In October 2023, the Nobel Prize for Physics was awarded for ‘experimental methods that generate attosecond pulses of light for the study of electron dynamics in matter’. This burgeoning field of research and its practical application has benefitted greatly from the support of a series of COST Actions including the Action Attosecond Chemistry (AttoChem).

The 2023 prize was jointly awarded to Pierre Agostini of Ohio State University, Ferenc Krausz of the Max Planck Institute of Quantum Optics in Munich, and Anne L’Huillier of Lund University in Sweden, who is an active member of AttoChem.

COST is proud to have worked with all three Nobel laureates in more than one COST Actions over the years that have helped build a thriving European research community in this important field.

Attoseconds

An attosecond is one billionth of a billionth of a second. This is an incredibly short time: a flash of light takes around ten billion attoseconds to cross a room. But in the world of electrons, it is the time scale in which they move and change energy. To probe the dynamics of this world you need a tool that works on that same time scale of between one and a few hundred attoseconds.

For many years it was thought that such a tool would not be accessible. However, the work of the three Nobel laureates showed that through a clever combination of the overtones generated by the interaction of lasers passing through a gas, light pulses of attosecond duration could be generated.

The AttoChem COST Action coordinates experimental and theoretical efforts to exploit the enormous potential of attosecond techniques in chemistry. The results of this Action can have a significant impact on several areas of chemistry, including photovoltaics, radiation damage, catalysis, photochemistry and structure determination.

A European prize

“I think this type of Action is very important,” says Professor Anne L’Huillier. “I am strongly in favour of European networking, which is facilitated by this type of Action.”

“There have been previous COST Actions in this field that have played a big role,” she continues. “This field has been supported by COST Actions and before that the European Science Foundation and this has been important to help young researchers, to support collaborations, and to ensure that people meet regularly. I am convinced this is one of the reasons that this 2023 Nobel Prize is very much a European prize. Europe is very strong in this important field and has been helped very much by COST Actions amongst other European Union activities.”

In particular, Anne appreciates COST’s short-term scientific mission funding, which enables younger researchers to travel for short visits to other laboratories, as very valuable to build and sustain the science community, exchange ideas and initiate collaborations.

Anne also believes that initiatives such as COST Actions are helping to close the gender gap in science and physics in particular. Only five women, including Anne, have ever been awarded the Nobel Prize in Physics since its inauguration in 1901.

“Only two women were awarded the Nobel Prize in Physics over its first 120 years or so,” comments Anne. “Now there have been three more within five years, which is better, but it could be much better!”

In her Nobel Prize acceptance speech, Anne highlighted the gender gap issue and said that she hoped her award would help inspire more women to be involved in physics. “The trend is that the gender gap is going to become less and less. But it takes time,” she says.

“There are many women involved in the AttoChem Action,” continues Anne. “And there are really many incredibly good women in the field. I cannot say why but hopefully maybe this is a field in physics where the gender gap is not so big and possibly again this type of Action and networking may help. COST Actions help ensure that young women scientists are visible and that they feel invited.”

And Anne sees the research field rapidly expanding. “The AttoChem Action covers one big field in the research area – looking at the dynamics at the beginning of molecular processes – but the area is actually exploding into many different directions,” she says. “You have chemistry, condensed matter, quantum, industrial applications, imaging and many more.”

Close collaboration

Professor Fernando Martin of the Universidad Autónoma de Madrid is Chair of the AttoChem Action and has been a close collaborator with Anne over the years and a co-author with her on several scientific papers.

Fernando is keen to highlight Anne’s involvement in AttoChem. “Anne has actively participated in the Action,” he says. “She has given plenary talks in our workshops and taught at our training school in Sicily that attracted over 100 participants – mainly young researchers.”

He agrees that the 2023 Prize is a very European Nobel Prize. “It is 100% European. The technology that allows one to generate attosecond pulses was developed in Europe in the late 80s and the 90s and was practically finished by the beginning of this millennium,” he explains. “So, then the question was how can we use this to best effect? What are the possible applications? And this is where COST appears. Of course, it did not start with Attochem. There were other COST Actions before, but their focus was not exclusively on attosecond chemistry but, for example, on ultra-fast phenomena, atomic systems and materials.”

“The very first application of the technology to molecules, related to chemistry, was a paper published in Nature in 2010,” recalls Fernando. “The experiment was in Milan and Anne Hullier was involved, as was I.”

A Nobel Symposium in August 2023 gathered together thirty prominent scientists in the field to celebrate the three Prize winners and to review progress in the field. “It was an amazing thing that eight of the authors of that 2010 paper attended the symposium,” he continues. “That work and the 2010 paper opened the possibilities – showing explicitly that this technology could be used to follow the electronic motion of molecules and manipulate this electronic motion to do some exotic chemistry. This was the starting point of the AttoChem idea.”

The Nobel symposium included six sessions: half dedicated to showing how attosecond pulses were developed and half possible on ongoing applications. “Attochem was the official organizer of one of the application sessions,” says Fernando proudly. “Which shows you how significant the COST Action has been.”

The AttoChem Action ended in April 2024, but new COST Actions in the field are being considered and one has recently started – appropriately entitled NEXT  – which focuses on the use of free electron lasers – a new avenue of exploration for this prizewinning research area.

Additional information

Discover the AttoChem videos:

Read more about COST Action Attosecond Chemistry (AttoChem)

Read more about the 2023 Nobel Prize in Physics

Read more about COST Action An international network for Non-linear Extreme Ultraviolet to hard X-ray techniques (NEXT)