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The Expert Answers Q&As and columns reflect the expertise and opinions of individual faculty members and do not necessarily represent an official policy or position of the university.

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Guillaume Laurent

Guillaume Laurent is a professor of physics in Auburn University's College of Sciences and Mathematics.

On Oct. 3, the 2023 Nobel Prize in Physics was awarded to a team of researchers comprised of Pierre Agostini from The Ohio State University, Ferenc Krausz of the Max Planck Institute of Quantum Optics (Germany) and Anne L’Huillier of Lund University (Sweden). Their groundbreaking research led to the development of the attosecond pulse of light (1 attosecond = 10-18 second) that ultimately allows for the observation of fast-moving electrons in real time. For comparison, an attosecond is to a second what a second is to the age of the universe.

One of Auburn University’s cutting-edge laboratories — led by Professor Guillaume Laurent — conducts similar novel research. Laurent explains the significance of the discovery for his research field in particular, and more generally for humanity, and outlines some of the work being done in his own laboratory, the Auburn Source of Attosecond Pulses (ASAP) lab. His laboratory was established in 2016 and is currently supported by the U.S. Department of Energy’s Office of Science and the United States Air Force Office of Science Research (AFOSR).

Q: Can you describe the significance of this Nobel Prize for the field of physics?

GL: Their discovery has allowed us to solve a long-lasting problem in physics: observing in real time the motion of microscopic objects, like electrons, in matter. For more than a century since the development of quantum mechanics, which rules the behavior of the microscopic world, physicists have only been able to reconstruct the electron motion indirectly from some measurements and based on some assumptions, simply because they did not have the proper tools for a direct measurement.

Q: What was so revolutionary or novel about the award-winning team’s research that earned it one of the most coveted prizes in the world?

GL: Their discovery sparked the emergence of the new field of “attosecond science,” which is currently spreading worldwide. With the advent of the attosecond pulse of light, we now have the capability to directly observe and eventually control electron motion in matter. This could lead to huge repercussions in many fields in science and engineering in the near future.

Q: Talk about your lab and the work you are conducting there.

GL: Our laboratory was established in 2016. It took us a few years to get the proper environment to perform this kind of research, as manipulating attosecond pulses requires the most stringent level of stability in the room. To give an example, the sole presence of a person standing in the room next to the experimental setup disturbs the measurement! Over the years, we have learned how to perform such attosecond measurements on a daily basis.

Currently, our principal directions of research include the development of novel sources of attosecond pulse of light in the Extreme UltraViolet (EUV) wavelength regime with tailored temporal profile, the development of innovative methods to characterize such attosecond pulses and the study of ultrafast dynamical processes in atoms, molecules and complex systems down to the attosecond time scale. We have developed new methods to track electrons’ motions in such systems, and we are now investigating the correlated electron dynamics in molecules, for example.

Q: Where do you see the future of this aspect of physics going, and what are some practical, real-world applications of this type of research?

GL: Being able to observe electron motion in real time will ultimately allow us to control it also in real time. This has some important implications in chemistry, for example, as we now have tools to control chemical reactions directly at the atomic level by using such novel attosecond pulses of light. Controlling chemical reactions will allow for the development of new materials, and ultimately, new technologies.