Brookhaven National Laboratory and Stony Brook University researchers transmitted quantum information through 13 miles of open air, marking the first U.S. demonstration of its kind and extending their record-setting Long Island quantum network beyond fiber-optic cables using a novel free-space optical link.
Researchers in New York have pushed quantum communication out of the laboratory and into the open atmosphere. During a daytime demonstration, scientists transmitted light particles containing quantum information across a 13-mile stretch between Stony Brook University and Brookhaven National Laboratory, according to reporting from The Quantum Insider. The milestone marks the first time such a wireless transmission has been successfully demonstrated in the United States, expanding an existing network that spans 161 miles across Long Island and the New York metropolitan area.
Stony Brook University and Brookhaven Lab Establish Open-Air Link
The transmission took place during tests conducted by teams from the U.S. Department of Energy’s Brookhaven National Laboratory and the State University of New York at Stony Brook. During the daytime demonstration, researchers used a laser to generate quantum states of light in Stony Brook University’s state-of-the-art Quantum Watchtower, located on the roof of the Health Sciences Center in Stony Brook, New York. The photons exited an optical core only about 5 microns in diameter — roughly one-tenth the width of a human hair.
From there, the light particles traveled 21 kilometers through open air to Brookhaven’s Quantum Lighthouse in Upton, New York. In the Lighthouse, Department of Energy Under Secretary for Science Darío Gil cut a ribbon blocking the receiving aperture, allowing the photons to reach an ultrafast camera that marked their arrival in a similarly narrow optical fiber.
Gil added that the achievement supports the agency’s Genesis Mission, aiming toward an interconnected research ecosystem where advanced computing, artificial intelligence, and quantum technologies operate together.
Overcoming Atmospheric Turbulence With Adaptive Optics
Unlike traditional fiber-optic cables that shield light from environmental disturbances, transmitting delicate quantum states through the atmosphere presents severe engineering hurdles.
To counteract these distortions, Justine Haupt of Brookhaven Lab spearheaded the development of specialized telescope technology and mirrors capable of real-time correction. Haupt’s team designed adaptive optics that warp mirrors thousands of times per second to maintain signal clarity.
Haupt noted that while her team brought experience building components for the Vera C. Rubin Observatory, the free-space optical link proved uniquely challenging because it traverses the entire turbulent ground layer rather than observing through a high-altitude atmospheric layer.
Nighttime Tests Deploy Entangled Photons Across Long Island
Following the daytime laser tests, researchers advanced to nighttime experiments designed to reduce background light interference. During these dark-sky tests, the team distributed entangled photons—pairs of light particles intrinsically linked by quantum mechanics—across the new wireless link.
The setup involved sending entangled pairs from a Stony Brook physics laboratory to the Quantum Watchtower via fiber, distributing them across the 13-mile wireless link, and successfully measuring them at Brookhaven’s Quantum Lighthouse. Because entangled particles remain linked across distance, measuring one instantly reveals information about its counterpart, a property often described as spooky action at a distance
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Next Steps for the Regional Quantum Expansion
The free-space optical link currently connects facilities at Brookhaven National Laboratory and Stony Brook University. However, the multi-institutional collaboration has already begun developing a third facility at Yale University in New Haven, Connecticut, which will add a planned 30-mile link to the network.
Researchers note that while long-distance fiber networks are traditionally restricted to telecom wavelengths, exploring wireless links offers a direct route toward connecting distributed quantum systems and eventually exploring satellite-based connections.
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