Deutsch Intern
  • Lab photo lightsaber
Prof. Dr. Tobias Brixner


Short movie "Femto Stars" (6-min summary for those in a hurry)

A lightsaber is a fictituous fencing weapon from the "Star Wars" Universe of the movie franchise of the same name created by film maker George Lucas. There have been numerous discussions throughout the years whether one could build a real lightsaber. The video "Femto Stars" is a short summary of how we realize a kind of "lightsaber" on the basis of femtosecond laser pulses; the scientific background was discussed in a lecture including experiments at the public event Highlights der Physik 2021.

Popular-science lecture (complete version)

Are lightsabers pure fiction? Most people argue that a laser beam propagates unhindered until it hits an obstacle, and therefore spatially limited lightsabers are physically impossible. The film "Femto Stars" and the photo in the header of this page show that you can apparently produce light effects of finite length. How does this work? What is it good for?

The recorded lecture "Can we build a lightsaber?" by Prof. Brixner with fencind expert Constantin Krause (edited version of the YouTube-Livestream  from the  "Highlights der Physik 2021", in German), which can be accessed below, uses an analogy with music to show how ultrashort laser pulses are created. Turning light on and off in just a few femtoseconds (i.e., millionths of a billionth of a second) opens up a whole new world of opportunities to track and even control extremely fast physical processes in real time. The reality even surpasses the "Star Wars" fiction, because in our research we penetrate with precision down to the atomic level and "cut" chemical bonds in a molecule in the context of "quantum control". In addition to this "femtochemistry" one can use ultrafast spectroscopy, for example, to temporally resolve the biological processes of photosynthesis or vision. A specialty of our research group is multidimensional spectroscopy, which provides comprehensive information. Femtosecond laser pulses are also used in medicine, for example in the "femto-LASIK" eye surgery, whose functional principle is based on the "lightsaber" effect.

Further publications

Alternative lightsaber concepts

There are many suggestions on how to build a lightsaber on the internet, especially on YouTube. The following selection has nothing to do with femtosecond lasers. Make your own judgment of how successful these trials are. If you would like to work with the "Femto Stars Lightsaber," you should become part of our team, as we use filaments in research daily to create broad spectra...