Hyperbolic metasurfaces have recently emerged as a new research frontier because of the unprecedented capabilities to manipulate surface plasmon polaritons (SPPs) and many potential applications. However, thus far, the existence of hyperbolic metasurfaces has neither been observed nor predicted at low frequencies because noble metals cannot support SPPs at longer wavelengths. Here, we propose and experimentally demonstrate spoof plasmonic metasurfaces with a hyperbolic dispersion, where the spoof SPPs propagate on complementary H-shaped, perfectly conducting surfaces at low frequencies. Thus, non-divergent diffractions, negative refraction and dispersion-dependent spin-momentum locking are observed as the spoof SPPs travel over the hyperbolic spoof plasmonic metasurfaces (HSPMs). The HSPMs provide fundamental new platforms to explore the propagation and spin of spoof SPPs. They show great capabilities for designing advanced surface wave devices such as spatial multiplexers, focusing and imaging devices, planar hyperlenses, and dispersion-dependent directional couplers, at both microwave and terahertz frequencies.

双曲面超表面最近已成为一种新的研究前沿，因为它具有操纵表面等离激元极化子（SPPs）的空前能力和许多潜在的应用。然而，到目前为止，由于在稀有金属中不能支撑更长波长的SPP，因此在低频下还没有观察到或预测双曲面超表面的存在。在这里，我们提出并通过实验证明了具有双曲线弥散的欺骗性等离子体超表面，其中，欺骗性SPP在低频下在互补的H形，完美导电的表面上传播。因此，当欺骗性SPP在双曲线欺骗性等离子体超表面（HSPM）上移动时，观察到非发散衍射，负折射和色散相关的自旋动量锁定。HSPM提供了基础的新平台，以探索欺骗性SPP的传播和自旋。它们显示出在微波和太赫兹频率下设计高级表面波设备（例如空间多路复用器，聚焦和成像设备，平面超透镜以及依赖于色散的定向耦合器）的强大功能。