Dr. Katalin Varjú, our Science Director, has been interviewed by



Physics graduates are in high demand, so they can expect competitive salaries. Yet, few young people choose this profession, which is not surprising for Dr. Katalin Varjú, Science Director of ELI ALPS Laser Research Institute, as the number of physics teachers is also rapidly decreasing, and there is no one to teach and motivate young people. With the Szeged-based laser centre, Hungary has established a world-class research facility and invested in the future. Yet, it will be years or decades before we learn whether the research results achieved here may lead to scientific breakthroughs.



Pierre Agostini, Ferenc Krausz and Anne L'Huillier were awarded the Nobel Prize in Physics in 2023 for their experimental methods for the generation of attosecond light pulses. ELI ALPS in Szeged was built on the basis of these discoveries. You were a student of Anne L'Huillier. How did you feel when this decision was announced?

- I was on my way to a conference in Budapest when my colleagues called me with the sensational news, and by the time I got to the event, the news had spread among the participants. As this is also my field of research and the word ‘attosecond’ is in the name of our institute, we too came into the spotlight. The assignment of the Nobel Prize is a long and thorough process; it is awarded for a specific result, not for lifetime achievement.  A precondition for the award is that the achievement must be useful after its discovery, as Nobel’s last will states that the prize should be  awarded to "those who have conferred the greatest benefit to humankind". Attoscience is a very exciting, very interesting field of research, but I was surprised that it was acknowledged with the Nobel Prize already in 2023. It may not have reached the stage of maturity where it would be generally known that a related application will make life easier for all of us. The members of the selection committee saw it differently, which I am incredibly pleased about. I am also proud to know these Nobel laureates personally, and to have shared research with them. It is still not easy to explain to lay people what I do, what attosecond science is about, but everyone knows that it has been recognized with the Nobel Prize. 

"Attosecond pulses are the product of light–matter interaction. They are primarily used to take snapshots of fast-moving processes or dynamic systems." 


The ELI programme can be associated with other Nobel Prizes too. Gérard Mourou and Donna Strickland were awarded the 2018 Nobel Prize in Physics for their work on phase-modulated amplification. In 1999, Ahmed Zewail was awarded the Nobel Prize in Chemistry for demonstrating that fast lasers can be used to observe the rearrangement of atoms within molecules. In other words, the Szeged-based laser centre is making use of several earlier scientific breakthroughs. 


Did this level of recognition of the discipline confirm that the decision taken years earlier about the construction of the laser centre had been a forward-looking one, or did the establishment of the institute came as a surprise only for lay people?

- Many people look at it this way, but I must admit that when the planning phase of the attosecond research facility started in 2011-12, practically only we, laser physicists, knew that it was going to be very important for the development of science. In the case of our country, this was a step forward, because if a country does not invest in basic research, it will not produce applied research results either. With the laser centre in Szeged, Hungary has established a world-class research facility, investing in the future. The foundations have been laid, and it will be decades before we can see whether the research results achieved here will lead to scientific breakthroughs. 


Did you manage to reach the goal of having all lasers operational by mid-2023?

- In September 2023, the capital investment project was completed, all the research equipment has been handed over, and everything is up and running. The technical parameters have changed slightly compared to the portfolio planned in 2011, which is no surprise to anyone in the field of research and development: ten years have passed, which means ten years of progress. Lasers and photonics applications are especially undergoing a very intensive phase of development. At the start of the project, we counted with five lasers and eleven target areas driven by them. Now, at the end of the project, we have eight individually developed lasers and four smaller lasers designed for experiments, with more than fifteen experimental setups. 

"We have successfully completed the capital investment project, all our lasers are working properly. This means that our research facilities are unique, world-class, and ready for research." 


The construction phase is now over, and the commissioning and upgrading of the equipment is in progress. Is it a quieter period for ELI ALPS? 

- Ideally, a research centre is not a tranquil place, but rather a place of constant bustle, development and change. We are currently working to make our experimental setups as stable as possible, to conduct as many successful experiments as possible and to serve more and more users. With the completion of the capital investment phase and the large project, the focus is shifting from administrative tasks to research. This is delighting for a researcher like me. 


The e-SYLOS accelerator chamber and user endstation installed in the MTA laboratory at ELI ALPS. 


In spring 2020, the experts in charge of coordinating the ELI project in Brussels submitted an application for the foundation of ELI ERIC (European Research Infrastructure Consortium), which was approved at the EU’s headquarters in spring 2021. Why was this step necessary? What is the role of ELI ERIC?

- ELI is a European project involving the establishment of three research institutes (in Szeged, Prague and Bucharest). A huge problem in experimental science is that technologies are constantly evolving, meaning that what was at the cutting edge of the world this year may be obsolete in a few years' time. I would say that the most important task of ELI ERIC is to support operation and development. It would help a lot if the European countries, which have been less active so far, would support this concept financially. After all, we serve the whole of Europe: our world-class laboratories attract users mainly from Europe, and to a smaller extent from further afield. It is in the continent’s interest to operate and develop the research centre, and to keep it at the forefront of the field. 


Due to the coronavirus outbreak, supply chains were disrupted, causing extreme delays in your procurements. It was very difficult to purchase quality goods at affordable prices in a short time. The delivery times for optical components, which could be procured in two to three months before the pandemic and the Russian-Ukrainian war, increased to 10-11 months. Has the world gone back to normal since then?

- The situation has improved, but we are not back to business as usual. Lasers include very expensive components, and manufacturers do not keep everything in stock. Last summer, a mirror stopped working and we waited two and a half months for a replacement. Another example: in the procurement procedure we have just launched, we intend to buy laser crystals of different sizes. Some crystals will be delivered with a two-year lead time. These crystals are grown slowly under special conditions with incredible precision to avoid the formation of bubbles and other structural defects. These crystals are so expensive that companies do not stockpile them. They produce them when they are needed, as they are grown specifically for particular lasers. 


ELI ALPS is a user facility, which means that it announces user calls for research proposals requiring the use of its lasers. The fourth user call was announced at the end of March. What has been the experience so far? Which researchers and research topics does the research opportunity in Szeged appeal to?

- We announce user calls twice a year. Anyone, anywhere in the world can apply to run experiments. Researcher may come from universities or research institutes, but it is not a requirement to have an academic background. The proposal must include a scientific plan, which is evaluated by a panel of internationally recognized researchers. Of course, the evaluators also consider feasibility – an idea may be brilliant, but if it is not feasible, there is nothing to talk about. We welcome proposals not only from laser physicists, but also from particle physicists, chemists, materials scientists, radiobiologists, plasma physicists, or researchers studying extreme high energy interactions. So, the range is sufficiently wide. Companies also apply sometimes. We had a Swiss applicant who submitted a proposal to test a new type of detector. 


The 3.2 micrometre (relatively long) wavelength of the MIR (Mid-Infrared) laser allows for special experiments. For example, it enables the generation of high photon energy and high electron energy for nuclear magnetic spectroscopy or light-induced electron diffraction (LIED). It is very well suited for the excitation of semiconductor crystals or for the investigation of solid materials.


Do users have to pay for the measurements?

- No, if a researcher comes to us through an open user call, i.e. a scientific panel confirms that their proposal has high scientific merit and they agree to make the results of their measurements public after three years. In fact, sometimes we spend money on such type of research: if there is a need for a specific instrument, we agree to purchase it within certain limits. On the other hand, if someone wants to keep the measurement results as a trade secret, we do charge a fee for the measurements. The EU expects all publicly funded measurement results to be made public. 


Where do your researchers and users come from?

- With the exception of Australia, all continents have been represented in Szeged. Our most distant users came from South Korea – they wanted to test their new laser diagnostic concept at a different wavelength. Our longest-staying user, an American researcher on a Fulbright scholarship, spent four months with us.


 ELI ALPS related scientific results get published one after the other. How can you help this process? What conditions are needed to ensure that relevant research results are achieved in Szeged?

- As I mentioned earlier, one of the basic conditions is the continuous provision of the necessary financial support for the operation and development of the equipment. Equally important is the availability of researchers and specialists who operate the equipment, who are far fewer in number than is desirable. Members of the younger generations that have grown up in the recent decades have not shown sufficient interest in physics and engineering. This is true not only for our region, but for Europe as a whole. 

"The biggest problem with laser-based research infrastructures is that we can't find enough young people who want to work in laser physics."


 Over the past decades, the laser industry has grown dynamically around the world, and specialists are in short supply. We would need many more people with photonics skills. I’m told by people I know at the University of Technology that companies are offering jobs to engineering/physics students as soon as they successfully complete their third semester. Physics graduates are in high demand, so they can expect competitive salaries. Yet, few young people choose this profession, which is not surprising, as the number of students enrolling into the physics teacher training programme is also rapidly decreasing. If there is no one to raise young people’s interest in this subject, then we should not be surprised that only few are studying in this direction. 


Your interactive visitor centre opened in November 2021. I've heard several times that people in Szeged are still a bit apprehensive about the institution, wondering what experiments are going on within its walls. You are trying to alleviate these reservations with science-promoting events such as the Day of Light, Researchers’ Night, Physics Day. Have you managed to reach the lay public?

- To my great pleasure, a lot of people come to these events, which means that they are interested in what’s going on here. And for those who are interested, we give the opportunity to have an insight. We use these events to promote physics and careers in research, and to guide young people in this direction to ensure a fresh supply of researchers. Physics is not the easiest, most accessible degree, but if you are not afraid to think, you can get a very useful qualification! I think physics is very exciting and interesting, and being a physicist is great. 

"Physics teaches you how to solve problems and understand the correlations between processes."


Physicists research and interpret what is happening around them, and understanding is followed by the desire to take control. This is very useful, valuable knowledge that one must work for (and that is worth working for). 


The institution is well known in Szeged, but what does the wider national and international public know about it?

- By today, we have become known in the field. For years, our researchers and users have been presenting their results at conferences, which is the most effective way to inform the professional community. European research centres are constantly initiating joint projects, encouraged by the Horizon Europe programme, and ELI is involved at an increasing rate. We also have partners in the USA, where the construction of research centres that are similar to ELI has taken off in the last few years, so we have regular exchanges with them. In addition, a lot depends on personal contacts. Ten years ago, two Indian physicists started working for us, and since then nearly a dozen Indian scientists have joined the research centre. To attract a researcher from so far away, it helps if you know someone who has worked at the institute and can give you a reference. This is why people in India know about the existence of ELI ALPS. French, German, American colleagues have also visited us. However, I must admit that it is not easy to bring here someone from Western Europe. The research conditions are world-class, but the salaries are still below Western standards. We also have the disadvantage that the institute is only a few years old. Long-established research institutions with decades of traditions offer a predictable career path. We are still in the development phase, so we can only guess what a professional can expect. Last year, nearly eighty researchers of ours published thirty-four scientific papers, which is not a lot in absolute terms, but it is encouraging given the steady process of commissioning and the upward trend. We know that we have not yet reached the level that would make it easier to attract researchers, but we are moving in that direction. And I would like to say that I am immensely proud of every single paper we produce.