"Techniques resulting from the work of Pierre Agostini, Ferenc Krausz and Anne L'Huillier let scientists capture the motions of subatomic particles moving at impossible speeds.
The Nobel Prize in Physics was awarded to Pierre Agostini, Ferenc Krausz and Anne L'Huillier on Tuesday for techniques that illuminate the subatomic realm of electrons, providing a new perspective into a previously unexplored domain.
Electrons move at a whopping 43 miles a second. This speed has long made them impossible to study. The new experimental techniques created by the three scientist-laureates use short light pulses to capture an electron's movement at a single moment in time.
Think of a rotating fan at its highest speed: each blade is a blur. But if you point a strobe light at the fan, every flash will illuminate a frozen moment in time. As the flashes get shorter, more information about the fan is revealed.
To study the movement of electrons, the scientists had to use pulses of light that last only on the scale of attoseconds; an attosecond is one quintillionth of a second. The number of attoseconds in a single second is the same as the number of all the seconds that have elapsed since the universe burst into existence 13.8 billion years ago, according to the Royal Swedish Academy of Sciences, which awards the Nobel Prizes.
Eva Olsson, the chair of the Nobel Committee for Physics, said at a news conference on Tuesday that attosecond science "allows us to address fundamental questions" by measuring the relative positions of electrons in an atom.
Who are the winners?
Pierre Agostini, 82, is an emeritus professor at Ohio State University. He was educated in France.
Ferenc Krausz, 61, is director at the Max Planck Institute of Quantum Optics in Germany and a professor of experimental physics at Ludwig Maximilian University of Munich. He was born in Hungary.
Anne L'Huillier, 65, is a professor at Lund University in Sweden. She was born in Paris.
Dr. L'Huillier is the fifth woman to win the prize in Physics. The last woman to be recognized in the category was Andrea Ghez, an astrophysicist, in 2020.
Why did the committee say they were receiving the prize?
In 1987, Dr. L'Huillier laid the groundwork for investigation at the electron level by studying the effects of shining an intense laser through noble gases -- odorless, colorless, single-atom gases with low chemical reactivity. She discovered that the laser energized the gas, causing it to emit light at special frequencies.
Light is an electromagnetic wave, characterized by crests and dips whose distances relate to its frequency. These waves interact with each other as they travel, becoming more intense when the crests meet one another, and canceling each other out when a crest coincides with a dip. Dr. L'Huillier's work revealed the potential for these waves to line up just right, so as to create short pulses of light that could be used to study electrons.
But scientists were not sure how to combine these waves or measure such short pulses until 2001, when Dr. Agostini successfully demonstrated a method to produce a series of light pulses lasting 250 attoseconds. Independently, Dr. Krausz used a different technique to generate a single pulse of light, lasting 650 attoseconds. Subsequent advances have made it possible to achieve pulses as short as a few dozen attoseconds today.
Scientists can use this subatomic "strobe light" to take a snapshot of the inner workings of atoms. The effect won't produce actual images, but will reveal information about the relative positions of electrons around the atom or within molecules, and how much time it takes to pull them away from the nucleus they are bound to. Attosecond physics will also allow scientists to measure the timing of electrons being released from a material when light shines on it. Albert Einstein received the 1921 Nobel Prize in Physics for establishing the theory of this phenomenon, known as the photoelectric effect.
Accessing the ultrafast world of electron motion may also lead to advances in circuitry, drug design and the materials used for batteries, as well as noninvasive diagnostic tools in medicine.
Louis DiMauro, a physicist at Ohio State University, described Dr. L'Huillier's work as a suite of "elegant experiments and superb theory" that laid the foundation for the potential of electron motion capture. Dr. Agostini and Dr. Krausz then followed the challenging prescription to make this decades-long dream a revolutionary reality, he said.
The discovery sheds light on physical systems that occur at short time scales, and provides physicists with "a new tool to tame the microscopic world," Ignacio Cirac, a theoretical physicist at the Max Planck Institute of Quantum Optics and a colleague of Dr. Krausz, wrote in an email.
These "stroboscopic images of electrons, like of dancers in a club" have "sparked the creativity" of researchers around the world, according to Jan-Michael Rost, the director of the Max Planck Institute for the Physics of Complex Systems.
"Physics, throughout history, has advanced every time we make a quantum leap in precision," Dr. DiMauro said. "In this case, the quantum leap was a jump into the attosecond time domain."
What did the laureates say about winning the prize?
Dr. L'Huillier was in the middle of a break during a class she was teaching when her phone rang, according to the Nobel Foundation. She took the call in a corner and learned the news.
"I am so happy to get this prize," she said. "It's incredible."
The new laureate then went back to her teaching, though "the last half-hour of my lecture was a bit difficult to do," Dr. L'Huillier said during the announcement ceremony.
"As you know, there are not so many women that get this prize," she added. "So it's very, very special."
Dr. Krausz was preparing physics lectures at his home when he got the call. "I just wasn't sure whether I'm dreaming or whether it's reality," he said. His first thoughts were with the many friends and collaborators who "have directly or indirectly contributed to this," he said.
The Nobel Foundation was unable to reach Pierre Agostini, who was in Paris at the time of the announcement. Dr. Agostini found out about the win from his daughter, who called to ask if the news was true. "I thought it was some kind of mistake, but it's not," he said, adding that his first inclination was to hide away from the newfound fame.
"Why they chose to award this kind of research now is sort of a mystery," said Dr. Agostini, who ran the experiments leading to the prize over 20 years ago. But, he added, it's "better late than never."" [1]
1. 3 Scientists Who Captured Electrons in 'Strobe Light': [Foreign Desk]. Bubola, Emma; Miller, Katrina. New York Times, Late Edition (East Coast); New York, N.Y.. 04 Oct 2023: A.9.
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