Plate Nº 10 · recorded October 13, 2026
PhysicsReported finding
Laser 'Lightsaber' Antenna Transmits Radio Waves at 30 MHz
NC State engineers fired a laser through air to create a plasma 'lightsaber' antenna that transmitted radio at 30 MHz — the first working demonstration of its kind, published in IEEE Journal of Microwaves.
By Elena Vasquez3 min read683 words
In brief
- NC State researchers demonstrated the first working laser-generated plasma-filament antenna, transmitting at 30 MHz (VHF band).
- The findings were published October 9, 2026, in the open-access IEEE Journal of Microwaves (DOI: 10.1109/JMW.2026.3722433).
- A contactless metal-ring capacitor feed delivers the radio signal to the plasma without physical contact.
- Laser settings control the filament's length, and beam steering controls its angle — no moving parts.
- Reception capability and broad-frequency operation remain untested; the work is a proof of concept.
Engineers at North Carolina State University have demonstrated the first antenna made from a laser-generated beam of plasma, transmitting radio waves at 30 megahertz — the first proof that such an antenna can work at all. The glowing filament looks, by the researchers' own description, like a lightsaber.
Instead of a metal rod, the device uses a narrow channel of plasma — the electrically charged "fourth state of matter" — created directly in the air by a carefully controlled laser. The findings appeared October 9, 2026, in the open-access IEEE Journal of Microwaves.
"The plasma beam antenna looks like a lightsaber and is tunable, meaning we should be able to transmit across a broad range of frequencies," said Prya Darshni, corresponding author and Ph.D. student at NC State.
How does a laser become an antenna?
A conventional antenna's length determines which frequencies it sends and receives efficiently. Change the length, and you change the frequency. That usually means moving parts or complicated engineering — a real burden for spacecraft, where gear must be light, compact and reliable.
The NC State team skipped the metal entirely. They fire a laser through the air, tuning its power and beam diameter to ionize a thin channel of air — stripping electrons from atoms — and producing a plasma filament. That filament is the antenna.
One problem remained: how to feed a radio signal into plasma nobody touches. Their answer is a contactless feed. A metal ring acts as a capacitor — a component that stores energy in an electric field. The laser passes through the ring's center, and the plasma filament threads the capacitor's field. A radio-frequency generator charges the capacitor, the field couples to the filament, and the filament radiates at the supplied frequency.
The demonstration ran at 30 MHz, inside the very high frequency (VHF) band used for FM radio and other broadcast services. That is the mechanism. The headline is that it worked at all.
Why does tunability matter?
Because the antenna exists only as long as the laser shines, its size and direction can change on demand.
"By controlling the parameters of the laser, you can control the characteristics of the plasma filament — including its length," Darshni said. "This is valuable for applications where you need an antenna that can sweep all frequencies."
The angle can be steered too, simply by shifting the laser's direction. That could aim radar sweeps or strengthen signal reception without the mechanical gimbals conventional antennas need.
"This is an exciting new concept that enables one to be able to have a customized antenna without complex mechanical deployment mechanisms," said co-author Paul Franzon, Cirrus Logic Distinguished Professor of Electrical and Computer Engineering at NC State.
Where could it fly?
Satellites and space exploration top the list. Launch vehicles impose strict weight and size limits, and large antennas must fold up for launch and unfold in orbit. A laser-generated antenna would need no such hardware.
"In low earth orbit, there is sufficient air to form a plasma," Franzon noted — the approach could work in the thin atmosphere hugging the planet.
That's the promise. The caveats are real. The team has demonstrated transmission only; nobody has yet shown the plasma antenna can receive signals, though Darshni said "there's no reason to believe it wouldn't also work as a receiver." Operation across a broad frequency range also remains untested, and performance under genuine space conditions will require years of additional research.
What's the takeaway?
"This is the first step, but it is a big step — it is the first time anyone has ever demonstrated that plasma-filament antennas can work," Darshni said. "Now that we've shown it is possible, we can begin improving its performance."
Arthur Dogariu, affiliated with Texas A&M University and Princeton University, co-authored the paper and contributed the experimental measurements. The team also credited Chris Hewett, Byron Goode and Joe McElveen of NC State's Instrument Shop for manufacturing the experimental components.
A laser, a ring of metal and plain air made an antenna. The rest is engineering.
via news.ncsu.edu (Original)
More from Elena Vasquez
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Correspondent covering money, funding and market shifts around general science news at SciBeat.
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