Miniaturized laser technology paves the way for fundamental physics experiments in space

An international research team has developed a miniaturized laser system that enables the generation of high-flux Bose–Einstein condensates (BECs) consisting of two different atomic species—rubidium and potassium—under microgravity conditions. This breakthrough was achieved by the Mainz research group at Johannes Gutenberg University Mainz, in collaboration with universities and institutes in Berlin.

The MAIUS-B apparatus, housed in the Einstein Elevator at Leibniz University Hannover, allowed the scientists to study the unique properties of these BECs in a state-of-the-art optical system. While BECs were previously generated in space during the MAIUS-1 mission, the challenge of simultaneously cooling and manipulating two distinct atomic species was unprecedented.

To overcome this, the researchers created a compact laser system with optical interfaces that ensured precise control over the atoms, even in the harsh environment of a rocket launch and varying temperature conditions. The stable Zerodur-based optical interfaces, developed in partnership with the University of Hamburg, maintained atomic control despite the extreme mechanical and thermal stresses.

This technology marks a significant milestone in the use of quantum sensors for spaceborne experiments, paving the way for future projects like the German–American BECCAL atom laboratory aboard the International Space Station. Such systems will enable scientists to conduct precision tests of Einstein's equivalence principle by measuring whether different atomic species experience the same acceleration during free fall.