This Nobel Laureate Paved the Way for High-Intensity Lasers

Growing up, Donna Strickland had one objective in thoughts: Earn a Ph.D. But she didn’t know what topic she needed to pursue till she started her undergraduate research in physics at McMaster University, in Hamilton, Ont., Canada. It was there that she received keen on learning lasers after taking a course on the topic.

The matter appeared “really cool—like something from a science-fiction novel,” Strickland says. Little did she know that her newfound ardour would someday earn her a Nobel Prize in physics.

While conducting analysis in optics for her doctorate on the University of Rochester, in New York, Strickland labored with French physicist Gérard Mourou, a laser pioneer and Nobel laureate. Mourou led the event of the Extreme Light Infrastructure community of physics laboratories constructed to generate and research intense laser mild. Together, whereas experimenting with how one can improve a laser’s peak energy with out damaging it, they invented the chirped-pulse amplification approach. CPA, which produces brief laser pulses that attain excessive depth, now could be utilized in corrective eye surgical procedure, medical imaging, smartphone manufacturing, and lots of extra functions.

Strickland and Mourou shared the 2018 Nobel Prize in physics with IEEE Life Fellow Arthur Ashkin, who invented a separate expertise: “optical tweezers,” which use low-power laser beams to govern residing cells and different tiny objects.

Receiving the Nobel was “life-changing,” Strickland says, including, “Your life can change in a single day without you being ready for it.”

Her invention additionally earned her this yr’s IEEE Honorary Membership, which is sponsored by IEEE. She says the popularity is particular as a result of her colleagues nominated her for it.

“Donna’s work has been transformative. Her seminal research on chirped-pulse amplification is the gold standard of research,” certainly one of her award endorsers stated. “Additionally, she is a true role model to legions of engineers around the world. She is an extremely giving person and a shining example of what an IEEE honorary member should be.”

Strickland is a physics professor on the University of Waterloo, in Ontario, the place she leads a bunch of researchers that’s creating high-intensity laser techniques for nonlinear optics investigations corresponding to producing midinfrared pulses by distinction frequency mixing and learning the multifrequency Raman era approach.

Donna Strickland receives the 2018 Nobel Prize in physics from King Carl Gustaf of Sweden, on the Stockholm Concert Hall.Henrik Montgomery/TT News Agency/Getty Images

Paving the way in which for high-intensity lasers

After graduating in 1981 with a bachelor’s engineering diploma in physics from McMaster, Strickland moved to New York to pursue a doctorate in optics on the University of Rochester, which on the time was thought of one of many prime faculties for learning laser optics. She joined Mourou on the college’s Laboratory for Laser Energetics, the place he was on the lookout for methods to extend lasers’ depth (its optical energy) with out damaging the gadget.

Pulsed lasers can focus mild onto a small space for a short while to supply energy. Peak intensities elevated quickly for a number of years after physicist Theodore Maiman demonstrated the first laser in 1960. But the intensities plateaued for greater than a decade after 1970 as a result of amplifying the sunshine previous a sure level broken the laser.

In his analysis on how mild interacts with matter, Mourou hypothesized in 1983 that spacing out and augmenting pulses earlier than bringing them again collectively may lead to higher-intensity laser pulses with out harm. But he didn’t know how one can accomplish it, Strickland says. So for her doctoral analysis, she examined his speculation with completely different laser techniques. None of her experiments labored, nonetheless.

“Donna is a true role model to legions of engineers around the world. She is an extremely giving person and a shining example of what an IEEE honorary member should be.”

It wasn’t till Strickland and Mourou attended the 1984 International Conference on Ultrafast Phenomena that they discovered the answer. The biannual occasion brings collectively scientists who’re creating instruments, methodologies, and methods used to check processes in atoms, molecules, or supplies that happen in millionths of a billionth of a second or sooner.

Strickland and Mourou attended a presentation on the convention in regards to the newly developed optical fiber pulse compression of neodymium-doped yttrium aluminum garnet (Nd:YAG) lasers. With the approach, 100-picosecond pulses could possibly be compressed to 1 ps utilizing nonlinear optics in an optical fiber to extend a laser’s spectral bandwidth. It was discovered that compression was most profitable when the pulses have been allowed to stretch via dispersion within the fiber.

“I was using those same lasers for my experiments,” Strickland recalled.

She and Mourou found out how she may safely create the high-intensity pulse: The pulse wanted to be stretched earlier than it was amplified quite than afterward, as what had been executed. Stretching the heartbeat meant it could possibly be recompressed to supply the specified depth.

To check her idea, Stickland and Mourou constructed a system on the Laboratory for Laser Energetics that was composed of a 2-watt Nd:YAG laser, 1.4 kilometers of optical fiber, an amplifier, and a pair of parallel gratings.

The Nd:YAG laser pumped a brief pulse at 100 ps into the optical fiber. As the rate of sunshine relies on wavelength, the crimson element of the sunshine propagates sooner than the blue inside the fiber.

That is known as a “chirped pulse,” Strickland says, as a result of a chook’s chirp has the same frequency construction.

The chirped pulse makes the length of the heartbeat longer and spreads out the depth in order that it doesn’t harm the laser. The stretched, lower-energy density pulse was then amplified and handed via a pair of parallel diffraction gratings—which allowed the trailing blue element to catch as much as the crimson. Both have been reassembled by reflecting off the gratings. The reassembled pulse was thrice extra highly effective than the unique one, Stickland says.

The approach, which was named after the chirped pulse, has since paved the way in which for the shortest and most intense laser pulses ever created, making it potential to construct extra compact and exact laser techniques.

Strickland and Mourou’s 1985 paper “Compression of Amplified Chirped Optical Pulses,” was revealed in Optics Communications. It was Strickland’s first revealed analysis paper.

From Princeton to Waterloo

After serving to develop CPA, Strickland nonetheless wasn’t certain what profession path to pursue. She sought recommendation from her colleagues, and one advised her that Paul Corkum, a physicist who labored within the Canadian National Research Council’s ultrafast-phenomena division, was getting his first postdoctoral analysis fellow that yr. Corkum, who specialised in laser science, pioneered the event of attosecond physics. Strickland preferred the sound of that.

“I remember telling the other doctoral candidates in my research lab that Corkum may not know my name yet, but I was going to be his second postdoc,” she says. She received her dream job in 1988 and labored for him for 3 years.

In 1991 she turned a physicist on the Lawrence Livermore National Laboratory, a U.S. Department of Energy facility in California.

While she lived on the West Coast, her husband, a physicist, lived on the East Coast, working at Bell Labs in Murray Hill, N.J.

After spending a yr aside, Strickland moved to New Jersey to affix the technical employees at Princeton’s Advanced Technology Center for Photonics and Opto-electronic Materials. She labored with electrical engineers, mechanical engineers, and chemists there, she says, and “if they had a laser, I helped them out.” She helped a professor construct a CPA laser and assisted a analysis group that was conducting nonlinear optical characterization of a brand new pulse amplifying materials.

Strickland says she thought she’d be working at Princeton till she retired, however after her husband left Bell Labs in 1996, they returned to Canada. Strickland joined the University of Waterloo’s physics division as an assistant professor. She was promoted to affiliate professor in 2002. From 2007 to 2013, she served as affiliate chair of the division.

“When I was young, I just wanted to get a Ph.D. and stay in school,” Strickland says. “Being a professor is the next best thing to being a student.”

She acquired the IEEE Honorary Membership on 5 May on the IEEE Vision, Innovation, and Challenges Summit and Honors Ceremony, held on the Hilton Atlanta.