Researchers at Texas A&M University have demonstrated optical propulsion using laser-driven “metajets” with full three-dimensional control.

Their lab-scale results suggest that light-powered propulsion systems could cut travel time to Alpha Centauri, the closest star system to ours, to roughly 20 years.

Current space propulsion technologies would take hundreds of thousands of years to complete this journey, highlighting the immense potential of optical propulsion in driving future endeavours into the final frontier.

What is optical propulsion, and why is it gaining traction?

Optical propulsion uses light, typically from lasers, to generate force on objects without physical contact or onboard fuel. While the physics has been understood for decades, practical control has remained a barrier.

The latest work, led by Dr Shoufeng Lan, assistant professor and director of the Lab for Advanced Nanophotonics, provides a controlled demonstration of how light alone can direct motion in multiple dimensions.

Published in Newton, the study outlines a method to convert photon momentum into a measurable mechanical force.

The context is stark: conventional rocket propulsion would take hundreds of thousands of years to reach Alpha Centauri. Optical propulsion, by contrast, removes the need for fuel and instead relies on sustained external energy, potentially enabling far shorter journeys if scaled.

How do metajets work?

The system revolves around micron-scale devices called metajets, constructed from metasurfaces – ultrathin materials engineered with nanoscale patterns that dictate how light behaves when it hits them.

Several features define their operation:

• Momentum transfer: When light reflects off a surface, it imparts momentum. The metasurface structure channels that force in specific directions.
• Material-embedded control: Instead of adjusting the laser beam, control is built into the device itself through its geometry.
• Three-dimensional manoeuvrability: The metajets can move laterally, vertically, and rotate under laser illumination.
• Precision fabrication: Each nanoscale feature is designed in shape, orientation, and placement to achieve predictable motion.

Lan describes the effect as similar to ping pong balls bouncing off a surface. Each photon delivers a tiny push, but collectively they generate a controlled force.

The devices were fabricated at the AggieFab Nanofabrication Facility, supported by the Texas A&M Engineering Experiment Station, and tested in a fluid environment to compensate for gravity and enable clearer observation of motion.

What sets this apart from earlier optical propulsion research?

Previous optical propulsion experiments have typically been limited in control, often constrained to single-direction movement or dependent on carefully shaped light fields. The Texas A&M approach shifts that paradigm by embedding control within the material itself.

This distinction has practical implications. By decoupling control from the light source, the system allows more flexible force generation and simplifies the requirements on external laser systems.

It also introduces a generalisable framework grounded in fundamental physics rather than a narrow experimental setup.

Comparable work is underway at institutions such as California Institute of Technology, which is studying propulsion stability, and Rochester Institute of Technology, which is exploring diffractive grating platforms.

Lan’s team positions its contribution as a step toward unifying these efforts under a broader theoretical and experimental model.

Crucially, this is the first reported demonstration of full three-dimensional manoeuvrability using this class of optical system, according to the research team.

Could light-powered propulsion scale to spacecraft?

The current metajets are only tens of microns in size, which is smaller than the width of a human hair. That places the work firmly in the experimental domain. However, the underlying physics suggests scalability.

The force generated depends primarily on the power of the incoming light rather than the size of the object. In principle, increasing laser intensity could extend the same mechanics to larger systems, including spacecraft.

That concept underpins long-standing proposals for laser-driven sails and interstellar probes.

Significant engineering challenges remain:

• Delivering sustained, high-power laser energy over long distances
• Maintaining beam precision and stability across space
• Managing heat and material stress under continuous illumination
• Validating performance in microgravity conditions

The team is now seeking external funding to test the system in microgravity, where gravitational interference is minimised, and behaviour more closely reflects space conditions.

For now, the findings represent a controlled laboratory advance rather than a deployable propulsion system.

Still, they contribute to a growing body of research suggesting that light, not fuel, could eventually drive movement across vast distances, from microscopic devices to interstellar missions.