The Royal Swedish Science Academy has awarded the 2023 Nobel Prize in Physics to three scientists. The laureates are Pierre Agostini of The Ohio State University, Columbus, USA, Ferenc Krausz working at the Max Planck Institute of Quantum Optics in Garching and the Ludwig-Maximilians-Universität in Munich, Germany, and Anne L'Huillier of Lund University in Sweden. The Nobel Prize committee recognized their achievements in experimental methods for generating extremely short, attosecond, pulses of light to study the behaviour of electrons in atoms and molecules.
The phenomena occurring in the microworld inside atoms and molecules, especially those involving electrons, are extremely fast. The time scale for these phenomena is expressed in attoseconds (abbreviation: as), i.e. units of time 1018 (or trillion) times smaller than a second. Experiments to identify them are therefore a great challenge for physicists. The way to make progress in this area is to use suitably short pulses of light, which, like a flash, that allows them to be "illuminated" for an extraordinarily short moment and thus avoid "blurring of details."
The three laureates have developed a technique for producing such extremely short pulses. Their achievement is a breakthrough in research that opens up a wide range of possibilities for understanding the mechanisms that govern the behaviour of electrons, their motion and energy.
In 1987, Anne L'Huillier found a way to obtain short pulses of light by transmitting infrared laser radiation through a noble gas. As a result of the interactions taking place, the electrons gained additional energy later radiated as a short pulse of light. In 2001, Pierre Agostini received and studied a series of light pulses, each lasting only 250 attoseconds. At the same time, Ferenc Krausz developed an experimental method to isolate a single light pulse lasting 650 attoseconds.
Attosecond pulses provide opportunities for studies previously unavailable, such as making it possible to measure the time it takes for an electron to detach from an atom and to examine how this time depends on how tightly the electron is bound to the atom's nucleus and also to reconstruct how the electron cloud oscillates in molecules and materials.
The techniques for generating attosecond pulses will find applications in many fields, such as in electronics attosecond pulses will help understand and control the behaviour of electrons and in medical diagnostics and can be used to distinguish and identify molecules.
