Donna Strickland discusses education, research and current projects

This magazine style interview was conducted in the spring of 2022 by Defining Moments Canada Contributing Historian Denisa Popa. The interview was separated into 3 thematic sections: The Nobel Prize, Scientific Education and Scientific Research.

Donna Strickland is a canadian phycisist, professor at the University of Waterloo, and Nobel Laureate in physics from Guelph, Ontario. She earned a PhD in optics from the University of Rochester and a Bachelor of Engineering from McMaster University. Since earning her PhD in 1989, she has worked at Princeton University and the University of Waterloo.

Denisa Popa is a PhD student at the Institute for the History and Philosophy of Science and Technology (IHPST) at the University of Toronto. Her doctoral research focuses on Canadian medical history. She holds an MA from the IHPST and a Hon. BSc in Molecular Genetics and Microbiology, also from the University of Toronto. Denisa is part of the Defining Moments Canada team as a Contributing Historian for the Herzberg50 and NobelCanadian projects.

Photo courtesy of UWaterloo

The Nobel Prize 

Denisa Popa (DP)In October, it will be four years since your Nobel Prize was announced. How has your life changed in these last five years? What has been the most memorable part?

Donna Strickland (DS) -My life has changed a lot in some respects, and not at all in others. I get a lot of invitations to speak—more than I can possibly accept. I travel a lot more than I ever have. I have had incredible experiences where I’ve met rock stars, astronauts, and other noteworthy people doing really important work. It’s still amazing to me that I was at an event with people who have walked on the moon. At the Nobel banquet, I had a king on my left and a prince on my right. But I still have a lab where I conduct my research, and I still teach and supervise graduate students. I’m glad it hasn’t all changed.

DPWhen you reflect on becoming a Nobel Laureate, how do you explain it to yourself? In your opinion, what does your Nobel Prize mean to Canadian Science?

DS -It still kind of surprises me. Over the years colleagues asked if I thought CPA (Chirped-Pulse Amplification) would win a Nobel Prize, but I never thought I would win. One of the most surreal moments of my life was when I signed the register at the Nobel Foundation. Before they have you sign, they show you signatures in the book.  For me they started with Albert Einstein and then Marie Curie. Not all names in the register are as famous as those first names I was shown, but I simply couldn’t believe that I was signing the same book as those legendary scientists. The Nobel Prize brings global recognition to the value of science and when a Canadian wins, it is validation that the work done by our scientists is exceptional and has made a change to society in some significant way. All Canadians can take pride in the accomplishment because together as a society we support the science done in the country.  I know I am always very proud when I hear that a fellow Canadian has won a Nobel Prize.

DP -How has your platform changed since winning the Nobel Prize? Do people seek out your opinion more? 

DS -Oh yes, it has changed a lot. I am asked to sit on boards of directors of companies as well as scientific institutions.  I have participated in panel discussions at conferences on everything from ocean research, to travelling to Mars, to science policy.  Sitting on these panels has allowed me to interact with exceptional people, which is why I accept the challenge, but I always make it clear to the host that I am an expert only in high-intensity laser physics.

DP -Is the Nobel Prize the award you are most proud of, or the most important to you, or is that another prize?

DS-Yes. It’s the epitome when it comes to science. I was also particularly thrilled to be named a companion of the Order of Canada in 2019.

DP -This interview is part of a larger project entitled NobelCanadian, which aims to commemorate and teach students about the Nobel Prizes won by Canadian laureates. In your opinion, what would you want students to know about the Nobel Prize?

DS -The Nobel Prize was the first global prizefor science. Alfred Nobel insisted that the prize be given to the scientist who had made the largest contribution to help mankind in the previous year.  These two considerations have made this prize the ultimate prize in science and why Canadians pay attention when a Canadian wins a Nobel Prize.  

DP- Of the many Canadian researchers throughout history who have studied and contributed to scientific innovation, who do you think was also deserving of the Nobel Prize?

DS -Paul Corkum is a scientist at the National Research Council where I worked with him as his second post-doctoral fellow.  He is now also a professor of physics at the University of Ottawa. Actually, getting to work with him was a goal of mine. Being his postdoctoral fellow was the only job I wanted after finishing my PhD, and I was lucky enough to get it. Even back then, he was considered Canada’s leading expert in ultrafast optics. Later he worked on the development of attosecond science. The attosecond timescale is short enough to measure the motion of electrons in atoms and molecules. They help us make movies of atomic motion.

Photo courtesy of UWaterloo

Science Education

DP -What was your own educational experience like with STEM subjects growing up? Do you feel your science education gave you the tools to pursue your incredible career? If there is something you could tell your middle-school or high-school self now with regards to your journey with science education, what would it be?

DS -I really liked physics and chemistry. I did not enjoy dissecting a frog or a fish, so was very sure that I was not aiming for medicine as a career.  I think I was also fortunate that a math teacher in high school had a connection with the math department at the University of Waterloo and so we were able to start studying computer science at high school even back in the ‘70s. My homeroom teacher in high school was also my grade 13 physics teacher.  I felt I knew him fairly well by the time he was teaching me physics and I guess he knew me well enough to keep pushing me to do better.  He thought I was a bit of a slacker, which I could be at times. I also had a wonderful chemistry teacher.  She was always showing us cool experiments with equipment she could borrow from the University of Guelph.  I definitely got the quality education I needed to do well at university. 

Life has worked out well for me, and I always went through life thinking it would work out, so I don’t have anything to say to my younger self. 

DP- In your autobiography on the Nobel website, you speak about growing up and attending primary and secondary school during the 1970s– can you speak more about that and how that era and your surroundings influenced your schooling and scientific career in Canada?

DS -That was the era of women’s liberation and Helen Reddy singing  “I am woman, hear me roar.”  I believed that a woman could do anything she wanted and I didn’t let anyone else tell me different.  I also had a mother who told me to be whatever I wanted to be.  I went to a high school where no one made a big deal about girls doing well in math and science.  At my high school graduation, the three math prizes went to girls.  I won the grade 11 prize in physics.  One of my girlfriends won the grade 13 physics prize. I was always good at math and science in school, and I was also really shy.  I remember dreading having to go up to the front at school to get my physics prize.  I thought people would think I was a nerd. But they were nice and I recall they congratulated me and said it must be nice to be so smart. Both of my parents were very supportive. They loved science. Our family vacations were learning opportunities. My mother thinks it was my father who showed me first laser. We were at the Ontario Science Centre and they had one. As my mom tells it, my dad called me over to see it because he thought it was the way of the future.

DP- What do you think is a key aspect of science education that may be overlooked?

DS –Science is about discovery, which means scientists are always asking questions about how everything works, from the entire universe down to the smallest particles and every complex thing in between. When we teach science from elementary school through undergraduate courses at university, we teach the students the science that has already been discovered and ask them to learn about that science.  We test them on what they know.  We do not ask them to question how everything works and we don’t test them on asking good questions. So, we don’t really prepare science students to become scientists until graduate school.  We should address the mystery of science and discuss more often what we do not know and get the students to think about what questions should be asked.

DP -How do you think we can encourage more young women to consider career paths in STEM? As a parent/teacher what do you think parents and teachers can do?

DS -I would like for students and their parents to know that this is the time for them to figure out what they enjoy and what they’re good at. Not everyone is cut out to be a scientist and that’s OK. But if it’s what you enjoy, you’ll do a good job at it.  If you really know yourself and feel science is where you belong, no one can take that away from you.  I remember a history teacher telling me that math and physics were subjects for boys.  I simply thought she was wrong and that it was a silly thing to say to me.  I knew I was a girl who did very well at math and science, so to me they were obviously girls’ subjects too.  Parents and teachers need to encourage students to find out what subjects interest them the most and then encourage the exploration of that subject.

Photo Courtesy of UWaterloo

DP -Can you speak to the importance of mentorship for young scientists? Did you have a mentor during your undergraduate/graduate studies?

DS -Growing up, I did not think much about mentors.  I suppose my parents were my mentors.  They both encouraged me.  My father was an engineer and my mother was a teacher.

I was fortunate to study under amazing scientists.   In graduate school, Gérard Mourou was my mentor. He was my supervisor. I learned a lot from him and together we developed CPA, which ended up winning the Nobel Prize.  I then got to work with Paul Corkum who was also an amazing scientist, but he took quite a different approach to his research.  Gérard was always coming up with new ideas and getting his students to try them out.  Paul at the time only had one postdoc to help him in the lab, so he really worked through his ideas carefully from a number of different directions before he attempted them in the lab.

DP- Dr. Gerhard Herzberg, a German-Canadian physicist who won the Nobel Prize in Chemistry in 1971 often spoke about the importance of having an interdisciplinary education. He also spoke about how his early interdisciplinary education (in both the humanities and sciences) helped develop his skills in scientific writing and communication. What are your thoughts on an interdisciplinary education in both the sciences and humanities? Did you also have an interdisciplinary education?

DS -I do think it’s important to have a well-rounded education. Scientists need to communicate well. Perhaps more people would appreciate the importance of science if scientists were better at communicating not just their accomplishments, but also the major challenges we face as a society, like climate change.  I guess thinking back to one of your previous questions, I would tell my younger self to work harder on my English classes so I might enjoy writing more than I do.  Writing is very important part of the job of scientist.

DP- Another topic Herzberg spoke about was promoting scientific literacy in general audiences. In light of the ongoing COVID-19 pandemic, it seems that we are all learning more about microbiology and immunology. What are your views on scientific literacy and scientific communication and how can we go about making science more accessible to everyone and avoiding mis-information/misinterpretation of scientific research and concepts?

DS -Science literacy is something I hope to have some positive impact on.  I would like to see Canada have more programs to bring scientists and excellent communicators together.  The projects should be about combining science and music or science and art.  I saw a wonderful art exhibit about the beauty of math entitled Mathemalchemy, while it was on display at the National Academy of Sciences in the U.S. The point of combining science with the arts is to bring the beauty and wonder of science to people who don’t normally think about science.  I would also like to see universities have more programs about science literacy where we bring together the scientists, engineers and mathematicians with our colleagues across campus who study psychology, social science and communications.  We need to understand why our society still thinks it is ok to say “Oh math – that is too hard for me”  when they would probably never say “reading is too hard for me.”  We don’t need everyone to be scientists, just as we don’t need everyone to be authors, but we do need everyone to understand the scientific process along with concepts like probabilities.  With this understanding they can better understand the reason the public health community wants us to be vaccinated and what steps we must take to help our environment to remain habitable.  

Scientific Research 

DP -Reflecting on the discovery for which you were awarded the Nobel Prize – chirped pulse amplification– what drew you to this topic and is your work on this particular topic finished? Has your success with this discovery influenced the research topics you pursued afterwards?

DS -I went to McMaster University for my undergrad in Engineering Physics because part of that program was about lasers.  I just felt that studying lasers would be fun.  I don’t know why I thought lasers would be fun but of course we didn’t see them around in those days. They were in scientific labs mostly or in sci-fi movies.  My PhD supervisor, Gérard Mourou asked me if I would be interested in studying high order harmonic generation, which is a process that transforms the colour of the light out to the ultraviolet and beyond towards x-rays.  At the time, we had lasers that worked in the visible region, which means the colours we see with our eyes and we also lasers that worked in the infrared.  The question was how to get the same type of light, which we call coherent, and is what makes laser light travel in a tight beam and be very intense out towards the x-rays.  The project intrigued me I suppose simply because it had not been done before.  In order for our project to work, we needed a very intense laser beam and there was no laser that would work for the project.   That is why I was the student in Gérard’s group who  got to work on this project.  I was the only student in the group using short pulse lasers to increase the intensity.  The others were trying to make the pulses shorter to allow faster imaging of fast processes.

I still develop new types of short pulse laser amplifier.  Currently I am working on developing two colour short pulse fiber laser amplification where the pulses won’t have as a high peak power as the largest lasers in the world, but many more pulses per second are emitted allowing for more measurements to be made in a shorter time.

Photo courtesy of UWaterloo

DP -What projects are you working on now? Has the focus of your work shifted since you won the prize? Has your lab grown or changed in any way?

DS -I am still working on creating short intense pulses.  Now instead of going towards the x-ray my group works on getting further out in the infrared.  I have also started working on a project with Toshiki Tajima, the inventor of Laser Wakefield Acceleration.  Our two groups are collaborating to develop a fiber laser electron accelerator for medical applications to remove small tumors. 

I don’t get to work in my lab as often as I used to as I am travelling all the time, except for when I was working from my dining room and not permitted in the lab due to the pandemic.  I do have a slightly larger group now, but I don’t want too large of a group to manage.  I mostly now talk to my group using on-line meetings.

DP- In commemoration of Dr. Herzberg’s Nobel Prize one of the resources Defining Moments Canada put together was a short video explaining the basics of spectroscopy. In 1-2 paragraphs could you explain the foundational elements of your Nobel research to an audience who is learning about your story and scientific work?

DS -Light intensity is the power per unit area and the power is the energy divided by the time duration of the light pulse.  At the time, we had lasers that could generate high-energy pulses and we had lasers that could generate very short pulses.  When scientists tried amplifying the short pulses in the high energy amplifiers, they destroyed the laser rods.  Some scientists had to investigate what optical interaction was causing the damage, and the laser scientists simply stopped trying to directly amplify short pulses.  My supervisor, Gérard Mourou realized that we would have to find a way to stretch the short pulses before amplifying them and then compress the pulses back to being short after amplification.  Once we had this approach to short pulse laser amplification, known as chirped pulse amplification, we had a tool, which I like to call a laser hammer.  It was this laser hammer that was damaging the laser rods when scientists first tried amplifying short pulses. 

CPA enables the most intense laser pulses ever created. It allows for precise, clean cuts that are ideal for transparent materials, such as slicing the cornea as part of corrective eye surgery or machining small glass parts. Surgeons remove the patient’s lens during cataract surgery with a CPA laser. Scientists are using the most powerful CPA lasers to accelerate particles to one day reach deep-tissue tumours, such as inoperable brain cancer. It’s this exciting possibility that has countries around the world investing in the development of the highest-intensity lasers.

Courtesy of UWaterloo