The Pentagon’s research arm has set a new benchmark for long-distance wireless power delivery, pushing a field once seen as theoretical into a realm that looks increasingly practical.
The Defense Advanced Research Projects Agency (DARPA) confirmed that its Persistent Optical Wireless Energy Relay (POWER) program successfully sent more than 800 watts of power across 8.6 kilometers using a focused infrared laser.
The test, carried out in the New Mexico desert, marks the farthest and strongest demonstration of optical power beaming to date.
The accomplishment closes out the first stage of a three-phase effort aimed at creating a network of airborne and ground-based relays capable of routing energy like data. If the project reaches full maturity, it could allow aircraft, satellites, and remote outposts to receive power without direct fuel deliveries or bulky energy storage.
Before this latest round, the longest verified power-beaming runs were dramatically shorter and weaker. Earlier tests achieved about 230 watts at 1.7 kilometers and an unspecified amount at 3.7 kilometers. The New Mexico experiment pushed both metrics far beyond previous limits.
A quick-build system designed for proof of concept
Paul Jaffe, who leads the POWER team, noted that efficiency was not the priority for this stage. The receiver converted roughly 20 percent of the incoming laser energy into usable electricity, far below what specialized photovoltaic materials can achieve under ideal conditions. But the aim was to assemble a functioning system fast, not squeeze every watt from the setup.
To hit their tight timeline, the team relied on off-the-shelf solar cells rather than purpose-built ones optimized for laser wavelengths.
A conical mirror inside the receiver redirected the incoming infrared beam toward those cells, which then produced electricity long enough to sustain the 800-watt output for about half a minute. In practice, the receiver ran even longer than reported, according to Teravec Technologies founder Raymond Hoheisel, whose company developed the device.
Hoheisel said the real breakthrough was demonstrating that such a system can be built quickly and affordably. From planning to operation, the entire test platform came together in about three months.
DARPA did not disclose the total power emitted by the laser source, only the measurable output delivered at the receiving end. Still, the numbers were high enough to surprise the project’s own researchers. “The record wasn’t the goal,” Jaffe said, describing the result as an unexpected milestone rather than a planned target.
Why DARPA is leaning toward optical power
Power beaming is not a new idea, but most long-range experiments have used radio or microwave frequencies. Those systems rely on beamforming, precisely shaping the radio waves so the energy travels in a tight column rather than radiating outward like a broadcast signal.
The drawback is that radio wavelengths are long, which forces engineers to build large antennas to maintain focus. Even then, the beam spreads more than scientists want.
Infrared lasers offer a different path. Their much shorter wavelengths allow for a sharper, more concentrated beam that holds its shape over long distances. This makes optical systems attractive for airborne relays, where weight and size constraints rule out massive antenna structures.
Laser transmission does face its own limitations. Fog, clouds, and heavy moisture can distort or scatter light, which is why microwaves still have an advantage in difficult weather. But when conditions are clear, the precision of optical energy transfer allows for smaller hardware and finer control.
For DARPA’s vision, creating a chain of airborne nodes that pass energy from one platform to another, the precision of lasers appears essential. “If optical doesn’t work, nothing will work for this purpose,” Jaffe said.
Unexpected insights that could shape future designs
The team stumbled on other promising techniques as the project progressed. They learned that diffractive optics, components that manipulate light using microscopic patterns, may outperform traditional mirrors and lenses when dealing with single-wavelength laser beams.
They also developed additively manufactured optical parts with built-in cooling, which could reduce size and weight even further.
These discoveries, Jaffe said, were not part of the original plan. Yet they may open new directions for future experiments, both within POWER and in civilian research.
The next phases of the program will move toward building the relay aspect itself, extending not just the distance of a single beam but creating a chain capable of passing energy across even longer ranges.
DARPA’s test doesn’t mean the technology is ready for field deployment, but it sends a clear signal: wireless power transmission is no longer science fiction. It’s engineering, and it’s advancing faster than expected.