From lasers to a Nobel Prize: A conversation with Donna Strickland
Virtually 5 years after profitable the Nobel Prize in Physics, Donna Strickland, Canadian physicist and professor on the College of Waterloo, says it’s been a whirlwind. “My life is totally totally different,” she mentioned throughout our interview. “I wasn’t anticipating it in any respect.”
Earlier this month, Strickland was visiting Vienna and Berlin as a part of the Lise Meitner Lectures hosted by the German Bodily Society, and had a quick window by which she was obtainable to talk with members of the press. Receiving an invite to interview a Nobel Laureate is an thrilling prospect, and whereas ready for her arrival, I’ll admit my nerves had been operating excessive. However Strickland instantly put the room relaxed along with her pleasant and easy-going perspective. “Oh, you bought doughnuts!” she mentioned upon arriving. “Is that as a result of I’m Canadian?”
She now receives numerous invites to talk around the globe, has met rock stars, the Pope, astronauts, and through her Berlin lecture, confirmed an image from the Nobel banquet by which she was seated and enthusiastically gesturing subsequent to the King of Sweden. “I don’t bear in mind what I used to be explaining, nevertheless it wasn’t physics,” she mentioned, laughing. “These persons are not essentially going to recollect assembly me, however I’ll bear in mind assembly them. [As a laureate], you’ve got these experiences {that a} regular scientist doesn’t have.”
The morning of the announcement, she acquired a name at 5:15 AM alerting her to the truth that she had simply gained a Nobel Prize. “After the announcement, my e-mail simply went ‘ding, ding, ding, ding, ding’, and emails got here in from all around the globe. Folks that I had not heard from since elementary faculty had been getting in contact, after which the media requests began coming in,” she mentioned.
“Not like at a college like Stanford, the place there are media folks that keep awake till the announcement to search out out if [someone from the university] goes to win (as a result of they achieve this typically), Waterloo has by no means gained one earlier than, so my communications particular person didn’t get up till 7:00 AM. From six to seven, I used to be on my own making an attempt to reply media questions, and I didn’t know what I used to be doing.
“It was a busy morning; I had plumbers there who needed to shut my water off, I had my neighbor there with an enormous bouquet of flowers, I had a photographer making an attempt to take footage, and I had The Globe and Mail, Canada’s huge newspaper, on the cellphone with me. It was loopy.”
A profitable thought: Chirped pulse amplification
Strickland’s win got here on account of her pioneering work on ultra-short but extraordinarily high-intensity laser pulses, which she and her Ph.D. supervisor on the College of Rochester, Gérard Mourou, dubbed “chirped pulse amplification”. This work was printed in her debut paper in 1985. “I used to be the primary one that wanted the [laser] pulse to be quick with excessive energy,” she mentioned throughout her lecture given the subsequent day. “I needed to make the particular laser.”
From their software in surgical procedure, to smartphone know-how, LiDAR methods, barcode scanners, and fiber optics, lasers play a significant position in quite a few areas of our lives. For a lot of functions, a laser’s energy — the quantity of vitality it emits over a given time — issues.
It’s lengthy been identified that when a laser’s gentle depth (how a lot energy is concentrated in a given space) reaches some extent after which it begins to behave in ways in which classical physics can’t clarify, creating attention-grabbing results. The extra energy you’ve got, the extra depth that’s obtainable, and the extra atypical behaviors often called nonlinear optical phenomena that may be explored.
Nonetheless, within the Nineteen Sixties, scientists hit a wall of their efforts to provide lasers with ever-increasing depth. At a sure degree, laser gentle can’t be intensified additional as a result of a phenomenon often called Kerr-lens self-focusing. This impact happens when a high-intensity laser is targeted by a medium and causes its refractive index to alter, which ends up in even tighter beam focus over a smaller space. Whereas this has some useful software in areas equivalent to laser slicing, it prevented scientists from rising laser depth with out inflicting harm to the gear.
Chirped pulse amplification helped break by this barrier by diluting laser gentle in order that it may be amplified to a bigger complete energy with out reaching the identical dangerous intensities. It does so by first stretching laser pulses by time by introducing “chirp” into the sign. That is completed utilizing a prism or a diffraction grating to disperse the laser pulse into its constituent colours, sending the longer wavelengths first and the shorter wavelengths final. This stretching reduces the depth of the heart beat, which is handed by an amplifier, after which by a reversed set of gratings to recombine the longer and shorter wavelengths right into a single pulse that now has amplified energy with intensities inconceivable to attain safely utilizing direct amplification.
Since 2001, over 24 million corrective eye surgical procedures have been carried out utilizing Strickland and Mourou’s excessive pulse laser. “Chirped pulse amplification modified energy by orders of magnitude, and it modified how gentle and matter work together,” she mentioned throughout the interview. “I used to be making an attempt to do a excessive order, nonlinear optical experiment, we needed to see if we might push [the laser] larger.
“We knew it might be huge within the area of high-intensity laser physics, however I don’t suppose we thought our functions result in a Nobel Prize.”
Making science accessible
Strickland’s lecture, unofficially titled, “Why was I the fortunate pupil that gained the Nobel Prize?“, was fascinating. She managed to make complicated scientific ideas accessible to a basic viewers (a lot appreciated as a non-physicist myself), whereas weaving in entertaining anecdotes.
As an illustration, she shared the amusing story of how one night time her lab mate had clandestinely climbed by the constructing’s air ducts to convey the fiber cables she wanted into the lab the place she was conducting her experiments. She additionally recounted the time when she needed to unspool 2.2 km of fiber to be able to be certain that the laser gentle was certainly popping out on the different finish, solely to find that she had damaged it 1.4 km in. “Carry on going, don’t let little issues cease you,” was her recommendation to the viewers.
Strickland has been vocal up to now concerning the want for scientists to speak their work to most of the people to be able to enhance scientific literacy and understanding. “I don’t suppose [the public] must know actually technical physics, however they should perceive the position of science in society, and I don’t know that individuals these days in North America actually perceive it,” she mentioned.
“After I’ve traveled to Asia, I’ve been very impressed with how in tune they’re with their scientists. I used to be amazed that throughout the Nobel Prize week, there was a Japanese winner my 12 months, and he was surrounded by six to eight Japanese media individuals your complete week, not simply the day he gained — I don’t know the way he didn’t lose his thoughts however I assumed, ‘Oh my goodness, this man is sort of a rock star in Japan’.
“Years in the past, I informed my children after they had been in highschool that I used to be well-known, and my children mentioned if you wish to suppose you’re well-known, then go forward,” she mentioned laughing. “And after I gained the Nobel Prize I requested, can I say it now?
“[But] no American or Canadian media got here to Sweden, and I began to essentially take into consideration how totally different Asia appears at science in comparison with North America, and I believe we might be taught one thing from that. I believe the general public wants to grasp how a lot science may also help the financial system — Korea is my favourite instance of how a lot they’ve used science to spice up their financial system.
“I’ve additionally been dismayed at how too many individuals now take into consideration science from a political standpoint, which is so weird as a result of most scientists would say there needs to be no politics in science. Relying in your politics, you do or don’t imagine in local weather change, otherwise you would or wouldn’t put on a masks throughout COVID-19, and I believe we’ve to begin letting individuals know extra concerning the scientific course of to allow them to suppose for themselves what’s greatest.”
A societal shift
As one in all solely 4 ladies to have ever gained the Nobel Prize in Physics within the award’s 100-year-plus historical past, questions round gender fairness and the underrepresentation of girls in STEM inevitably floor.
An editorial printed in Nature Critiques Physics acknowledged that regardless of progress being made lately, “the under-representation of girls in science, and particularly in physics, is profound sufficient that we don’t want detailed statistics to see its existence.”
In an interview held throughout Nobel Prize week, Strickland described not having had a feminine professor, as both an undergrad or graduate pupil. “Now, there are six of us, I imagine, in my division of 40,” she mentioned. “That’s nonetheless solely […] 15% and it’s not as excessive correctly, however the truth that there are even six ladies as an alternative of zero is sort of a change.”
Quite a few research have explored the elements that result in these developments regardless of sustained investments and supported efforts to enhance the illustration of women and girls in STEM. The issue is multi-faceted and sophisticated, and based on Strickland, requires a major societal shift to essentially tackle it.
“So as to change the ratio of women and men within the pure sciences, society must care,” mentioned Strickland throughout our interview. “Individuals typically ask why I believe extra ladies don’t do physics and […] the one time I ever heard an evidence that made sense to me was when one in all my male colleagues mentioned, ‘Nicely, what can we do physics for? It’s not for the cash, we don’t receives a commission in addition to different fields. It’s so we are able to go to our conferences to say, look what I did!’ And males are taught from delivery to face up and say, ‘Look what I did!’, and ladies will not be.”
“Till we modify that and make that an amazing aim of ours, [the gender ratio] will keep the identical,” she added.
What’s subsequent?
All of the occasions which have taken place during the last 5 years have been surreal and unusual for somebody who’s tried to have a quiet life, commented Strickland. “I’m nonetheless making an attempt to verify the pulses are environment friendly,” she mentioned. “I’ve a colleague proper subsequent door [at Waterloo] who, possibly 20 years in the past, I informed I might attempt to make single femtosecond laser pulses to do his molecular films.
“He’s nonetheless ready, mainly it’s gone nowhere as a result of I’m by no means within the lab anymore. However I’m nonetheless working in direction of it, whether or not I obtain it or not, I’m undecided.”
She additionally described a collaboration with Toshi Tajima, the pioneering theoretical plasma physicist at the moment working on the College of California, Irvine, identified for his work with John M. Dawson in 1979 on Laser Wakefield Acceleration — a technique for producing high-energy electron beams. Up to now, this technique has discovered software in radiography, radioisotope manufacturing, nuclear physics, and the doable transmutation of nuclear waste.
“The primary use of massive lasers, ” defined Strickland, “is to be used in Wakefield Acceleration. [Tajima] now needs to do it at low ranges with my fiber lasers to see if we are able to use […] acceleration of electrons to take away tumors.”
Tumor elimination utilizing accelerated electrons normally requires surgeons to chop into layers of wholesome tissue to make sure that no cancerous tissue has been left behind. “They err on the aspect of taking an excessive amount of, however that may trigger issues,” mentioned Strickland. “[Tajima] hopes that we might use [my] lasers to depart the final layer. I’ll don’t have anything to do with the medical software — I don’t go wherever close to drugs as a result of I don’t like squishy — however I’m making an attempt to make a brand new sort of fiber supply that may keep quick and intense proper out of the fiber and never want gradient compressors.
“I’m additionally making an attempt to fill that hole the place there are only a few sources only for the enjoyable of it. I determine, if I do it individuals will come and use them. I identical to to have lasers that no one else has.”
Characteristic picture credit score: College of Waterloo
