Researchers just sent quantum information 13 miles through open air for the first US demonstration

[DeadChat]

Scientists at Brookhaven National Laboratory and Stony Brook University pulled off the first free space optical quantum link demonstration in the United States this week, transmitting single photons and entangled photon pairs across thirteen miles of open atmosphere between two purpose built facilities. The photons traveled from Stony Brook's Quantum Watchtower to Brookhaven's Quantum Lighthouse in Upton, New York, a building specifically constructed because it's the only Brookhaven structure with a clear line of sight back to the university.

The scale involved here is hard to picture. Photons exited a fiber optic core roughly five microns wide, thinner than a tenth of the width of a human hair, then traveled thirteen miles through open air before landing in an equally tiny receiving fiber on the other end. Getting that kind of precision over that kind of distance required serious work on adaptive optics to keep the beam stabilized against atmospheric turbulence, wind, and temperature shifts along the path.

This free space link plugs directly into an existing 161 mile, eight node fiber optic quantum network that already connects institutions across Long Island and the New York City area. Adding a wireless component matters because fiber based quantum networks face real physical limits, since photons degrade as they travel through glass and eventually need expensive repeater stations to go any further. Free space links skip that constraint entirely for line of sight distances, at the cost of being vulnerable to weather and requiring precise aiming.

A third identical facility is already built at Yale University in New Haven, Connecticut, and the team is preparing to demonstrate a longer thirty mile link across Long Island Sound next. Eden Figueroa, who directs Stony Brook's Quantum Institute, framed this as a shift away from just building individual quantum devices in a lab and toward actively engineering large connected quantum systems, which is a meaningfully different phase of the field than most of the headlines about single processors tend to suggest

New York State researchers transmit quantum information 13 miles through open air | Fingerlakes1.comwww.fingerlakes1.com

[Seb51]

Thirteen miles doesn't sound like much until you remember they're keeping single photon level signals coherent through open atmosphere the entire way. That's a very different engineering problem than routing photons through a sealed fiber

[Leo29]

The Yale connection is the part I'm most curious about going forward. Thirty miles across open water introduces a totally different set of atmospheric variables compared to a line of sight path over land. Humidity and salt spray near a large body of water can mess with beam quality in ways a purely terrestrial link wouldn't experience nearly as much. Curious whether they've published anything yet about how they're planning to compensate for that specifically