2023 Physics Nobel Prize

2023 Nobel Prize in Physics

The Royal Swedish Academy of Sciences  awarded the Nobel Prize in Physics 2023 to

Pierre Agostini
The Ohio State University, Columbus, USA

Ferenc Krausz
Max Planck Institute of Quantum Optics, Garching and Ludwig-Maximilians-Universität München, Germany

Anne L’Huillier
Lund University, Sweden

“for experimental methods that generate attosecond pulses of light for the study of electron dynamics in matter”

The three Nobel Laureates in Physics 2023 are being recognised for their experiments which 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.

In order to investigate really brief events, we need special technology. In the world of electrons, changes occur in a few tenths of an attosecond. An attosecond is  an extremely short interval of time, so short that there are as many attoseconds in one second as there have been seconds since the birth of the universe.

The Nobel laureates’ experiments have produced attosecond pulses of light and demonstrated that these pulses can be used to provide images of processes inside atoms and molecules.

The birth of attosecond science can be traced to 1987, when Anne L’Huillier and coworkers first observed optical harmonics, produced by focusing intense laser pulses into a noble gas medium. Anne L’Huillier discovered that many different overtones of light arose when she transmitted infrared laser light through a noble gas. These overtones are caused by the laser light interacting with atoms in the gas; it gives some electrons extra energy that is then emitted as light. Anne L’Huillier has continued to explore this phenomenon, laying the ground for subsequent breakthroughs.

Attosecond ‘pulse train’ was experimentally obtained for the first time in 2001 by Pierre Agostin and co-workers in Paris.  Agostini succeeded in producing and investigating a series of consecutive light pulses, in which each pulse lasted just 250 attoseconds. At the same time, Ferenc Krausz was working with another type of experiment, one that made it possible to isolate a single light pulse that lasted 650 attoseconds.  Anne L’Huillier  then produced a laser pulse lasting just 170 attoseconds.

We can now open the door to the world of electrons. Attosecond physics gives us the opportunity to understand mechanisms that are governed by electrons. It is now possible to observe the fleeting spatial distributions and energies of electrons within atoms and molecules with unprecedented precision. Attosecond pulses have been used to investigate fundamental processes such as the decay of highly excited core-hole states, electron motion associated with quantum mechanical superpositions of valence electronic states, and time delays in the photoionisation of different atomic or molecular orbitals.