The 2023 Nobel Prize in physics has been awarded to a team of scientists who created a ground-breaking technique using lasers to understand the extremely rapid movements of electrons, which were previously thought impossible to follow. Pierre Agostini, Ferenc Krausz and Anne L’Huillier “demonstrated a way to create extremely short pulses of light that can be used to measure the rapid processes in which electrons move or change energy,” the Nobel committee said when the prize was announced in Stockholm on Tuesday. It praised the laureates for giving “humanity new tools for exploring the world of electrons inside atoms and molecules.”
The movements of electrons inside atoms and molecules are so rapid that they are measured in attoseconds – an almost incomprehensibly short unit of time. An attosecond is a mind-bendingly short period of time. As the committee points out, the number of attoseconds that fit into one second – a timescale roughly equal to a heartbeat – is the same as the number of seconds that have passed since the birth of the universe.
However, it is these timescales that govern electron dynamics. It takes about 150 attoseconds for an electron to orbit the nucleus of a hydrogen atom, while it takes electrons a few hundred attoseconds to jump from one atom to another. “They were able to, in a sense, provide an illumination tool that allows us to watch the assembly of molecules: how things come together to make a molecule,” Bob Rosner, president of the American Physical Society and a professor at the University of Chicago, told CNN.
These movements “happen so quickly that normally we have no idea how they actually occur or what the sequence of events is,” said Rosner. But the laureates’ work means scientists can now observe how these movements happen, he added.
The three winners used precision lasers to generate ultra-short bursts of light. L’Huillier, a professor at Lund University in Sweden, discovered a new effect from a laser light’s interaction with atoms in a gas. Agostini, a professor at Ohio State University, and Krausz, a professor at the Max Planck Institute of Quantum Optics in Germany, then demonstrated that this effect can be used to create shorter pulses of light than were previously possible.
L’Huillier, who is only the fifth woman to win a Nobel Prize in Physics since the accolades were established in 1901, said she was teaching a class when she got the call from Stockholm this morning, only picking up the phone on the third or fourth time. “The last half hour of my lecture was a bit difficult to do,” L’Huillier told Hans Ellegren, secretary general of Royal Swedish Academy of Sciences, during the announcement news conference. Together, the trio’s experiments with lasers have allowed them to “capture the shortest of moments,” the committee said.
Just as the naked human eye cannot discern the individual beats of a hummingbird’s wing, until these breakthrough scientists were not able to observe or measure the individual movements of an electron, the committee explained. Rapid movements blur together, making extremely short events impossible to observe.
“The faster the event, the faster the picture needs to be taken if it is to capture the instant,” the committee said. “The same principle applies to trying to take a snapshot of the movements of electrons. “When asked about the potential applications of her research, L’Huillier said the first use is “to really understand when we look at electrons, and look at their properties. “The second one is much more practical and it’s coming. This radiation that we produce is also useful for the semiconductor industry as an imaging tool. So this is also coming with a practical application,” L’Huillier said.
Everything in the world – gases, solids, liquids – is made up of atoms, which contain a nucleus with electrons spinning around it. Olle Eriksson, a professor of theoretical magnetism at Uppsala University in Sweden and a member of the committee that awarded this year’s physics prize, compared the atom to flies hovering around a sugar cube.
“On the attosecond timescale, it is as if time stood still, everything is exactly fixed, except the electrons, and so the only thing you’ll see is the movement of those flies (electrons), not the sugar cubes themselves. This allows us to study the electrons and nothing else and the electrons are the ones that are responsible for all chemical binding,” he explained. The technique does not allow scientist to directly see electrons but works a little like a strobe light to image something that moves rapidly, allowing scientists to measure different attributes of the subatomic particles, which carry an electric charge.
Michael Moloney, the chief executive of the American Institute of Physics said that the discovery has “opened up a whole new window on our universe. “You can send a pulse into the material, a very, very short pulse and pulse after pulse. And that allows you to see then how the (electron’s) charge is moving around between molecules and within molecules and really understand the foundations of all chemical and physical reactions." This is another transformative moment in physics and in science, where a whole new (way) to probe the universe was opened up by the work of these three physicists, Moloney added.
Three scientists won the Nobel Prize in physics Tuesday for giving us the first split-second glimpse into the superfast world of spinning electrons, a field that could one day lead to better electronics or disease diagnoses. The award went to Pierre Agostini, emeritus professor at Ohio State University; Ferenc Krausz of the Max Planck Institute of Quantum Optics and Ludwig Maximilian University of Munich in Germany; and Anne L’Huillier of Lund University in Sweden. They were recognised for their study of the tiny part of each atom that races around the center and that is fundamental to virtually everything : chemistry, physics, our bodies and our gadgets.
Electrons move around so fast that they have been out of reach of human efforts to isolate them. But by looking at the tiniest fraction of a second possible — an attosecond, which is one-billionth of one-billionth of a second — scientists now have a “blurry” glimpse of them. That opens up whole new sciences, experts said.
“The electrons are really the workforce everywhere,” Nobel Committee member Mats Larsson said. “Once you can control and understand electrons, you have taken a very big step forward. “The three honorees' experiments “have given humanity new tools for exploring the world of electrons inside atoms and molecules,” according to the Royal Swedish Academy of Sciences, which announced the prize in Stockholm. They “have demonstrated a way to create extremely short pulses of light that can be used to measure the rapid processes in which electrons move or change energy.
“At the moment, this science is about understanding our universe, but the hope is that it will eventually have many practical applications. “This is an important field because it gives you possibilities to develop very fast electronics based on these short pulses,” he said. Another application under investigation, he said, was molecular fingerprinting of biological samples.
For example, Larrson said, very short pulses of light could be used to excite molecules within a blood sample Infrared light emitted by the molecules could be then detected with attosecond precision, offering scientists a way to identify minute changes in the blood.
“By doing this, there is the hope in the future that you will be able to capture whether a person has developed, for example, lung cancer, so that you have a very sensitive method, and if you can diagnose cancer at a very early stage treatment will be much more successful,” Larsson said. “This is a really well-deserved award to some of the pioneers of the field of attosecond science,” he said. “This capability is allowing us to investigate the very fastest electronic dynamics in matter that underpins photo physical and photochemical processes in all phases of matter.”
