It is a prize I was expecting and it is fair, although there have to be three winners and someone can always be left out. It involves devising new ways of measuring that go further, and every time a new window opens, knowledge opens. Being able to follow the movement of electrons in units of attoseconds, which is one millionth of a billionth, is a feat. And extending it to solids as well. [In terms of possible applications] If we are able to follow the movement of electrons in such small times, we may be able to direct them more precisely in therapies.

The Swedish academy awarded this prize for attosecond research. This is a young scientific field, born in the present century. In 2001, F. Krausz generated in his laboratory in Vienna the first light pulse with a duration on the attosecond time scale (1 attosecond is one trillionth of a second), thus making it possible, for the first time, to capture time-lapse images of the motion of electrons in matter. It was the crowning achievement of very rapid advances in laser technology, with significant contributions from P. Agostini and A. L'Huillier.   

This technology has made it possible to obtain experimental measurements that only a few decades ago seemed unattainable, from being able to quantify the time differences in the emission of electrons from different levels of the same atom, to visualising in real time the redistribution of charges in biological molecules. Attosecond pulses have been able to access the most fundamental mechanisms governing the formation and breaking of chemical bonds, i.e. to get to the heart of physics and chemistry at its most fundamental level. And it looks like this may just be the beginning of attochemistry, attobiology and, who knows, atto-medicine. Applications are on the way. 

Beyond the joy of being able to congratulate one of our collaborators, A. L'Huillier, and other colleagues in our scientific community, for us, working in attosecond science, this Nobel Prize is an incentive and a motivating element, as it recognises a relatively young science. The great applications of this technology are still to come, and such recognition always serves as an incentive. Hopefully, it will boost the already incipient applications in other areas such as chemistry and even biology.

I am delighted to see the pioneering work of Pierre Agostini, Ferenc Krausz and Anne L'Huillier recognised with the Nobel Prize in Physics. Their experimental breakthroughs, which enabled the generation of trains of laser pulses with durations on the attosecond scale, have allowed the study of processes on time scales previously impossible to reach, making an extraordinary contribution to advancing our understanding of matter.   

This is yet another of the many well-deserved Nobel Prizes in photonics in recent decades, confirming lasers as the definitive enabling technology of the second half of the 20th century and so far in the 21st century, capable of opening windows to the exploration of the universe through the detection of gravitational waves, as well as allowing the most precise measurements of the smallest magnitudes or objects or exploring the fastest events in nature.

I am very excited that the Nobel Prize 2023 has been awarded to this breakthrough in basic research and that it has been awarded to Pierre Agostini, Frenec Krausz and Anne L'Huillier. I am particularly familiar with the careers of Anne L'Huillier and Frenec Krausz, who was recently awarded the Wolf Prize in Physics 2022 and the BBVA Foundation Frontier of Knowledge 2023 prize.  

Anne L'Huillier, a theoretician by training, was a pioneer in demonstrating that the generation of very high harmonics is possible, allowing pulses to be produced with a time as short as an attosecond (one part in 10^18 of a second). Frenec Krausz was the first to produce these ultra-short pulses in a controlled manner in his laboratory at the University of Vienna, decades later, in 2001.  

These discoveries have made it possible to 'photograph' the movement of electrons in atoms and molecules, allowing us to understand their dynamics and how, for example, their photoionisation occurs. Today, real-time movies of these processes can be made.

Attosecond Pulses of light are a revolutionary tool for basic and applied science since they give us for the first time a camera that is fast enough to acquire crisp images of how and where electrons move. This is important since the motion of electrons determines literally everything, from how a chemical reaction happens, how we metabolise, or how materials and sensors work. The three winners represent this extremely fast-growing new interdisciplinary field of science very well to which many people have been contributing.

People always think that the shortest time is the time from when the traffic lights turn green to when the car behind you beeps. Not so! This year's Nobel Prize has been awarded to three scientists who have pioneered lasers with the shortest pulses, the attoseconds. 

These pulses can now be obtained in a variety of ways, but all three pioneered them by generating harmonics. Starting from an infrared laser, they obtained multiples of its frequency (what we call harmonics). The three laureates have pioneered these techniques in order to obtain from a series of harmonics with well-controlled phases a pulse of very short duration, breaking the barrier of a few femtoseconds and going down to the next scale, the attosecond. 

The development of femtosecond lasers was key to the study of chemical reactions, which led to the Nobel Prize in Chemistry being awarded to Ahmed Zewail for the invention of femtochemistry.  

Now, these three laureates have taken it a step further. At the attosecond scale, ions have no time to move because of their mass. However, electrons, which are much lighter, move precisely on this time scale. Thinking of an atom as a planetary system (with the caveats imposed by quantum physics) the electron orbits on this time scale, hence its interest. 

In Europe, there are two major facilities dedicated to attoseconds. One is ELI-ALPS in Szeged, Hungary, based on the techniques developed by these three pioneers. The other is Eu-XFEL in Hamburg, Germany, where they have developed an alternative technique based on electrons accelerated to enormous energy. Both are ESFRI facilities. 

Attoseconds are now a reality, I would not say an everyday reality, but one that is accessible to the scientific community, and this has been made possible by the three laureates and their pioneering work.

The award of the Nobel Prize in Physics 2023 is undoubtedly excellent news and a source of joy for the national groups working in the field of attophysics, several of which we collaborate with some of those who have received the prize. Lasers are a special light source because of their coherence, i.e. because they emit light in the form of waves with very regular characteristics, light whose structure can be modified at will in laboratories. The laureates developed fundamental contributions that enabled this type of light to be used to control the motion of electrons on scales as short as a few tens of trillionths of a second, technically called the attosecond scale.  
Attosecond technology provides new tools for scientific research, such as flashes of light so brief that we can resolve the motion of electrons in atoms, x-ray laser sources that allow us to probe nanometre structures, and experimental designs that allow us to measure how long processes such as ionisation take - durations so short that they have never been measured before. The three laureates are not only pioneers in this type of technique, but have also developed solid scientific careers, extended over time, and have made an outstanding contribution to the consolidation of atoscience as a new discipline in physics.

This is fantastic news and a long-awaited and long-awaited recognition by the scientific community of optics and ultrafast lasers. Thanks to attophysics, we can now observe processes occurring in nature in times as short as trillionths of a second, something that until a few years ago we could only fantasise about. It is in such a brief world that the movement of electrons within atoms and molecules takes place, and developing a "camera" that allows us to observe them is the first step towards understanding the most fundamental processes in nature.  

Once understood, we can go a step further and manipulate them, for example to create new materials to meet the challenges facing our society. The experimental work of Professors L'Huillier, Agostini and Krausz has been instrumental in the development of such a "photo camera", formed by laser pulses with durations of attoseconds (1 attosecond is 0.000000000000000001 second!). Its creation and characterisation was far from easy. The process that has succeeded in generating these pulses is called high-order harmonic generation, a highly non-linear process that combines several branches of physics: intense laser optics, quantum physics and classical electrodynamics. Although the first experiments were developed in the late 1980s, today we are still refining and understanding the technique of generating these very short pulses.

It is a long-awaited award that recognises a crucial breakthrough in the development of lasers as an interdisciplinary and enabling technology. This type of laser, consisting of attosecond pulses of light, makes it possible to study the nature of ultrafast phenomena, such as the movement of electrons in atoms and molecules. It will undoubtedly also play an essential role as a tool for manipulating and controlling matter at such small scales, all using light!

Once again, the Nobel Prize in Physics recognises excellent experimental work. On this occasion, recognition is given to work where the manipulation of light allows us to enter the world of electrons, where optics and atomic physics go hand in hand. In the late 1980s, lasers with ultra-short femtosecond pulses (1 fs=10^-15 s) were sufficiently developed so that the start of the electromagnetic field could excite electrons bound at extremely high levels to a situation close to ionisation and that the end of the field would then bring the electron sharply closer to the nucleus. On this journey the electron releases energy in the form of highly energetic photons, in the form of coherent electromagnetic fields of very short wavelength. This is called high harmonic generation, HHG (High Harmonic Generation). Assembling these fields properly in time, the total field has a duration of attoseconds (1 as=10^-18 s).

These are the fastest physical events that man can make, measure and use to follow the electronic dynamics in atoms and molecules. And if you can see what an electron does, its transition between orbitals in real time, it is clear that this is a new period for science. This is attoscience, one of the key disciplines of the 21st century.

This is basic science, but what are its applications? We have 80 years to go before the end of the century.

The 2023 Nobel Prize in Physics, along with previous years such as 2018, once again highlights the importance of optics, lasers and photonics from a scientific and technological point of view. The work of the award winners laid the foundations of attophysics. Optical tools are essential in a multitude of applications, allowing interaction with materials with high spatial resolution in applications such as microscopy, biomedicine or materials processing, among many others.

Ultra-short and ultra-intense laser technology is unique for several reasons. On the one hand, it allows a temporal resolution unmatched by other techniques, thanks to the production of ultra-short pulses on an attosecond scale (1 attosecond = 10^-18 seconds, i.e. 1/1000000000000000000 seconds). This is where one of the keys to this Nobel Prize lies, thanks to the discovery, understanding and management of the process of generating high order harmonics. The electromagnetic fields that propagate in visible light oscillate on slightly longer time scales, but the process studied makes it possible to generate pulsed lasers in other spectral ranges (extreme ultraviolet and X-rays), in which the light oscillates even faster and allows shorter pulses to be obtained. On the other hand, these light sources are able to interact with the structure of matter at deeper levels, which has made it possible to study electronic and even nuclear dynamics on ultrafast scales.

In recent years, I have interacted scientifically with Professor Anne L'Huillier through the collaboration between the University of Salamanca, the University of Porto, the University of Lund and the company Sphere Ultrafast Photonics (spin-off of which she is co-founder), with developments and publications related to the dispersion scan technique used to temporarily measure the laser pulses that produce the harmonic generation process.

The Nobel Prize in Physics awarded to Pierre Agostini, Ferenc Krausz and Anne L'Huillier is a well-deserved recognition for their pioneering work in the generation of extremely short pulses of light, known as attoseconds. These scientists have revolutionised our understanding of how electrons move in matter, allowing us to 'photograph' the dynamics of electrons in action. 

Imagine being able to capture in slow motion the flight of an insect. Similarly, these laureates have developed technology that allows us to observe how electrons behave on incredibly small timescales, on the order of attoseconds, which are a billion times shorter than a second. This is essential for understanding fundamental processes in chemistry, physics and materials, and could have revolutionary applications in areas such as quantum electronics and nanotechnology. In short, their work has given us a new window to explore the subatomic world and promises significant advances in science and technology in the future.