“We have opened a door to a new world,” said Hungarian-Austrian physicist Ferenc Krausz about the development of attosecond physics, for which he will receive the Nobel Prize in Physics on Sunday. He wants to “really achieve this with more successes and hopefully breakthroughs,” as he told APA in Stockholm. He also sees the award as a “mandate” to focus primarily on the medical applications of this measurement technology in the future.
Question: How have things been for you in the last two months since receiving the award?
Ferenc Krausz: There were many questions from the media, which is very honorable and gave me the opportunity to inform the public about our research. I think this is important not only for our group, but also for the entire field, and perhaps for science in general. This gives you the opportunity to show the public what good what we do can be.
Question: Yesterday, Wednesday, this year’s Nobel Prize winners donated a personal item to the Nobel Prize Museum in Stockholm – what will be on display there in the future?
Krausz: We plan something bigger. We want to reassemble the system with which we detected the first attosecond pulses in the underground laboratory at the Vienna University of Technology in 2001. I offered this to the Nobel Museum and warned them that it would weigh a total of 50 kilograms.
Question: Is this the vacuum chamber that was called the “Suck Me Chamber” back then?
Krausz: Yes, that’s the vacuum chamber with all the instruments, some of which still need to be looked for. The nickname came from the fact that the vacuum pump had to make a lot of effort because the chamber leaked everywhere and even today you can see traces of this, like the glue that was used to try to close where it whistled. In this aspect, the space deserves the name “museum piece” and that is where it goes now.
Question: How does it feel to be part of this ‘Scientific Hall of Fame’?
Krausz: This cannot be described in words. When you see Erwin Schrödinger’s certificate in the Nobel Museum, for example, it’s difficult to process it. I will probably need a lot of time for this. In any case, I feel extremely humbled and see a task for the future: that a lot of effort still needs to be made to really conquer it with more successes and, hopefully, breakthroughs. We have opened a door to a new world with the development of these tools, but there is still much more that can be done – and now that we have received this recognition. And we will try to accept this request.
Question: You first generated individual attosecond light pulses in 2001, at that time lasting 650 attoseconds. Is the aim to shorten this duration even further and what is the current record?
Krausz: At the Max Planck Institute, we even entered the Guinness Book of Records with 80 attoseconds. But we are no longer record holders, which is pleasant because we are not alone and there are many groups working in this area. The record is now under 50 attoseconds, held by a group in the US.
Question: Does it make sense to strive for even shorter pulses of light – will there eventually be ketosecond pulses of light, i.e. pulses of light that are short in trillionths of a second?
Krausz: That certainly could be the case, although for ketoseconds you would have to use even shorter wave radiation. But I don’t think there’s a great need to do so at this point, because there’s a lot to search in the time window of a few tens to hundreds of attoseconds. This is the time interval where most electronic processes occur. All the questions that we derive from practical needs are linked to the movements of electrons that occur in this time interval.
Instead of becoming shorter, it’s now about expanding the full range of query techniques on what physical quantities can be measured with this quick snapshot. Unfortunately, we are not yet at the stage where we can take real photographs; for this we would need atomic resolution in the Ångström range, as is possible with X-ray diffraction. If you had very short-wave attosecond X-ray flashes, that would be theoretically conceivable – but we’re not there yet.
Question: If I understand correctly, will there be photos of electrons in the not-so-distant future?
Krausz: I think that will happen. It may take a few more years, but with the potential capability offered by X-ray free-electron lasers, it will be possible to combine atomic resolution in time with atomic resolution in space – and that’s what it’s all about.
Question: Nobel Prize winner in Chemistry, Elias James Corey, told Martin Karplus that he was lucky to have only received the Nobel Prize at the age of 83 because he had such a peaceful time for research. You now receive the award at the age of 61 – what else would you like to achieve or will you enjoy the freedom that a Nobel Prize offers and continue working in completely different areas?
Krausz: We have been researching in a completely different area for eight years: we have addressed a very important question in medicine and my focus is shifting more and more in this direction. I also consider this recognition (the Nobel Prize, note) as a mandate to focus myself and my group more or less completely on this new field of research from now on.
Question: What is it about?
Krausz: Our question is how can we fundamentally change the current healthcare system. Today we wait until people are sick before going to the doctor, which is often too late. It has long been known that preventive medicine is the future, but it fails because there is no cost-effective method that can provide sufficient information in a very simple way.
We wondered if attosecond physics could make a contribution and extract a lot of information from human blood. We are pursuing this goal with many encouraging successes: in eight different types of cancer, we have been able to demonstrate that we are able to measure the change in the molecular composition of blood caused by cancer using our attosecond measurement technology. Our goal is to take this detection technology to the point where a simple blood test is enough to protect people from serious illnesses.
Question: How long have you been?
Krausz: We are further along in terms of lung cancer, thanks to the greater number of lung cancer samples we have collected. We have reached the point where we can even detect phases 1 and 2 with very encouraging efficiency, and phase 3 with quite good efficiency. This is extremely important because half of all lung cancer diagnoses are currently only at stage 4, which is a death sentence. Even if we were only able to intercept the disease with good efficiency in phase 3, that would be a huge advance, much less in phases 1 or 2. It may very well be that in five or six years we will be ready to have a promising method for this in the first stage , perhaps not alone, but in combination with “low-dose computed tomography”.
Question: Are you working on this in Munich?
Krausz: Yes, at Ludwig Maximilian University, in collaboration with the Center for Molecular Fingerprinting Research in Budapest – by the way, a wonderful example of cooperation in how Europe should work. In Hungary, three years ago, we launched a study with 15,000 participants, which we will follow for at least ten years. The great advantage of this longitudinal study is that we will have blood samples from all stages of the disease. And we will be able to determine at what early stage a disease leaves its trace in the signal that we can detect using attosecond measurement technology.
Question: Where is the attosecond physics in this?
Krausz: We irradiate the blood samples with a femtosecond infrared pulse. This stimulates the molecules to vibrate, causing them to emit infrared waves. And we scan these infrared waves using attosecond measurement technology.
Question: The Nobel Prize Foundation asks laureates what nationality they would like to be awarded. Is it correct that he declared himself Hungarian – and if so, why?
Krausz: Yes, that is correct because the Nobel Prize Foundation named only one country at the prize ceremony. But I have Hungarian and Austrian citizenship, so I’m taken everywhere.
Question: How did you actually become an Austrian citizen?
Krausz: I simply requested it back then and it took me years to get it.
Question: Anton Zeilinger received the Nobel Prize in Physics last year, this year you are receiving this award, as is someone who did crucial work in Vienna – is this a coincidence, or can something be read into it?
Krausz: I think you can read something. I have had the great privilege of working in countries where scientific policy was obviously farsighted enough to invest in research whose immediate benefits could not be clearly seen. Our region is an excellent example of this. We would have been in trouble back then if anyone had asked us what it was for. And now, 15 or 20 years later, a highly interesting practical application is not only in sight, but also in the works.
And a good example is contagious. Even a country not as rich as Hungary is investing a lot in this matter; This Molecular Fingerprinting Center has already received funding of 200 million euros for the next seven years.
Question: You are still an honorary professor at the TU Vienna – how close is this cooperation and could it be expanded?
Krausz: Collaborations can always be expanded. There has been active collaboration over the years with the group of theoretical physicist Joachim Burgdörfer, which has resulted in a number of major publications. We are also constantly talking to my former Institute of Photonics at TU Vienna. With your boss Karl Unterrainer, a new direction is emerging where we want to use longer wavelengths, i.e. in the low terahertz range, especially in medical research.
(The interview was conducted by Christian Müller/APA)
(ABOUT THE PERSON: Ferenc Krausz, born on May 17, 1962 in Mor (Hungary), received his doctorate in 1991 at the Vienna University of Technology, where he perceived individual attosecond light pulses lasting 650 attoseconds for the first time in 2001 “For experimental methods of generating attosecond pulses of light to study the dynamics of electrons in matter”, he will receive the 2023 Nobel Prize in Physics together with his colleague Pierre Agostini, who works in the USA, and physicist Anne L’ Huillier, who works in Sweden. Krausz, who has Hungarian and Austrian citizenship, moved in 2003 as director of the Max Planck Institute for Quantum Optics in Garching, followed a year later by a professorship at the Ludwig Maximilians University (LMU) in Munich. In 2019 he co-founded the Center for Molecular Fingerprinting Research in Budapest, which he also directs.)