For giving us the first split-second view into the extremely fast world of spinning electrons, three scientists shared the Nobel Prize in physics on Tuesday. This achievement could one day improve electronics or aid in the detection of diseases.
The prize was given to Ferenc Krausz, a Hungarian-born scientist, Anne L’Huillier, a French-Swedish physicist, and Pierre Agostini for their research on the microscopic component of each atom that revolves about the center and is essential to nearly everything, including chemistry, physics, human bodies, and technology.
Since electrons travel so quickly, human efforts to isolate them have been unsuccessful. However, by observing the smallest fraction of a second possible, scientists have gained a “blurry” view of electrons, which, according to experts, opens up completely new fields of study.
According to Mats Larsson, a member of the Nobel Committee, “the electrons are very fast, and the electrons are really the workforce in everywhere.” You have made great progress once you can manage and comprehend electrons.
L’Huillier, a professor at the Swedish Lund University, is the fifth woman to win the Nobel Prize in physics.
“For all the women, I say if you are interested, if you have a little bit of passion for this type of challenges, so just go for it,” she told the Associated Press.
WHAT DISCOVERY WON THE NOBEL PRIZE IN PHYSICS?
Similar to how photographers use quick shutter speeds to film a hummingbird eating, the scientists, who worked independently, utilized ever-quicker laser pulses to capture the atomic motion that occurs at such incredible rates—one quintillionth of a second, or an attosecond.
Just how tiny is that?
Let’s take one heartbeat, or one second, said Nobel Committee head Eva Olsson. That would need to be divided by 1,000 six times to reach the domain of the attosecond.
According to Nobel Committee member and physicist Mark Pearce, “there are as many attoseconds in a second as there are seconds since the Big Bang, 13.8 billion years ago.” But even when they “see” the electron, scientists can only see so much of it.
The 65-year-old L’Huillier added, “You can see whether it’s on the one side of a molecule or on the other. It’s still quite fuzzy.”The electrons are much more like waves, like water waves, than particles, and what we try to measure with our technique is the position of the crest of the waves,” she continued.
WHY DO ELECTRONS MATTER?
Because of “how the atoms bind together,” electrons are essential, according to L’Huillier. It is the site of chemical reactions. At a news conference, Krausz stated: “Electrons are, even though we can’t see them, omnipresent in our existence—our biological life, as well as our technical life, in our everyday life. In our biological life, electrons serve as the glue that holds atoms together to form molecules, which are the tiniest functional building blocks of every living thing.
Krausz added that knowing how they move will help you comprehend how they operate. This study is currently concerned with comprehending our cosmos, but it is hoped that it will someday have useful applications in electronics, illness diagnosis, and fundamental chemistry. Regardless of potential applications, L’Huillier claimed that her work demonstrates how crucial it is to work on fundamental science: Before potential applications in the actual world became clearer, she worked on it for 30 years.
HOW DID ANNE L’HUILLIER, FERENC KRAUSZ AND PIERRE AGOSTINI REACT?
When L’Huillier received the call informing her that she had won, her phone was on quiet, so she chose not to answer. At the time, she was teaching fundamental engineering physics to roughly 100 undergraduates at Lund. During a break, she examined it and called the Nobel Committee. She then resumed her teaching career. She told the AP, “I was very focused, forgot about the Nobel Prize, and tried to finish my lecture.” She left class a little early so she could speak at the press presentation at the Royal Swedish Academy of Sciences in Stockholm announcing the award.
“I am overjoyed to get this award because it is the most prestigious. She remarked at the news conference, “It’s incredible. “This prize is very special because, as you probably know, not many women have ever won it.”
L’Huillier is seen in a social media post from the Nobel organization clutching a phone to her ear. The tweet on X, formerly Twitter, read, “Dedicated teacher alert!” Even winning the 2023 Nobel Prize for Physics wouldn’t be able to separate Anne L’Huillier from her pupils. L’Huillier added that she was forbidden from telling the pupils what happened because the award was a secret at the time, but she claimed that they made an educated estimate. The Nobel Committee was unable to contact Agostini, an emeritus professor at Ohio State University, prior to the announcement of his win because he was in Paris.
“I haven’t received a call from the committee on the phone. It could be untrue. He laughed as he told the AP, “I don’t know. “I think Columbus is where the committee is looking for me,” The 82-year-old made a joke about how younger folks “would have appreciated it far more than me.” It is wonderful, although a little late for me. Nevertheless, he continued, “I don’t think I would have deserved it more earlier!” Krausz, of the Ludwig Maximilian University of Munich and the Max Planck Institute for Quantum Optics, told reporters he was perplexed. The 61-year-old stated, “I have been trying to figure out since 11 a.m…. whether I’m in reality or it’s just a long dream.”
Krausz typically doesn’t answer calls with “no caller ID” from organizations like the Nobel committee, but this time, he admitted, “I thought I’d try it and then it became clear that I can’t hang up so quickly.” Krausz and L’Huillier shared the coveted Wolf award in physics last year for their work with Paul Corkum, a researcher at the University of Ottawa. Only three people can win a Nobel Prize, and Krausz thought it was unfortunate Corkum was left out. According to Krausz, Corkum was essential in determining how to measure the brief laser bursts.
Experiments with light capture the shortest of moments
The three recipients of the 2023 Nobel Prize in Physics are being honored for their studies, which have provided mankind with unprecedented resources for examining the world of electrons inside atoms and molecules. The quick processes by which electrons move or alter their energy can be measured using the extremely brief light pulses that Pierre Agostini, Ferenc Krausz, and Anne L’Huillier have showed how to produce.
In the same way that a video made up of static images is seen by people as having continuous movement, fast-moving events appear to flow into one another. We need specialized technology if we wish to look into extremely brief events. Changes take place in the world of electrons in a few tenths of an attosecond, which is so brief that there are as many attoseconds in a second as there have been seconds since the universe’s creation. By creating light pulses that are so brief that they are measured in attoseconds, the laureates’ experiments have shown that these pulses may be utilized to capture images of processes occurring inside atoms and molecules.
In 1987, Anne L’Huillier observed that when she passed infrared laser light through a noble gas, numerous distinct light overtones appeared. Each overtone is an individual light wave that has a specific number of cycles for each cycle of the laser light. They are brought on by the laser light’s interaction with gas atoms, which causes some electrons to gain additional energy and release light as a result. In her ongoing investigation of this phenomenon, Anne L’Huillier has paved the way for later discoveries.
In 2001, Pierre Agostini was successful in creating and studying a string of subsequent light pulses, each lasting only 250 attoseconds. Ferenc Krausz was working on an experiment that allowed him to isolate a single light pulse with a duration of 650 attoseconds at the same time.
Due to the efforts of the laureates, it is now possible to study processes that were once hard to track because of their speed. The gateway to the realm of electrons is now open. We have the chance to comprehend electron-governed mechanisms thanks to attosecond physics. Utilizing them will be the next stage, according to Eva Olsson, chair of the physics Nobel Committee. There are a variety of potential applications. For instance, it’s crucial to comprehend and regulate how electrons act in a substance in electronics. In other contexts, such as in medical diagnostics, attosecond pulses can be utilized to distinguish between various substances.
Electrons in pulses of light
This year’s laureates have developed light flashes that are brief enough to record the incredibly quick motions of electrons. The interaction between atoms in a gas and laser light led to Anne L’Huillier’s discovery of a novel phenomenon. By using this effect, Pierre Agostini and Ferenc Krausz showed that it is possible to produce shorter light pulses than previously thought.
A hummingbird’s small wings can beat up to 80 times each second. We can only make out a whirring sound and hazy movement in this. Rapid movements blend together in the human senses, and incredibly brief events are impossible to see. To capture or describe these incredibly fleeting moments, we must apply technical trickery. Footing phenomena can be captured in great detail using strobe illumination and high-speed photography. The exposure time needed to capture a sharp image of a fighting hummingbird is substantially less than one wingbeat.
If you want to catch the moment, you must take the photo as quickly as the event does. Any measurement must be performed more quickly than the time it takes for the system under study to experience a discernible change; otherwise, the result is ambiguous. This same premise holds true for all techniques used to measure or represent rapid processes. The winners of this year’s award have carried out tests that show a technique for generating light pulses that are quick enough to record pictures of activities inside atoms and molecules.
The inherent time scale of an atom is extremely brief. Atoms in a molecule can move and rotate in femtoseconds, or millionths of a billionth of a second. These motions can be observed using the shortest laser pulses possible, but when complete atoms move, their huge, heavy nuclei, which move far more slowly than their light, nimble electrons, define the timescale. Since electrons travel so swiftly inside of atoms and molecules, changes take place in a femtosecond. Positions and energies in the universe of electrons change at rates of one to several hundred attoseconds, where an attosecond is one billionth of a billionth of a second.
Because an attosecond is so brief, there are exactly as many of them in one second as there have been seconds since the universe first began to exist, or 13.8 billion years ago. A flash of light traveling from one end of a room to the other wall takes ten billion attoseconds; this is a more concrete example. Long believed to be the upper limit for the amount of light that could be produced in a femtosecond. To observe activities occurring on the astonishingly short timelines of electrons, it was not enough to improve existing technology; something completely new was needed. The investigations that this year’s prizewinners carried out helped to establish the attosecond physics as a new field of study.
Shorter pulses with the help of high overtones
The vibrations in electrical and magnetic fields that make up light travel through a vacuum more quickly than any other type of wave. These have various wavelengths, which correspond to various colors. For instance, red light has a wavelength of 700 nanometers, or about a hundredth of a hair’s breadth, and it cycles at a rate of around 430 billion times every second. The length of a single period in the light wave, or the cycle where it swings up to a peak, down to a trough, and back to its starting position, can be thought of as the shortest conceivable pulse of light. The wavelengths employed in conventional laser systems in this situation are never able to get below a femtosecond. so in the 1980s this was regarded as a hard limit for the shortest possible bursts of light.
Any wave form can be created provided sufficient waves of the appropriate sizes, wavelengths, and amplitudes (distances between peaks and troughs) are utilized, as shown by the mathematics that explains waves. The secret behind attosecond pulses is that by combining more and shorter wavelengths, it is feasible to create shorter pulses. Light pulses that are brief enough to observe electron motion on an atomic scale must be combined from short waves with a variety of wavelengths.
More than simply a laser is required to add new wavelengths to light; the key to reaching the shortest time yet observed is a phenomena that develops when laser light passes through a gas. Overtones are waves that finish multiple full cycles for each cycle in the original wave as a result of the light’s interaction with the material’s atoms. The overtones that give a sound its own character can be compared to this in order to understand the differences between the identical note played on a guitar and a piano.
Using an infrared laser beam that passed through a noble gas, Anne L’Huillier and her colleagues at a French laboratory were able to create and show overtones in 1987. Infrared radiation compared to the shorter wavelength laser used in earlier research, produced more and stronger overtones. Numerous overtones with almost the same light intensity were seen in this experiment.
Throughout the 1990s, L’Huillier continued to investigate this effect in a number of studies, including at her new location, Lund University. Her findings helped theorize about this phenomena and laid the groundwork for the subsequent experimental discovery.
Escaping electrons create overtones
The electromagnetic vibrations that the laser light produces when it interacts with the gas’s atoms and enters it disrupt the electric field that holds the electrons around the atomic nucleus. This allows the electrons to leave the atoms. The electrical field of the light, however, is always vibrating, and when it changes direction, a free electron can race back to the nucleus of its atom. The electron collected a lot of extra energy from the electrical field of the laser light during its excursion, and in order to reattach to the nucleus, it must discharge this extra energy as a pulse of light. The overtones observed in the experiments are produced by these light pulses from the electrons.
The wavelength of light is related to its energy. The overtones’ energy is comparable to ultraviolet light, which has shorter wavelengths than light that can be seen with the naked eye. The overtones’ vibration will be neatly proportional to the wavelength of the first laser pulse because the energy comes from the vibrations of the laser light. Different light waves with a range of distinct wavelengths are produced when light interacts with a variety of different atoms.
Once present, these overtones start to interact with one another. When the peaks of the lightwaves coincide, the light is stronger; however, when the peak of one cycle coincides with the trough of another, the light is weaker. When the overtones line up just perfectly, a sequence of short-duration ultraviolet light pulses—each lasting a few hundred attoseconds—occurs. The underlying idea was understood by physicists in the 1990s, but it wasn’t until 2001 that the pulses were actually identified and tested.
A train-like sequence of consecutive light pulses was created and studied by Pierre Agostini and his research team in France. To determine if the overtones were in phase with one another, they employed a novel method in which they combined the “pulse train” with a delayed portion of the initial laser pulse. As a result of this approach, they were also able to measure how long each pulse in the train lasted—it was only 250 attoseconds.
Ferenc Krausz and his research team in Austria were developing a method that could choose a single pulse, similar to a carriage being decoupled from a train and shifted to a different track, at the same moment. The team used the 650 attosecond pulse they were able to isolate to track and examine the mechanism by which electrons were drawn away from their atoms.
These tests showed that attosecond pulses were both observable and measurable, and that they might be applied to new research.These brief light bursts can now be utilized to analyze the motions of electrons because the attosecond universe is now accessible. Currently, it is possible to create pulses with durations as low as a few dozen attoseconds, and this technology is continually improving.
Electrons’ movements have become accessible
With the aid of attosecond pulses, it is feasible to time how long it takes an electron to be pulled away from an atom and analyze how this time is influenced by how strongly the electron is attached to the atom’s nucleus. Previously, their location could only be determined as an average. Now, it is feasible to recreate how the distribution of electrons oscillates from side to side or place to place in molecules and materials.
Attosecond pulses can be used to examine a material’s interior workings and to distinguish between various events. These pulses have potential uses in fields ranging from electronics to medicine and have been used to investigate the intricate physics of atoms and molecules.
Attosecond pulses, for instance, can be used to push molecules, causing them to release a signal that can be measured. The signal from the molecules has a unique structure that functions as a kind of fingerprint that identifies the specific molecule, and potential uses for this include medical diagnostics.