Walk into the right lab at NC State and you might think someone left a movie prop running. A thin column of glowing plasma hangs in the air — no casing, no wires, no metal of any kind — looking every bit like a lightsaber pulled from a film set. But it isn’t a prop. It’s a functioning antenna, and it’s transmitting radio waves.
Researchers have now demonstrated for the first time that a laser-generated plasma filament can act as a radio-wave-transmitting antenna. That raises a question which would have seemed purely theoretical not long ago: what happens when you build an antenna out of light and ionized air instead of metal?
A beam of plasma that transmits radio waves
The NC State team’s findings appear in the IEEE Journal of Microwaves — the first peer-reviewed demonstration of a laser-induced plasma filament functioning as a radio-transmitting antenna. The device successfully broadcast at 30 MHz, placing it in the VHF radio band used by everything from aviation communications to FM broadcasting.
The filament forms when a high-powered laser travels through open air, ionizing a narrow channel of molecules — stripping electrons and producing plasma, the fourth state of matter. What remains is a thin, glowing column that interacts with electromagnetic fields in ways ordinary air simply can’t.
Corresponding author Prya Darshni, a Ph.D. student at NC State, calls it “the first time anyone has ever demonstrated that plasma-filament antennas can work.” The paper frames the result as a proof-of-concept — a significant step, not a finished product.
Why conventional antennas hit a wall
Traditional metal antennas are constrained by their own geometry. An antenna’s physical length determines which frequencies it handles efficiently, so changing frequency often means changing the antenna itself — retractable booms, motorized mounts, switching arrays — all of which add weight, complexity, and points of failure.
In space, those trade-offs get especially painful. Spacecraft operate under strict mass and volume limits, and mechanical deployment systems that fold for launch and unfold in orbit are a persistent engineering headache. A single stuck hinge can silence a satellite.
The NC State team asked a direct question: could a laser create an antenna in the surrounding air itself, skipping the metal and the mechanics entirely? Their answer, now published, is yes.
How a laser becomes an antenna
The process starts with careful control of laser power and beam diameter. Dial in the right parameters and the beam ionizes a narrow channel of air molecules, producing a plasma filament — concentrated, electrically charged, and ready to interact with radio-frequency fields.
Generating the filament was only half the problem. Delivering a signal to plasma without physically touching it required a separate engineering solution: a metal ring positioned around the filament, acting as a capacitor.
A radio-frequency generator feeds a signal into that ring. The resulting electromagnetic field couples directly with the plasma — no wire, no contact, no physical connection of any kind. The filament absorbs the energy and radiates radio waves at the supplied frequency. The entire transfer is field-based.
An antenna you can steer and resize on demand
Because the antenna exists only as long as the laser fires, its length isn’t fixed by manufacturing — it’s set by adjusting laser parameters in real time. Need a shorter antenna for a higher frequency? Change the beam. No retraction required.
Beam steering adds another layer of flexibility. Shifting the direction of the laser shifts the angle of the plasma filament, redirecting transmissions without any moving mechanical parts. Darshni points out that this matters for radar systems sweeping directions and for communications links that need to hop across frequencies quickly.
Receiving capability and operation across a broader frequency range haven’t been tested yet. The researchers say they see no physical reason the approach wouldn’t work in both modes — it’s a gap in testing, not a barrier in principle.
Space, satellites, and what comes next
Satellites are among the most compelling near-term targets for this technology. Deployable antenna structures — folded for launch, extended in orbit — add mass, volume, and mechanical risk. A laser-generated antenna could let a spacecraft reconfigure its transmission profile on demand, without booms or hinges or anything that can jam.
Co-author Paul Franzon notes a key atmospheric detail: in low Earth orbit, enough air remains to sustain a plasma filament. That doesn’t guarantee the system will work in space conditions, but it removes one obvious objection.
The team is clear-eyed about where things stand. Efficiency needs to improve, and real-world conditions need testing. The 30 MHz demonstration is a foundation, not a finish line. The next question is whether researchers can push the plasma filament across a wider frequency range — and whether the contactless feed design scales to the power levels practical applications demand. If those tests hold up, an antenna built from light — tunable, steerable, free of moving parts — stops being a lab curiosity and starts looking like infrastructure.
Learn more about this invention here: Prya Darshni, Arthur Dogariu, Paul D. Franzon. Laser-Induced-Plasma-Filament Antenna Transmitting 30 MHz VHF. IEEE Journal of Microwaves, 2026; 6 (5): 1174 DOI: 10.1109/JMW.2026.3722433
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