It’s lucky for science that Gérard Mourou, professor emeritus of engineering at the University of Michigan in Ann Arbor, can’t stop mulling over technical questions, not even while skiing with his wife, Marcelle. On the chairlift one day in 1985, Mourou thought about a new paper that described a process for stretching and compressing light pulses. It gave him an idea.
Abandoning the slopes, he returned to the Laboratory for Laser Energetics at the University of Rochester in New York and tasked a student with proving the theory expressed in the article.
Before long, Mourou and his students — most notably Donna Strickland — created a light pulse of unprecedented power. “It was at night and we were jubilant,” he wrote. Hearing a “noisy celebration,” the lab’s director stopped in to inquire.
“I told him that we just had demonstrated the generation of one TW (terawatt) with a new amplification technique. It was a thousand times improvement in power over standard techniques and, moreover, this technique could be scaled to a much higher energy.”
The new advance, called Chirped Pulse Amplification, or CPA, became the basis for high-powered laser facilities worldwide.
In 1988, Mourou was recruited to the University of Michigan, where he founded the Center for Ultrafast Optical Science. He taught at U-M for 16 years while continuing to refine the principles and techniques of lasers.
As a compelling new development, lasers presented the opportunity for pioneering research. While lasers may have destructive potential, scientists continue to find useful industrial and commercial applications, from laser pointers to dermatology treatments.
When Mourou moved to U-M, some students from the University of Rochester followed. One, Ted Norris, is now the Gérard Mourou Collegiate Professor of Electrical Engineering.
Continued research at U-M with the Hercules laser revealed previously unknown properties such as the creation of “filaments” that help the beam cohere. Petawatt beams — “about 1,000 times the total power of the worldwide grid,” Mourou has explained — have been achieved elsewhere, and the 1,000-times-more powerful nexawatt laser has been proposed.
Now 75, Mourou most recently coordinated the Extreme Light Infrastructure, a group of powerful lasers in Europe. In recognition of their work, Mourou and Strickland received the 2018 Nobel Prize for Physics with Arthur Ashkin. Mourou and Strickland were cited “for their method of generating high-intensity, ultrashort optical pulses.”
“The ultrabrief, ultrasharp beams can be used to make extremely precise cuts, so their technique is now used in laser machining and enables doctors to perform millions of corrective laser eye surgeries,” The Guardian reported. In his Nobel address, Mourou said laser pulses could potentially neutralize nuclear waste in just a few minutes. “The idea is to transmute this nuclear waste into new forms of atoms which don’t have the problem of radioactivity. What you have to do is to change the makeup of the nucleus.”
In the realm of pure research, a laser can look inside chemical and physical reactions — including, in the latter case, the study of antimatter. Of more immediate practicality, applications for cancer treatment are being pursued. Meanwhile, Mourou continues his research and acts as an ambassador for lasers, the inevitable result of his self-described “passion for extreme light.”