Researchers at Stony Brook University and the U.S. Department of Energy’s Brookhaven National Laboratory have successfully transmitted entangled photons through open air across a 13-mile free-space optical link on Long Island, marking the first demonstration of its kind in the United States. The August 19 experiment adds a wireless component to a 161-mile fiber-optic quantum network that officials now describe as the nation’s largest, backed by a $300 million New York State investment in Stony Brook’s Quantum Innovation Hub.
Key Takeaways
- Entangled photons traveled 13 miles (21 kilometers) through open air from Stony Brook University’s Quantum Watchtower to Brookhaven National Laboratory’s Quantum Lighthouse on August 19, 2026, at 12:26 a.m. ET.
- The free-space optical link integrates into an existing 161-mile, eight-node fiber-optic quantum network spanning Long Island and the New York metropolitan area.
- A third facility at Yale University in New Haven, Connecticut has been completed; researchers are preparing a 30-mile entanglement link across Long Island Sound.
- The $300 million Quantum Innovation Hub at Stony Brook, funded by New York State through Empire State Development, anchors the project alongside DOE and NSF support.
- The long-term goal includes transmitting quantum information to orbiting satellites, expanding the network from regional to global.
Photons Crossed 13 Miles Between Two Purpose-Built Rooftop Facilities
The experiment required infrastructure that did not previously exist at either institution. Stony Brook researchers constructed a Quantum Watchtower on the roof of the university’s Health Sciences Center, where a laser generated quantum states of light containing individual photons. Those photons exited the core of an optical fiber roughly 5 microns in diameter, less than one-tenth the width of a human hair, and traveled 21 kilometers through the atmosphere to Brookhaven’s Quantum Lighthouse in Upton, New York.
The Quantum Lighthouse sits atop the only building at Brookhaven National Laboratory with a clear line of sight to Stony Brook University. Justine Haupt, the Brookhaven Lab scientist who led the cross-institutional link project, and her team built the facility using expertise drawn from high-profile astronomy projects. The same adaptive optics technology that allows astronomers to collect and control light precisely was essential for preserving fragile quantum information across miles of turbulent atmosphere.
During the August 21 daytime demonstration, DOE Under Secretary for Science Darío Gil cut a ribbon blocking the receiving aperture at the Lighthouse, allowing photons to reach the detector. An ultrafast camera confirmed their arrival in an equally small optical fiber on the receiving end. But the team had already progressed beyond the daytime proof of concept. During nighttime tests on August 19, researchers successfully sent entangled photon pairs from a Stony Brook physics laboratory through fiber to the Watchtower, distributed them across the free-space optical link, and measured them at the Lighthouse, confirming that quantum entanglement held over the full distance.
The Wireless Link Extends a Network That Already Spans 161 Miles
The free-space optical connection does not replace fiber. It adds a wireless layer to a quantum network that Stony Brook and Brookhaven have built across Long Island and the New York metropolitan area over several years, currently connecting eight nodes through 161 miles of commercial fiber-optic cable. Through this network, researchers routinely transmit entangled photon pairs, particles that remain intrinsically linked by quantum mechanics regardless of the distance between them. Measuring one photon instantly reveals information about its counterpart, a property with direct applications in secure communications, quantum sensing, and networked quantum computing.
Eden Figueroa, director of Stony Brook’s Quantum Institute and endowed presidential professor of physics, noted that the fiber network is limited to telecom wavelengths, while the new wireless links allow researchers to explore infrared wavelengths native to quantum processors and related technologies. That distinction matters because it opens a direct path to creating entangled atomic systems across long distances, connecting quantum computers rather than simply transmitting encrypted signals.
Yale Facility Completed as Researchers Prepare a 30-Mile Link Across Long Island Sound
A third free-space optical facility at Yale University in New Haven, Connecticut has been completed. Researchers are now working to establish a 30-mile entanglement link from Stony Brook across the Long Island Sound to Yale, which would bridge the New York and Connecticut quantum nodes and extend the network beyond the boundaries of a single state.
Gabriella Carini, Brookhaven Lab’s Associate Laboratory Director for Discovery Technologies, described the satellite component as the next stage beyond the Yale connection. Transmitting quantum information through Earth’s atmosphere to orbiting satellites could bring secure quantum communications to rural or remote locations with limited ground-based infrastructure, transforming a regional network into a global one.
$300 Million State Investment Anchors Long Island as a Quantum Hub
Governor Kathy Hochul announced the $300 million Quantum Research and Innovation Hub at Stony Brook in September 2025, positioning it as New York’s premier facility for quantum science and technology research. Empire State Development funded the hub, which focuses on quantum communication and networking. The DOE Office of Science and the National Science Foundation provide additional support for the Brookhaven and Stony Brook research teams.
Stony Brook University President Andrea Goldsmith framed the milestone as part of a broader effort to build what the university calls a “Quantum Internet of Things,” with Long Island positioned as an innovation hub that could attract talent and investment in quantum technology. Brookhaven Lab Director John Hill described the free-space link as one milestone on a larger roadmap leading to distributed quantum systems that connect increasingly sophisticated devices for computation, communication, and sensing.
For New York, the investment reflects a state-level strategy to anchor an emerging technology sector in its public university system. Stony Brook co-manages Brookhaven National Laboratory for the DOE, one of only eight universities in the country with a role in operating a national laboratory, and the quantum network builds directly on that existing institutional relationship.
FAQs
What Is a Free-Space Optical Link in Quantum Networking?
A free-space optical link transmits photons carrying quantum information through the open atmosphere rather than through fiber-optic cables. The approach uses telescope-derived adaptive optics to keep photons on target across miles of turbulent air, enabling quantum connections where laying fiber is impractical or where different wavelengths of light are needed for specific quantum devices.
Why Does This Milestone Matter for Cybersecurity?
Quantum entanglement allows two parties to detect any attempt to intercept their communication, because measuring a quantum state changes it. A functioning quantum network built on entangled photons could provide a foundation for communications that are secure against both current and future decryption methods, including those enabled by quantum computers themselves.
How Does This Relate to the $300 Million Quantum Innovation Hub?
The Quantum Innovation Hub at Stony Brook, funded by New York State through Empire State Development, provides the institutional and financial infrastructure for long-term quantum research and education. The free-space optical link and the broader 161-mile network are direct outputs of the research programs the hub supports, with the goal of making Stony Brook a global center for quantum information science and technology.
