Quasi-one-dimensional elastic and stretchable spoof surface plasmonic waveguide with zero Poisson's ratio [Invited]

Spoof surface plasmon polaritons (SSPPs) have demonstrated significant potential as low-loss surface waves for signal propagation at low frequencies. However, most existing two-dimensional metallic thin-film designs have not prioritized structural stretchability. To enhance SSPPs transmission stability under stretching deformation, we propose and experimentally demonstrate a quasi-one-dimensional (1D) elastic and stretchable spoof surface plasmonic waveguide (SSPW) featuring zero Poisson's ratio and elastic recovery capability. By integrating thermoplastic polyurethane (TPU) material with helix-inspired quasi-1D metallic architectures, the designed quasi-1D SSPW achieves stable signal transmission with high efficiency and strong electromagnetic energy confinement under substantial stretching. Meanwhile, the quasi-1D SSPW exhibits strong robustness and excellent stability, undergoing complex deformations, i.e., bending, twisting, and stretching. The proposed quasi-1D elastic and stretchable SSPP platform provides a promising foundation for the development of flexible, reconfigurable plasmonic circuits and integrated systems.