely target and eliminate remaining tumour cells during procedures. It’s still in the early stages, but it’s an exciting direction.
Alongside my research, I’ve taken on leadership roles within the optics community through Optica, where I’ve served as president and now chair its Presidential Advisory Committee. I also contribute to broader scientific networks, including the Canadian Association of Physicists and the University of Waterloo’s TRuST research initiative
Has the approach to experimentation changed over the years?
In terms of tools and technology, it has changed a lot. When I started, we were using Polaroid cameras, paper outputs, and manually operating equipment. Today, everything is computer-controlled, and we’re moving toward more automated and possibly AI-assisted systems.
However, the core nature of experimentation hasn’t really changed. It still involves trial and error, testing ideas, dealing with failures, and gradually refining the approach. The tools are more advanced, but the process itself remains quite similar.
Do you use AI in your research?
I don’t personally use AI directly in my work, but I have seen it being applied to analyse experimental data. In some cases, machine learning can help identify patterns or simplify analysis that would otherwise be quite complex.
Going forward, I think it will become increasingly useful, especially as experiments generate larger and more detailed datasets.
What did winning the Nobel Prize feel like?
It was incredibly exciting. I remember it was early in the morning, around 5 am on October 2, and I was holding onto my husband and thinking, “I think I’m getting the Nobel Prize.”
That day was overwhelming — I received around 1,500 emails, got a call from the Prime Minister, and was interviewed all over the place. It was a completely different experience.
Since then, I’ve had opportunities that most scientists don’t usually get. I’ve had an audience with the Pope, met rock stars, and even met Apollo astronauts.
I met them at an event called Starmus. It’s organised with the involvement of Brian May from Queen, who is also an astrophysicist. After winning the Nobel Prize, I was invited to speak there. At that time, several Apollo astronauts attended. I ended up meeting Charlie Duke in a very unexpected way — my husband and I sat down next to his wife at lunch without realising who she was. When he joined us, we had a conversation, and only afterwards did it really sink in that we had just shared a meal with someone who had walked on the Moon.
Did it impact your work?
Yes, it definitely changed things. I’ve taken on more public speaking and outreach, which I felt was important given the platform I was given. At the same time, it has meant spending less time on day-to-day research and with my students.
So while it’s been rewarding, it has also shifted how I balance my responsibilities.
As one of the few women Nobel laureates in physics, did you face unique challenges?
It was largely the same until I won the Nobel Prize. After that, things shifted slightly because, for a long time, there were only three women who had ever won the prize in physics — and often, only one of them was alive at a time. Each of us, in a way, carried that visibility alone.
For a couple of years, I found myself in that position, being the only living woman Nobel laureate in physics, which came with a certain sense of responsibility. Then, when another woman won, I reached out to her and joked that I was starting a “female physics Nobel laureate club” and asked if she’d like to join.
Now, I’ve gone from being the third to one of three living laureates, and it feels much easier. There’s a sense of shared presence now — we can share that space and the attention that comes with it. But overall, I didn’t really feel held back in my career because of it.
Was there a defining moment in your career?
Getting the opportunity to work on that PhD project was definitely a turning point. It gave me a strong start and opened up opportunities that shaped my career.
At the same time, there were many failures along the way. Research rarely goes smoothly, but that initial opportunity allowed me to keep going and eventually find something that worked.
What advice would you give to aspiring physicists?
I wouldn’t advise anyone to aim for a Nobel Prize or any major award. That’s not something you can control, and focusing on it can be discouraging. It’s a lot of luck winning a prize like that. Instead, you should focus on setting goals that are achievable and meaningful to you.
More importantly, try to find something you genuinely enjoy doing, so that you can go to work every day and actually enjoy it. If you’re not enjoying the work, it becomes very difficult to do it well. So the key is to figure out what you want to do and build a career around that.