Researchers at Brookhaven National Laboratory and Stony Brook University have successfully transmitted light particles containing quantum information through open air between the two institutions, according to announcements by Brookhaven National Laboratory and Stony Brook University. The demonstration marks the first of its kind in the United States, utilizing a free-space optical link to extend the nation’s longest quantum network beyond conventional fiber-optic cables.
Bridging the Distance With Quantum Lighthouses
The system connects Stony Brook University’s Quantum Watchtower, situated on the roof of the university’s Health Sciences Center, with Brookhaven’s Quantum Lighthouse located on the BNL campus in Upton, New York, according to Brookhaven National Laboratory. During a daytime demonstration on August 21, researchers used a laser to generate quantum states of light containing individual photons inside the Stony Brook facility. These photons exited an optical fiber core measuring less than one-tenth the width of a human hair and traversed a 13-mile, line-of-sight path through the open air to a receiving camera atop the Brookhaven building.
Department of Energy Under Secretary for Science Darío Gil cut a ribbon blocking the receiving aperture during the event to allow the incoming photons to reach the detector. According to Darío Gil, the ability to connect quantum devices across distances is critical for the future of the field, noting that the free-space method achieves connections that traditional fiber infrastructure cannot.
Did you know?
The optical fiber core used to launch the photons from Stony Brook University is only about 5 microns in diameter, making it less than one-tenth the width of a human hair, according to Brookhaven National Laboratory and Stony Brook University reports.
Advancing Toward Entangled Photon Networks
Following the initial daytime tests, researchers advanced to experiments involving entangled photons—pairs of light particles intrinsically linked by the laws of quantum mechanics, according to Stony Brook University. During nighttime operations when background light levels drop, the team successfully transmitted entangled photons from the Stony Brook physics laboratory through fiber to the Quantum Watchtower, distributed them across the new free-space optical link, and received and measured them at the Brookhaven Quantum Lighthouse.
Stony Brook President Andrea Goldsmith stated that while widespread commercial adoption remains years away, the breakthrough points toward a transformation in computing capabilities. According to Andrea Goldsmith, quantum computers utilize the laws of physics to execute calculations in minutes that would require years or decades on classical systems, with potential applications spanning drug discovery, new material development, and financial market predictions.
Future Expansion Across Long Island Sound
The current installation forms a key component of the nation’s longest quantum network, which already links eight nodes across multiple institutions, according to Brookhaven National Laboratory. The next phase of development involves establishing a similar quantum lighthouse connection across the Long Island Sound to Yale University, expanding the free-space optical infrastructure.
According to Brookhaven National Laboratory Director John Hill, the future of quantum science relies on distributed systems where multiple devices work in tandem.
Frequently Asked Questions
What is a free-space optical link in quantum networking?
A free-space optical link transmits particles of light containing quantum information through the open air rather than relying exclusively on enclosed fiber-optic cables, according to Brookhaven National Laboratory.
Which institutions are involved in this quantum network project?
How far did the photons travel during the demonstration?
The light particles traveled across a 13-mile, line-of-sight path from the roof of Stony Brook University’s Health Sciences Center to the Brookhaven campus in Upton, New York, according to university and lab reports.
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