Stretchable carbon nanotube metasurfaces enable terahertz wavefront control

Jun 08, 2026

Researchers show stretchable SWCNT metasurfaces that tune terahertz wavefronts, focal length, and beam steering through mechanical strain.

(Nanowerk News) Researchers led by Professor Yan Zhang of Capital Normal University have demonstrated terahertz wavefront control using stretchable metasurfaces made from single-walled carbon nanotube film on silicone. The work, published in Light: Advanced Manufacturing (“Dynamic terahertz wavefront control using stretchable single-walled carbon nanotube-based metasurfaces”), shows how mechanical strain can tune terahertz beam focusing and steering after a device has been fabricated.

Key Findings

Terahertz waves sit between microwaves and infrared light. They are relevant to wireless communication, security imaging, and non-destructive sensing, but practical systems need compact components that can redirect or refocus beams during operation. Metasurfaces address part of this problem by using ultrathin arrays of subwavelength resonators to control electromagnetic waves. Most such structures, however, have fixed optical responses once made. The new devices replace rigid metallic patterns with single-walled carbon nanotube, or SWCNT, films on a stretchable silicone substrate. The material choice matters because terahertz components that rely on metal patterns can lose performance when strained. By using conductive nanotube films that can tolerate deformation, the researchers designed metasurfaces whose optical behavior changes when the substrate is stretched. Schematic of the SWCNT-based stretchable metasurface for THz wavefront manipulation. (Image: Reproduced from DOI:10.37188/lam.2026.066, CC BY) The researchers described the design principle and device geometry in the paper: “Unlike conventional plasmonic metasurfaces, which rely on metallic patterns that are prone to cracking under strain, our SWCNT-based design leverages the intrinsic elasticity and high electrical conductivity of the nanotubes to maintain optical functionality over repeated deformation cycles. We designed and experimentally demonstrated two functional SWCNT-based metasurfaces. Each metasurface device has an area of 21 mm × 21 mm and consists of 60 × 60 rectangular rods of SWCNT film with different orientations, supported by a silicone substrate. ” One prototype acts as a focal-length-tunable metasurface lens. When a 0.35 THz left-handed circularly polarized wave passes through the device, the right-handed circularly polarized component focuses 19.4 mm from the lens. Applying uniform mechanical stretching moves the focal point backward as strain increases, which increases the focal length without changing the fabricated pattern. The article’s multimedia includes a schematic of the SWCNT-based stretchable metasurface used for terahertz wavefront manipulation. It also includes an image of the focal-length-tunable SWCNT metasurface lens. The paper’s Figure 2 presents photographs of the fabricated lens and stretching fixture, together with experimentally measured changes in the optical field during stretching. The second prototype is an off-axis metasurface lens for dynamic beam steering. Stretching this device moves the focus along the optical axis while also changing the lateral beam direction. In the unstretched state, experimental measurements placed the focal point at z = 19.9 mm, with a beam deflection angle of -19.69°. When the stretching factor A increased to 1.2, the focus shifted to 27.7 mm. Over the same deformation, the beam deflection angle changed from -19.69° to -16.01°, a relative shift of 3.68°. The researchers reported that these measurements validate mechanically tunable beam steering for terahertz waves. The multimedia also includes a dynamic beam steering demonstration with the off-axis metasurface lens, and Figure 3 presents photographs and optical field measurements for that device. “The presented technique opens a new avenue for smart, lightweight, and wearable THz components,” the researchers forecast. “We envision this platform evolving into fully programmable and adaptive photonic systems, where THz beams can be manipulated as effortlessly as one stretches a rubber sheet. Such capabilities will be instrumental for future 6G wireless networks, real-time security screening, and intelligent human-device interactive interfaces.” The demonstrations show that stretchable carbon nanotube metasurfaces can provide post-fabrication control over terahertz optical fields. Rather than relying on rigid structures with fixed responses, the devices use controlled deformation of a nanotube-on-silicone platform to tune focal length and steering angle, pointing to adaptive terahertz components based on materials that remain functional under strain.