2026-04-27 テキサスA&M大学
Researchers at Texas A&M University have successfully used lasers to precisely steer tiny devices known as “metajets” in three dimensions — a breakthrough in optical propulsion that could one day help power interstellar travel without traditional fuel.Credit: Getty Images
＜関連情報＞
- https://stories.tamu.edu/news/2026/04/27/light-powered-propulsion-expands-space-exploration-possibilities/
- https://www.cell.com/newton/fulltext/S2950-6360(26)00073-3
メタジェットの光推進と浮上 Optical propulsion and levitation of metajets
Kaushik Kudtarkar ∙ Yixin Chen ∙ Ziqiang Cai ∙ … ∙ Zi Jing Wong ∙ Yongmin Liu ∙ Shoufeng Lan
Newton Published:March 30, 2026
DOI:https://doi.org/10.1016/j.newton.2026.100471
Accessible overview
Metasurfaces are ultrathin and artificial materials that have revolutionized many fields, including optics and photonics, by engineering constituent structures. This structural engineering has been widely studied to tailor all aspects of light, such as amplitude, phase, frequency, and polarization. In a reverse manner, their mechanical responses due to the control of light, particularly in momentum change associated with anomalous deflection, are less explored. From Newton’s law of motion, any momentum change between the input and output light at an interface can generate a compensating mechanical reaction force on the interface itself. Despite its fundamental nature, a general relationship between anomalous deflection and the resulting optical force has been missing. Building on generalized Snell’s law and momentum conservation, we develop a theoretical framework that connects the momentum change induced by metasurfaces with force generation. The generated forces are not only lateral but also vertical, enabling full three-dimensional (3D) optical control. We term these controllable forces metaphotonic forces, since they arise directly from engineered momentum transfer from the metasurface. To experimentally demonstrate this concept, we fabricate micron-scale metajets composed of silicon nanopillar arrays designed to impose a distributed phase gradient. When illuminated by a normally incident beam, these free-standing devices simultaneously translate laterally and lift vertically, enabling 3D motion not accessible with conventional optical manipulation methods. Our experimental measurements confirm the predicted dependence of propulsion and levitation on metasurface design parameters, including refraction efficiency, refraction angle, and phase gradient ratio. Importantly, the metaphotonic forces scale with optical power and are not fundamentally constrained by device size, suggesting opportunities to extend this approach from microscale applications, such as microrobots, to large settings, including interstellar light sails for space travel.
Highlights
- Shaping light’s wavevector for precise control over the force exerted on metajets
- Theoretical framework of force generation in metasurfaces validated by experiments
- Both anomalous refraction and reflection can generate 3D force for manipulation
- Force is scalable with increased light power for applications like light sails
Summary
The quintessential hallmark distinguishing metasurfaces from traditional optical components is engineering materials and structures to manipulate light at will. Enabling this engineering freedom, in a reverse manner, to control the motion of objects constituted by metasurfaces could extend our capability of optical manipulation at different scales. Here, we introduce generalized optical manipulation by recapitulating metasurfaces as engineered interfaces with anomalous reflection and refraction. Upon combining Newton’s law of motion and generalized Snell’s law, we find that three-dimensional motions would be possible by inducing an extra wavevector component. As an example, we achieve this condition through a spatially distributed phase gradient using purposely arranged silicon nanopillars. Our experiments and simulations simultaneously reveal an in-plane propulsion and out-of-plane levitation of metasurfaces not seen in other optical manipulations. The optical force scales with incident power and is not fundamentally dependent on the size of the metajet, suggesting opportunities to scale this concept toward large-area applications such as interstellar light sails.
