We offer limitless opportunities to young people – Interview with Nobel Prize winner Ferenc Krausz

From your first statements we know that the Nobel Prize news came as a surprise, but how much did the attosecond physics community expect such recognition?

The Nobel Foundation organised a Nobel symposium on this subject a few weeks ago, which usually sends a message to the community that the field has reached, so to speak, the stimulus threshold for the Nobel Prize Committee for Physics. But the interesting thing is that this interest was regarded as an almost certain indication that the prize would not be awarded in this field this year – the statistical average is that it takes several years before this happens. So we did not expect it, especially as the symposium was held at the end of August and, presumably, with just over a month to go before the announcement, the committee’s work would be well advanced.

Ferenc Krausz Photo: Max Planck Kvantumoptikai Intézet/Daniel Gerst

The surprise must have been even bigger then, as it was for the public, in that you donated a significant part of the prize money to a charitable foundation, Science4People. As I saw on the foundation’s website, it is an initiative of the attosecond community. What motivated you to do this?

In Germany the law says you need at least seven people to set up an association, so I had to go around the colleagues and, as their boss, tell them what it was about and ask them if they could get involved. The colleagues who finally joined did so with great joy and motivation after our conversation. It all started from the fact that I have been visiting Hungary regularly for quite some time now, thanks to the CMF project (Centre for Molecular Fingerprinting). And in Budapest the conflict in Ukraine is much closer, at least as I experienced it, it was very different there than in Germany – especially in the early days, when tens of thousands of refugees were streaming in from Ukraine every day. The news reports and images really got to me, and I wondered what I personally could do about it. I first thought I might go to the border to help receive refugees, but then I saw that my compatriots were doing a wonderful job. It occurred to me that perhaps I could do more through my network of contacts, and so I came up with the idea of launching such an initiative in which I would try to reach out to the scientific community that I know to ask them for donations. Not only donations of money, but also electronic devices, computers, laptops, which we keep receiving and then forwarding, and which our friends in Transcarpathia can use very well in various schools and educational institutions. I have been in contact with aid organisations there, one of which is called Tabula Rasa. This organisation focuses on supporting young people, and in close cooperation with them we are launching aid programmes specifically focused on younger children. The most recent is our SKOLA+ programme, which was launched just last week: we are recruiting teachers, primary school and secondary school teachers, to do tutoring and are paying them from our project. They teach needy refugee or local children – both Ukrainian and Hungarian, in both Ukrainian- and Hungarian-language schools. We place great emphasis on ensuring that this is not presented in a way that supports only the Hungarian minority specifically, but all those in need because of the war in general. I think that if we do it this way, and if it takes on visible dimensions sooner or later, it could even have signalling value at a political level. I have donated the amounts of two of my most recent prizes, last year’s Wolf Prize and this year’s Frontiers of Knowledge Prize, the former in full and the latter in considerable part, to the Foundation, and I would like to do the same for the Nobel Prize.

Reading the press material for the Nobel Prize, it would seem as if the three prizewinners’ efforts are interdependent elements of a story. What does it all look like from the point of view of the researcher?

To be honest, I haven’t had time to read the Nobel Prize Committee’s publications, but it is certainly true that the research activities of the laureates were built on each other without any concrete collaboration amongst any of them. That’s the beauty of science: we can benefit from each other’s work without needing direct collaboration. Anne L’Huillier’s research in the 1980s had already led to the generation of high-order harmonics. Our work is also largely based on this discovery, since we exploited this high-order harmonic generation process to ultimately produce attosecond light pulses. There were already significant Hungarian players in the field in the early 1990s: Csaba Tóth and Győző Farkas were among the first to predict that high-order harmonics could produce attosecond light pulses. However, it was the theoretical work of Paul Corkum that contributed most to the start of conscious research into the generation and measurement of attosecond light pulses. Experimental implementation was delayed until 2001. Pierre Agostini’s group generated and measured attosecond pulse trains, where an attosecond pulse was received every half-period of the generating light. At almost the same time, we published experimental evidence that an attosecond ultraviolet pulse isolated from a laser pulse consisting of a single oscillation cycle could be generated and measured. The first attosecond flashes of light, which were discovered at the Vienna University of Technology, were 650 attoseconds in duration.

These results are more than two decades old. Where have we been since then? Have we managed to go below 650 attoseconds?

A few years later, at the Max Planck Institute for Quantum Optics in Garching, we succeeded in producing pulses of 80 attoseconds, which even attracted the attention of Guinness, and were awarded a certificate. Since then, this record has fallen and migrated to America, where it is now around 50 attoseconds, which is not a problem for us here, because it means that we are not alone in this field, which is basically a good thing.

There are two research centres in Hungary dealing with attosecond physics: the ELI-ALPS Laser Research Institute in Szeged and the Centre for Molecular Fingerprinting, which you head. Have there been any practical applications?

ELI-ALPS is in fact a laser centre with attosecond physics at its absolute heart, as the acronym in the name Attosecond Light Pulse Source suggests. Of the three extreme light infrastructures (ELIs) – Bucharest, Prague and Szeged – Szeged was built specifically to provide an infrastructure for researchers from all over Europe, and ideally the world, who are interested in attosecond physics to come and, hopefully, use this equipment to carry out attosecond physics experiments. This prize is also a political signal in that it was perhaps not such a bad decision to set up this centre – it is a technology with a future and a basis for further important discoveries.

Can you tell us something about the work of the Centre for Molecular Fingerprinting?

We have had very encouraging results in the field of medical applications. We have recently looked at eight different types of cancer using molecular fingerprinting, and all eight are sensitive to some degree. But we also have a collaboration with Professor Béla Merkely, where we took a trip for the first time into the field of coronary heart disease. The first measurements indicate that the method is also sensitive to this disease. In the meantime, we also learned that it is sensitive to diabetes and even prediabetes, a condition that precedes it. These findings have encouraged us in Hungary to take a bigger step forward and not only start looking at individual diseases, whether or not the method is sensitive to them, but also to try to answer the question of whether the method could be used as a pillar of a broad health promotion programme, in fact, to monitor health status. This would involve taking regular blood samples and using molecular fingerprints measured by infrared light pulses to determine the range in which this highly informative signal should be present in a healthy person. We could then monitor continuously, tracking when it moves out of this personalised reference normal range, and then we would have to find evidence that when it does, it is a sign of some chronic disease. Obtaining conclusive evidence is a long process (6-8 more years). We are grateful to the Hungarian government for its ability and willingness to support such a long-term programme, despite the difficult economic situation, and for enabling us to lay the foundations for future preventive medicine. A world first in Hungary.

The Nobel Prize proves that this is an area of science worth paying attention to. But what would you say to a young person, a high school student or a BSc physics student about why they should choose this path?

This is a field of research that promises a huge variety of opportunities. It also provides the opportunity to those who prefer to work at the computer and want to develop their skills and use their knowledge in this area. Data science is a very important basis for this work – artificial intelligence and machine learning play a very important role in this field. Molecular fingerprinting research could also be attractive for those interested in life sciences. And lastly, we welcome those who prefer to work with technological equipment in the lab, because the equipment we use requires the highest possible quality electronics, optics and laser technology so that these measurements can be taken with the necessary accuracy and reliability. We offer young people limitless opportunities for development. We warmly welcome them!