US builds laser lab for world's largest vertical atom interferometer

The US Department of Energy’s Fermi National Accelerator Laboratory (Fermilab) has completed construction of a specialized laser laboratory to support the MAGIS-100 experiment, which features the world’s largest vertical atom interferometer. This 328-foot (100-meter) interferometer will use ultra-cold strontium atom clouds and precision laser pulses to investigate ultralight dark matter, a mysterious form of matter that constitutes about 85% of the universe’s mass but has never been directly observed. The interferometer operates by splitting and recombining atom clouds, detecting interference patterns that reveal tiny disturbances in gravitational fields potentially caused by interactions between dark matter particles, such as axions, and ordinary matter. MAGIS-100 is a collaborative effort involving Fermilab, Stanford University, Northwestern University, and other US and UK institutions. The experiment is housed in a deep shaft previously used for underground access, and the newly completed laser lab will accommodate the high-power laser systems essential for its operation. Researchers