Prof. Pierre Agostini was awarded the 2023 Nobel Prize in Physics for demonstrating experimental methods that generate attosecond pulses of light for the study of electron dynamics in matter, along with Ferenc Krausz and Anne L’Huillier. Their ingenious experimental designs and rigorous measurement techniques turned attosecond pulses into a new probe for exploring the microscopic behavior of matter. From electron rearrangements inside atoms to the ultrafast transfer of energy in molecules, attosecond technology is reshaping our understanding of light-matter interactions. Today, its impact extends far beyond fundamental physics, enabling real-time tracking of chemical reactions, the development of novel materials, and even the study of ultrafast processes in life sciences. Agostini’s scientific achievement lies not only in the technical breakthrough itself, but in opening a door to an unexplored world—where time is sliced into its finest fragments, and every instant of an electron’s motion becomes an observable reality.
Q1: You have demonstrated a way to create extremely short pulses of light that can be used to measure the rapid processes in which electrons move or change energy. What do you consider the most groundbreaking aspect of attosecond pulses?
A1: It is possible for the first time to follow the dynamic of electrons in matter.
Q2: Could you describe the most significant challenges you ever faced when generating and characterizing attosecond pulses?
A2: The generation of attosecond pulse trains (APT) is basically the same as that of high harmonics. It requires an intense laser, a relatively dense medium, and a good phase-matching. To generate isolated attosecond pulses (IAP), the driving laser pulse must be a few cycles long, which is rather challenging. Attosecond pulses are achieved by the total bandwidth of the harmonic emission according to Fourier.
Q3: How has the field of attosecond science evolved since your significant discovery?
A3: The field has mainly evolved toward applications. An exception is the generation of what is the current world record of 43 as IAP. This record is already 10 years old and difficult to break!
Q4: You developed RABBITT technology for characterizing attosecond pulses. What are the key points and the advantages of this technology?
A4: RABBITT is based on the photoionization process of a target atom by the high harmonics superposed to the delayed beam of the driving laser. This creates sidebands in the spectrum at frequencies in the middle of each couple of consecutive orders harmonics. Versus delay, the sideband amplitudes oscillate with a phase which is basically the phase difference between the two adjacent harmonics. This the key property which, with the spectral amplitudes of the harmonics, control the attosecond pulses of the APT. The technique is relatively simple and very robust.
Q5: What are the current limitations in attosecond science, and how might future research overcome them?
A5: One limitation is due to the dispersion of the recollision times versus energy (attochirp). This attochirp decreases as a function of the laser intensity and wavelength, so driving lasers with wavelengths between 5 and 10 µm will probably allow shorter APT.
Q6: How do you see attosecond science impacting other fields such as quantum computing, semiconductor technology, or medical imaging?
A6: A lot remains to be done! The harmonic spectrum has already been applied to semiconductor technology (because of the short wavelength advantage) and to medical field spectroscopy for early detection of cancers by Ferenc Krausz' group.
Q7: Do you foresee attosecond laser technology being integrated into industrial applications in the near future?
A7: Not sure. Perhaps it can be applied to improve atomic clock precision or to quantum computing. Industrial applications will be limited because the basic setup is complicated and requires delicate laser equipment.
Q8: Your discovery opens a "window of time" into the microscopic world, what are the next big milestones that researchers should aim for in attosecond science?
A8: Not sure. Taking images of very fast-moving objects. The attosecond microscope is perhaps the next technology in that direction.
Q9: How do you envision the role of artificial intelligence in advancing attosecond research?
A9: I don't see much help coming from AI. I might be wrong!
Q10: Looking back, what initially inspired you to pursue research in ultrafast optics and attosecond science? Can you share the story?
A10: One element was the collaboration with the LOA where femtosecond lasers were developed before Saclay. Another was the experience with ATI, which is the nonlinear device used in RABBITT.
Q11: Collaboration plays a vital role in research. Can you share your experience working with other scientists, including your fellow Nobel Laureates?
A11: Among all the people from whom I greatly benefitted in the Saclay/LOA time: Guillaume Petite, Nassem Rahman, and naturally Anne L'Huillier; the whole team from LOA has helped a lot teaching us the fs secrets. The role of Harm Muller from Amsterdam FOM was essential in the 2001 experiment, and the long-time collaboration with him was a strong component of my research. Alfred Maquet and collaborators were instrumental for the theory underlying RABBITT and without the work of the two students Pierre Mary Paul and Elena Toma, the 2001 experiment could not have succeeded. More recently Lou DiMauro at Ohio State gave me a second life after the mandatory retirement from Saclay. I was very happy they could all come to Stockholm. With Ferenc Krausz, unfortunately, our contacts were limited to the meetings of our European Network.
Q12: Many scientists struggle with balancing theoretical work and experimental validation. How did you approach this challenge in your own research?
A12: I am basically an experimentalist. I try either to verify some pre-existing theory (like ATI or RABBITT) or to try to interpret some observations using available theory. Sometime the experimentalist makes an observation that was not expected at all and which does not have an obvious explanation, as Anne's harmonics.
Q13: What advice would you give to young researchers who aspire to work in ultrafast optics and attosecond physics?
A13: Develop IR lasers and work to improve the resolution of APT which is still not very high.
Q14: How do you think fundamental physics research contributes to solving real-world problems?
A14: I still believe that fundamental physics is behind all applications and that no "real-world" problems could be solved without understanding the fundamentals.
Q15: How has winning the Nobel Prize influenced your research and your perspective on science?
A15: The Nobel Prize was a personal surprise. I hope that the prestige of the prize will help funding and attract talented young people.
Q16: Your remarkable discovery showcases a paradigm of breaking the boundary of disciplines. Our journal eLight also aims at expanding the boundary of optics and excavating transformed research to change the world. What are your suggestions and expectations for eLight?
A16: There is a lot of our world that we understand through light, from atomic structure to the size of the Universe. Laser light has opened an abundance of new phenomena with high intensity and now with extremely short pulses. Both aspects should lead to discoveries worth the attention of eLight.
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References
DOI
10.1186/s43593-025-00091-z
Original Source URL
https://doi.org/10.1186/s43593-025-00091-z
About eLight
The eLight will primarily publish the finest manuscripts, broadly covering all sub-fields of optics, photonics and electromagnetics. In particular, we focus on those emerging topics and cross-disciplinary researches related to optics.