Donna Strickland: Girls just wanna have fun — in the lab

At the BiOS Plenary Session on Sunday, 2019 SPIE President Jim Oschmann welcomed Canadian optical physicist Donna Strickland of University of Waterloo to the stage.

Less than two months earlier, in December 2018, Strickland had been led to the podium to speak at the Nobel Prize Award Ceremony in Stockholm, Sweden, and accept the Nobel Prize in Physics — the only women honored with the distinction since Maria Goeppert Mayer in 1963 and Marie Curie in 1903. In her PhD project that eventually led to the Nobel Prize, Strickland had cited Goeppert Mayer's work in multiphoton physics.

In her opening remarks, Strickland noted that she was speaking on behalf of Arthur Ashkin, who was awarded half the prize for the invention of optical tweezers, and her "esteemed colleague" Gérard Mourou, with whom she shared the prize for the development of a chirped-pulse amplitude (CPA) laser.

"Not everyone thinks physics is fun, but I do," Strickland told the Stockholm audience. A self-described "laser jock," she referred to Cyndi Lauper's hit song, ‘Girls Just Wanna Have Fun,' which was getting a lot of airplay when she was a graduate student in Mourou's group in the Laboratory for Laser Energetics (LLE) at University of Rochester. "They wanted to wait until the workday is done, but I wanna have fun while I'm working."

While in Stockholm, Strickland participated in the tradition of touring the Nobel Museum and autographing a chair in the museum café. That chair had also been signed in 2013 by the Canadian author Alice Munro, who had won the prize for literature. Another honored tradition is for Laureates to donate an artifact to the museum. Strickland donated an Nd:glass laser rod from the original CPA laser she and Mourou developed.

"It's hard to believe," said Strickland, "but my former colleague, Bill Donaldson, who still works at LLE in Rochester, found it in a drawer. It was in its original box, with handwriting stating it was for the 7mm Quantel Laser."

In her talk Sunday night, Strickland shared the story of finally measuring the compressed pulse width of the amplified pulses with a colleague who had wheeled a streak camera into her lab one evening.

"I will never forget that night," she said. "It is truly an amazing feeling when you know that you have built something that no one else ever has and it actually works. There really is no excitement quite like it — except for maybe getting woken up at 5 in the morning because the Royal Swedish Academy of Sciences and the Nobel Foundation also think it was an exciting moment for the field of laser physics."

Among her slides, Strickland shared an image from the ceremony of her with 2013 SPIE President Bill Arnold and his sister Frances Arnold of Cal Tech who was awarded the Nobel Prize in Chemistry for "the directed evolution of enzymes." Arnold was the fifth woman in history to win the prize for chemistry - not a bad day in Stockholm for women in science.

Hooked from the start
In the acknowledgments section of her PhD thesis, "Development of an Ultra-Bright Laser and an Application to Multi-Photon Ionization," Strickland credited her father, an electrical engineer; her mother, an English teacher; and her siblings who "continually supported and encouraged me through all my years of education."

When she was about five years old, Strickland's father took her to the Ontario Science Centre, where he showed her the museum's laser exhibit. "You'll want to see this, he said. "Lasers are the way of the future." Strickland barely remembers seeing that laser, but her curiosity and interest were captured. Later, as an undergraduate student at McMaster University, she was torn between electrical engineering, which offered more jobs, and physics, which offered more fun. Strickland chose fun.

"I think experimental physics is especially fun," said Strickland, "because not only do you get to solve puzzles about the universe or on Earth, there are really cool toys in the lab. In my case, I get to play with high-intensity lasers that can do magical things like take one color of laser light and turn it into a rainbow of colors. That's just one of the amazing things we get to see in our laser labs."

While working toward her graduate degree at University of Rochester, a fellow Canadian took Strickland to Mourou's lab where she first saw the red and green lasers and thought, "it's like working around a Christmas tree all the time. How fabulous is that?"

Mourou became her PhD supervisor and it was he who dreamed up the idea of increasing laser intensity by orders of magnitude. It was Strickland's job to "take Gérard's beautiful idea and make it a reality." During that process, she built a pulse stretcher, then a laser amplifier, and finally a pulse compressor. To do all this, she had to learn such things as how to cleave optical fiber, machine various parts, and do a lot of plumbing.

She then had to measure the pulse durations and the frequency spectrum. "Not all the measurements showed what we expected," she said. "We had to figure out the problems and then a way around them. That was the fun part. We scientists like to puzzle as to why something is or isn't working."

Working together, Strickland and Mourou paved the way toward the most intense laser pulses ever created. Their research has several applications today in industry and medicine — including cutting the cornea in laser eye surgery and machining small glass parts for use in cell phones.

Open fields: no barriers
Since winning the Nobel Prize, Strickland has had several speaking engagements and has been through several interviews where she has been asked every question in the universe — including "what did you donate to the Nobel Museum?"

Her message often turns to young people, especially girls, pursuing careers in science. When she learned she was only the third woman to win the Nobel Prize in Physics, her reaction was, "Is that all? I thought there might have been more. Obviously, we need to celebrate women physicists, because we're out there."

Strickland says she never encountered blatant sexism in her career; that she's "always been treated like an equal among male scientists." As she discusses her experiences in the lab and in academia, she says she simply ignored any prejudices.

"I always went through with blinders on," said Strickland in a talk at University of Waterloo. "I don't think I purposely put the blinders on, but if I want something, I just see what I want, and if people say no, I think they're wrong. So, that's my advice — if someone says something you don't believe in, just think they're wrong and you're right and keep going. That's just pretty much the way I always think." She added that she doesn't think there should be barriers for anybody to do what they're good at, "because that's how the world works best, if we're all out there doing our best."

Strickland ended her plenary talk with pictures of the Nobel winners seated with the Swedish royal family at a long, well decked-out dinner table in the palace. The rule is everyone sits boy-girl-boy, so Strickland was seated between the King and one of the princes.

"Somehow I went from being a student just trying to finish a PhD to landing in the middle of a fairytale," she said.

This article originally appeared in the 2019 Photonics West Show Daily.