Researchers at Texas A&M's Lab for Advanced Nanophotonics built metasurface 'metajets' (silicon nanopillars smaller than a human hair) that achieve 3D propulsion and levitation using only light pressure through spatially distributed phase gradients. Unlike previous optical…
Subtitle: A Texas A&M lab has built the smallest thing that moves without carrying its own power. The hard part is making it matter.
Propulsion has always been a story about shedding weight.
Steam engines dragged their fuel aboard. Rockets carry their oxidizer. Jet engines burn what they breathe. Every era of locomotion has been defined by the same imperative: get the energy source out of the vehicle and into the world. The locomotive didn't tow a coal car because it was fashionable. It towed it because no one had figured out how to put the boiler in the ground.
A team at Texas A&M University has now taken that logic to what may be its terminal extreme. In a paper published in the inaugural issue of the journal Newton, researchers describe building objects that move through three-dimensional space using nothing but the pressure of light. No fuel tank. No thruster. No onboard energy of any kind. The device — a metasurface studded with silicon nanopillars, smaller than a human hair in every dimension — is pushed, lifted, and steered by photons alone.
"We achieve that by creating a spatially distributed phase gradient with deliberately arranged silicon nanopillars," the authors write. Unlike conventional photon pressure, which pushes an object directly backward, the gradient redirects incoming light in a chosen direction, generating controlled force along multiple axes simultaneously. The result, as the paper's title puts it, is "optical propulsion and levitation of metajets00073-3)." The work was led by Shoufeng Lan, a researcher in the Lab for Advanced Nanophotonics, along with colleagues including Kaushik Kudtarkar.
That phrasing — "levitation" alongside "propulsion" — is the actual news. Previous optical propulsion demonstrations moved objects along a single axis, forward and back, like a paddle ball on a string. Getting an object to rise, fall, or drift sideways required changing the beam geometry itself, not the object. What Lan's team demonstrates is the object controlling its own trajectory: the metajet maneuvers in three dimensions while the light source stays fixed.
The finding that makes this more than a lab curiosity is one of scale. The metaphotonic force the researchers describe "augments with increased light power but is not limited by the size of the metajets." This matters because conventional rocket physics has an immutable rule: thrust depends on how much propellant you throw backward. The metajet physics appears to break that dependency. More laser power produces more force without the device needing to grow, which is the property you'd need if you're trying to push something bigger than a speck.
The paper is careful not to claim what it doesn't. "At sufficient optical power," the authors note, metajet physics "could unleash new opportunities for metaphotonic control in large settings, such as interstellar light sails." That qualifier — sufficient — is doing enormous work. The current devices are tens of microns. A human hair is roughly 70 microns. The kind of interstellar hardware that Breakthrough Starshot, the billion-dollar interstellar initiative announced in 2016, envisioned would require gram-scale sails — roughly a million times larger. No one has demonstrated that metajet physics works at that scale, or that it can be manufactured at the precision required, or that the light source required is tractable.
Breakthrough Starshot itself has had a complicated few years. After an intensive Phase I research program, the project was "put on hold" in 2024, in the words of executive director Pete Worden, who said the team was "working to transition portions to others." Jim Benford, a former member of the Breakthrough Starshot sail team, argues in an analysis published on Centauri Dreams that Phase I was substantively successful — that it identified credible solutions to the key show-stoppers for beam-driven propulsion, including sail materials, beam-riding stability, and the beamer array. "The principal issues for Starshot were found to have credible solutions," Benford wrote. He estimates Phase I cost roughly $25 million, not the $4.5 million cited in a critical Scientific American article that characterized the project as a quiet demise rather than a pause.
What the Texas A&M paper does is provide a specific, peer-reviewed physics result that the Starshot transition team — or anyone else working on beam-driven propulsion — can point to as a foundation. It doesn't prove the engineering. It demonstrates the physics at a scale far below what interstellar flight requires.
The gap is the story's honest burden. Scaling metajets from micron-scale laboratory demonstrations to gram-scale interstellar hardware is not a solved problem. The physics may be sound; the engineering is measured in decades. Sustained high-power laser delivery over interstellar distances, beam precision at scales smaller than a millimeter over light-years, heat management, material stress — these are not theoretical blockers. They are the next mountain. Researchers at Caltech and the Rochester Institute of Technology are working on comparable optical propulsion questions, according to Innovation News Network.
The significance doesn't require overclaiming to be real. This is a small, genuine, peer-reviewed advance in light-driven motion. It demonstrates a physical capability — simultaneous multi-axis control of a microscopic object by light alone — that hadn't been shown before. Whether it becomes the foundation for interstellar sails or remains an elegant laboratory demonstration is a question that depends on results not yet in.
What the Texas A&M team has built is a device that moves because the world pushes it, carrying nothing. That is a real thing. The distance from there to the stars is still very far.