The 2023 Nobel Prize in Physics puts the spotlight on the Centre of Intense Lasers and Applications

One was supervised by Pierre Agostini during his PhD and carried out his postdoctoral studies with Anne L'Huillier, while the other was Anne L'Huillier's PhD student and a contributor to one of Pierre Agostini's major research projects. Both explain that they were extremely moved on Tuesday 3^rd October when the Nobel Prize for Physics 2023 was announced. It's hard to imagine the opposite, given the ties that bind Éric Mevel, professor at the University of Bordeaux and current director of the Centre of Intense Lasers and Applications (CELIA, a CNRS, CEA and University of Bordeaux unit) and Philippe Balcou, CNRS research director and former director of the same laboratory, to two of the 2023 Nobel Prize winners.

And they aren't the only ones. Dominique Descamps, a CEA researcher seconded to CELIA and head of the femtosecond optics and lasers group within the unit, was also a post-doctoral fellow at the University of Lund (Sweden) with Anne L'Huillier. Similarly, Fabrice Catoire, CNRS research fellow and head of the XUV harmonics, ultra-short processes and applications group at CELIA, was more recently a post-doctoral fellow at Ohio State University (USA) with Pierre Agostini, not to mention the countless collaborations and partnerships for over 20 years now between CELIA and the research unit of the Nobel Prize-winning French-Swedish physicist, as well as the small stories within the larger story of fundamental physics. As it happens, Philippe Balcou remembers being present when Anne L'Huillier met the researcher Claes-Göran Wahlström, who later became her husband and led to her departure for the southernmost city in Sweden.

Award-winning pioneering experiments

The Bordeaux researcher was also totally stunned when following the Nobel announcement live, not by the almost expected distinction of his friend Anne L'Huillier, who had already received the prestigious Wolf Prize in Physics in 2022, alongside Ferenc Krausz (from the Max Planck Institute for Quantum Optics). But by that of CEA researcher Pierre Agostini, now in the United States. "Everyone was expecting the same winners as the Wolf Prize." So the emotion was twofold. Philippe Balcou explains that in the 1990s and early 2000s, Pierre Agostini, although a CEA researcher, carried out most of his work in his research unit, the Laboratoire d'Optique Appliquée (LOA), and that the two of them had combined their efforts and their equipment to carry out the experiment devised by Pierre Agostini and Harm Muller for which he is being honoured today.

Éric Mevel speaks of a scientist of exceptional calibre, referring to the person who supervised his postdoctorate. "She has intuitions, and she sets out to test them, even if she's the only one who believes in them". And sometimes even a little against her superiors, who didn't really believe in them," concedes Philippe Balcou. "Anne L'Huillier has given rise to a new field of research, something that few researchers can claim, while always remaining involved in teaching," continues the current director of CELIA. Moreover, the anecdote shared in the media that the physicist returned to class after the announcement of her prize in order to finish teaching did not surprise either of the two Bordeaux scientists.

It is therefore the field of attosecond fundamental physics (one billionth of a billionth of a second) that has been rewarded by this Nobel Prize, in particular the founding experiments in this field. The two Nobel laureates carried out almost the same experiment: subjecting a gas to a laser, then studying what happens at the level of matter to understand the physical phenomena of the infinitely small. And where Pierre Agostini characterised photons by measuring electrons, Anne L'Huillier tracked down electrons by measuring photons.

Five attosecond pulses of light

The HXUV team operates 5 attosecond light lines open to transnational access on a European scale within the framework of the Laserlab-Europe infrastructure, to which Anne L'Huillier's laboratory also belongs. Today, CELIA and the Laboratoire intéractions, dynamiques et lasers (LIDYL) at Paris Saclay are the two French laboratories boasting several light lines and substantial attosecond teams. This dynamic of French excellence, honored by this award, is complemented by other laboratories that are major players in this long-standing field of physics, such as the aforementioned LOA, the Laboratory of the Physics of the two Infinities Irène Joliot-Curie (IJCLab) in Paris, the Strasbourg Institute of Materials Physics and Chemistry (IPCMS) and the Institute for Light and Matter (ILM) in Lyon.

Over 40 publications have been published associating CELIA members and Anne L'Huillier, including a dozen on inter-institute partnerships, the most recent of which was published in 2023, and around twenty have been published with Pierre Agostini.

The combination of simplicity and determination, which characterizes both Anne L'Huillier and Pierre Agostini, should not change too much despite this international recognition, explain the two Bordeaux-based researchers, who describe two impressive personalities in their field who have always managed to remain modest. The laboratory also hopes to soon welcome the Franco-Swedish physicist, who is one of the 10 CNRS "ambassador-fellows" in 2023. In this respect, the Centre of Intense Lasers and Applications is one of the 3 laboratories (along with LIDYL and IML mentioned above) that will be visited to strengthen scientific ties.

Image caption: 
The movements of electrons within atoms and molecules are so rapid that they are measured in attoseconds. An attosecond is to a second what a second is to the birth of the universe.