The Nobel academy said their studies had given humanity new tools for exploring the movement of electrons inside atoms, where changes occur in a few tenths of an attosecond – a unit so short that there are as many attoseconds in one second as there have been seconds since the birth of the universe.

The prize, which was raised this year to 11 million Swedish crowns (about $1 million), is awarded by the Royal Swedish Academy of Sciences.

“The ability to generate attosecond pulses of light has opened the door on a tiny, extremely tiny, time scale and it’s also opened the door to the world of electrons,” said Eva Olsson, member of the Nobel Prize in Physics Selection Committee.

It was once thought that these changes in electrons could not be seen, but the use of attosecond pulses has changed this, she added.

In an example of possible applications, the field held promise in areas such as a new in-vitro diagnostic technique to detect characteristic molecular traces of diseases in blood samples, the academy said.

Agostini and L’Hullier, both French-born though they work in the United States and Sweden respectively, were quickly congratulated by Sylvie Retailleau, France’s minister of Higher Education, who said they were a “great source of pride”.

L’Huillier, who received word she had won the prize in the middle of a lecture, told a news conference over the phone, “it is really a prestigious prize and I’m so happy to get it. It’s incredible.”

She works at Lund University in Sweden and Agostini is a professor at Ohio State University in the United States.

Hungarian-born Krausz is director at Max Planck Institute of Quantum Optics in Germany.

Physics is the second Nobel to be awarded this week after Hungarian scientist Katalin Kariko and U.S. colleague Drew Weissman won the medicine prize for making mRNA molecule discoveries that paved the way for COVID-19 vaccines.

Created in the will of dynamite inventor and businessman Alfred Nobel, the prizes for achievements in science, literature and peace have been awarded since 1901 with a few interruptions, becoming the arguably highest honour for scientists everywhere.

While the award for peace can hog the limelight, the physics prize has likewise often taken centre stage with winners such as Albert Einstein and awards for science that has fundamentally changed how we see the world.

Last year, Alain Aspect, John Clauser and Anton Zeilinger won the prize for work on quantum entanglement, where two particles are linked regardless of the space between them, something that unsettled Einstein himself who once referred to it as “spooky action at a distance”.

Announced on consecutive weekdays in early October, the physics prize announcement will be followed by ones for chemistry, literature, peace and economics, the latter a later addition to the original line-up.

By Niklas Pollard and Johan Ahlander

(Reporting by Niklas Pollard, Simon Johnson and Johan Ahlander in Stockholm; additional reporting by Terje Solsvik in Oslo and Elizabeth Pineau in Paris; Editing by Alexandra Hudson)