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There is a slight difference between “femtosecond” and “attosecond,” but both led researchers to win the Nobel Prize. The “femtosecond” (one millionth of a billionth of a second) awarded Egyptian scientist Ahmed Zewail the “Nobel Prize in Chemistry” in 1999, while Frenchman Pierre Agostini, Austro-Hungarian Ferenc Krause and French-Swedish Ann Lhuillier each won. “Nobel Prize in Physics” in 2023

Zewail invented a microscope that could shoot laser beams in “femtoseconds” so that molecules could be seen during chemical reactions. But three scientists, who won the Nobel Prize in Physics, “have demonstrated a way to create ultra-short bursts of light that can be used to measure rapid processes in which electrons move or transfer energy,” according to a report from the Royal Swedish Academy. The science that awards the Nobel Prize for Physics.

Over decades, the research conducted by the three laureates has allowed them to investigate fast processes that were previously impossible to follow. This new technology is critical to understanding and controlling how electrons behave in matter.

Eva Olsen, head of the Nobel Physics Committee, told a press conference on Tuesday that attosecond science allows us to address fundamental questions such as the time scale of the photoelectric effect, for which Albert Einstein won the 1921 Nobel Prize in Physics.

Members of the team explained that “an attosecond is so short that one second is the number of seconds that have passed since the universe began 13.8 billion years ago,” adding that “contributions by the winners made it possible to explore processes that were very fast, and previously impossible to follow.” ».

What did the winners give?

Agostini is a professor at Ohio State University in the US and Krause is a director at the Max Planck Institute in Germany. As for Lhuillier, the fifth woman to win the Nobel Prize in Physics since 1901, she works as a professor at Lund University in Sweden.

Experiments by Nobel laureates in physics produced pulses of light so short that they were measured in totoseconds, demonstrating that these pulses could be used to provide images of processes within atoms and molecules.

Anne Lhuillier discovered a new effect of the interaction of laser light with atoms in a gas, while Pierre Agostini succeeded in generating and studying continuous light pulses, each pulse lasting only 250 attoseconds. At the same time, Ferenc Krause was working on another type of experiment that managed to isolate a light pulse lasting 650 attoseconds. The laureates’ contributions made it possible to explore processes that were previously too fast and impractical, according to the committee’s report.

Bob Rosner, president of the American Physical Society and professor at the University of California, said of the award: “The winners were able to produce flashes of light that allowed us to see the assembly of molecules and how things fit together. to make a molecule.” These movements “happen so quickly that we don’t really know how they happen or what the sequence of events is,” Rosner told CNN.

The laureates’ work means scientists can now observe how these movements occur, he added. He continued: “Imagine building a house. You have a foundation, walls, roof, etc. Anything complex has a sequence. “For a molecule, if you don’t get the sequence right, you can’t assemble it.”

For his part, Michael Moloney, CEO of the American Institute of Physics, said: “These techniques allow us to see atoms down to the size of electrons, which previously moved so quickly that we couldn’t see them. We don’t have light fast enough to detect this movement,” British newspaper, Financial Times reported.

Meanwhile, Mitti Attatori, head of Cambridge University’s physics lab, added, “Decades of searching for short, intense pulses have allowed us to learn how matter behaves on shorter and shorter timescales. “This is our highest precision measure of how the world works.”

“Attoseconds” and the motion of electrons

An “attosecond” is 1,000 times faster than a “femtosecond” and is the shortest time scale scientists have ever achieved.

The femtosecond is used to measure very fast phenomena such as the interactions of light and matter, and is also used in advanced laser technologies, the attosecond is used to measure phenomena that occur at speeds faster than the femtosecond. Electrons.

Electrons, tiny particles that orbit the nucleus of an atom, move at incredibly high speeds, making them difficult to observe. However, by studying these particles in fractions of a second called attoseconds, the researchers were able to get a “fuzzy” view of their behavior. According to the Royal Swedish Academy of Sciences, this breakthrough allows new scientific fields to be explored, and has the potential for practical applications in areas such as electronics and diagnostics.

According to the Nobel Committee’s report, fast-moving events flow into one another as a person perceives them, just as a film with still images is seen as continuous motion. If we want to investigate very short events, we need special technology. In the world of electrons, transitions occur in a few tenths of an attosecond.

Just as the naked human eye cannot distinguish the individual strokes of a hummingbird’s wing, the team explained that until this achievement, scientists had not been able to observe or measure the individual motions of an electron. Fast movements tend to blur together so that very short events cannot be noticed.

“The faster the event happens, the faster you can photograph if you want to capture the moment,” the team said. “The same principle applies to trying to capture a quick snapshot of the electrons’ movements.”

Possible applications

The Nobel report indicated that there are potential applications for attosecond pulses in various fields. In electronics, for example, it is important to understand and control how electrons in a material behave. Totosecond pulses can also be used to identify various molecules, such as in medical diagnostics.

The work of the three winners will pave the way for potential applications in fields including electronics and medicine, said Eva Olsson, adding, “We can now open the door to the world of electronics.” Attosecond physics allows us to understand the mechanisms governed by electrons. The next step will be to take advantage of it,” he said.

Meanwhile, Anne Lhuillier, the fifth woman out of 225 Nobel laureates in physics, said that the practical use of totosecond lasers could be as an imaging tool in the semiconductor industry. Lhuillier made the first breakthrough in a series of discoveries leading to attosecond physics at the University of Paris-Saclay in France in 1987, and continued his research after moving to Sweden in the 1990s. “We’re just now seeing applications appear,” he said. “Basic research is very important and should be funded.”

The Royal Swedish Academy of Sciences said Ferenc Krause’s lab was “taking the first steps towards biological applications”. By combining attosecond physics with broadband optics, researchers are developing new ways to detect changes in the molecular composition of biological fluids, including diagnosing diseases from blood samples.