Unidirectional surface magnetoplasmon-driven metasurfaces for manipulating terahertz waves

Terahertz (THz) technologies have garnered significant attention in recent years due to their promising applications in future communication and sensing systems. Metasurfaces, which are two-dimensional metamaterials composed of engineered meta-atoms, offer precise control over local phase at subwavelength scales, providing a versatile platform for designing ultra-compact, high-performance THz components. However, the integration of existing THz metasurfaces on-chip remains challenging, as they typically require external light sources for excitation. In this work, we introduce a novel, to the best of our knowledge, class of metasurfaces that are driven by THz unidirectional guided waves, enabling arbitrary wavefront manipulation based on the unique dispersion properties of these guided waves. We numerically validate this approach through the design of two THz meta-devices using metal-air-semiconductor unidirectional surface magnetoplasmons, which efficiently convert unidirectional guided modes into wavefronts of 2D and 3D focused waves. This new class of THz metasurfaces, with its ease of on-chip integration, opens exciting new possibilities for THz sensing, imaging, and networking applications.