Your browser has javascript turned off or blocked. This will lead to some parts of our website to not work properly or at all. Turn on javascript for best performance.

The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here:

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Jan Marcus Dahlström becomes Wallenberg Academy Fellow

Jan Marcus Dahlström. Photo.
Jan Marcus Dahlström

The Knut and Alice Wallenberg Foundation has announced 29 new Wallenberg Academy Fellows. Jan Marcus Dahlström from Lund University is one of them. The Wallenberg Academy Fellowship is a five-year grant that provides the young researchers with opportunities to make important scientific breakthroughs by providing long-term research funding in Sweden.

How to measure an attosecond?

One attosecond is to one second what one second is to the age of the universe. Wallenberg Academy Fellow Jan Marcus Dahlström is developing a type of atomic clock that can measure attoseconds and be used in experiments involving extreme electromagnetic forces.

The Nobel Prize in Chemistry 1999 rewarded femtosecond spectroscopy, in which researchers study chemical reactions that occur in the space of a few femtoseconds (10-15 seconds). Now – two decades later – researchers in physics and chemistry are attempting to study processes that take place on the attosecond scale (10-18 seconds), including the photoelectric effect, in which electrons are emitted from a material that is illuminated with electromagnetic radiation.

Previously, ultrashort laser pulses have been used to measure the ejected electrons, photoelectrons. The problem is that the laser pulses and photoelectrons interact, so determining the time structure of the short laser pulses is impossible.

To measure time at the attosecond scale, Associate Professor Jan Marcus Dahlström at Lund University is developing a new kind of “clock”, in which he uses atoms with electrons that can be in something called a superposition state. He will investigate how the clocks affect each other, how they are affected by vacuum fluctuations in the electromagnetic field, how long it takes for a group of clocks to decompose and how this process can be controlled. The project will provide new opportunities for understanding the inner workings of matter.

Jan Marcus Dahlström is already part of a large-scale research project from the Knut och Alice Wallenberg Foundation that has led to an improved understanding of the photoelectric effect.

Learn more about the LU research project about the improved understanding of the photoelectric effect on the LU news website