Researchers at Texas A&M University have demonstrated a method to move microscopic objects in three dimensions using only laser light, a step toward potential laser-propelled spacecraft for interstellar travel.
The team, led by assistant professor Shoufeng Lan, built micron-scale devices called “metajets” from engineered metasurfaces that redirect light to generate thrust without physical contact. In lab tests, these devices moved laterally and vertically when illuminated, achieving what the researchers describe as the first demonstration of full three-dimensional maneuverability in optical propulsion.
The approach differs from earlier light-based propulsion concepts, such as solar sails or the Breakthrough Starshot initiative, by embedding control directly into the material’s structure rather than shaping the incoming laser beam. This design allows for more flexible force generation and, according to the researchers, better scalability to larger objects given sufficient laser power.
The metajets, each smaller than the width of a human hair, were fabricated at the Texas A&M AggieFab Nanofabrication Facility and tested in a fluid environment to counteract gravity. By adjusting nanoscale silicon pillars on a silica base, the team tuned the devices to refract light at a wavelength of one micrometer, enabling precise control over the direction and magnitude of the resulting force.
Lan compared the mechanism to ping pong balls bouncing off a surface: whereas individual photon momentum transfers are tiny, in the frictionless environment of space, cumulative effects could turn into significant over time. The researchers note that scaling the concept to interstellar scales would require substantial advances in laser power and spacecraft design, but the principle of light-driven motion has now been demonstrated in three dimensions for the first time.
While the current work remains a laboratory-scale proof of concept, it addresses a longstanding challenge in photonic propulsion: achieving complex maneuverability without mechanical parts or external tethers. Earlier experiments, including those by the European Space Agency on graphene aerogels, have explored laser steering but lacked the three-dimensional control demonstrated here.
The research was published in the journal Newton and builds on years of theoretical work in metamaterials, and photonics. Though still far from enabling a 20-year journey to Alpha Centauri, the team says the scalable nature of the design keeps the concept viable for future development.
How does this method differ from solar sails or laser-powered lightsails?
Unlike solar sails, which rely on reflecting sunlight, or lightsail concepts that shape the incoming laser beam to control motion, the metajet approach builds directional control into the material itself via nanoscale patterning, allowing more flexible force generation.
What is the main limitation preventing immediate use for interstellar travel?
The demonstrated devices are microscopic and require vastly more laser power to scale to spacecraft size; the technology remains a proof of concept with significant engineering hurdles before practical application.
