Nobel Prize in physics awarded to trio for tools made of light

The 2018 Nobel Prize in physics was awarded Tuesday to Arthur Ashkin, Gérard Mourou and Donna Strickland for their pioneering work to turn lasers into powerful tools.

Ashkin, a researcher at Bell Laboratories in New Jersey, invented “optical tweezers” — focused beams of light that can be used to grab particles, atoms and even living cells and are now widely used to study the machinery of life.

Mourou, of École Polytechnique in France and the University of Michigan, and Strickland, of the University of Waterloo in Canada, “paved the way” for the most intense laser beams ever created by humans via a technique that stretches and then amplifies the light beam.

“Billions of people make daily use of optical disk drive, laser printers and optical scanners ... millions undergo laser surgery,” said Nobel committee member Olga Botner. “The laser is truly one of the many examples of how a so-called blue sky discovery in a fundamental science eventually may transform our daily lives.”

Strickland is the first woman to be awarded the physics prize since 1963, when Maria Goeppert-Mayer was recognized for her work on the structure of nuclei. Marie Curie won the physics prize in 1903 and the chemistry Nobel Prize in 1911. A reporter asked the professor what it felt like to be the third woman in history to win the prize.

“Really? Is that all? I thought there might have been more,” Strickland responded, sounding surprised.

Ashkin, 96, is the oldest person to be awarded the Nobel Prize. He would not be available for interviews, the committee said Tuesday morning; he was too busy working on his next paper.

In a laser beam, light waves are tightly focused, rather than mixing and scattering as they do in ordinary white light. Since the first laser was invented in 1960, scientists speculated that the energy of these focused beams could be put to work to move and manipulate objects — a real life version of Star Trek’s “tractor beams.”

“But this was science fiction for a very long time,” committee member Mats Larsson said.

Ashkin spent two decades studying the properties of lasers, first recognizing that objects could be drawn toward the center of a beam, where the radiation was most intense. (A committee member demonstrated this phenomenon during the news conference by using a hair dryer to suspend a pingpong ball in the air.) By further focusing the beam with a lens, he developed a “light trap” that could suspend a small spherical object at its center.

Ashkin used his new tool to hold a particle in place, then an atom, and, eventually, in 1987, a living bacterium. Ashkin even demonstrated that the tool could be used to reach into a cell without damaging the living system.

Atomic physicist Bill Phillips, who shared the Nobel Prize in 1997 for his work on cooling and trapping atoms with lasers, said that Ashkin’s discoveries were vital to his own research. “I feel like I owe a great debt to Art,” he said.

Also in the 1980s, Mourou and Strickland were working together at the University of Rochester to overcome a problem that had dogged laser research for decades: High-intensity laser beams tended to destroy the material used to amplify them. It was as though scientists were trying to boil water in a pot that couldn’t handle such high temperatures.

The Rochester researchers developed an elegant workaround, which they called “chirped pulse amplification.”

CPA has been used to take images of split-second processes, such as interactions between molecules and atoms.