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Over the past decade, orbital angular momentum has garnered considerable interest in the field of plasmonics owing to the emergence of surface-confined vortices, known as plasmonic vortices. Significant progress has been made in the generation and manipulation of plasmonic vortices, which broadly unveil the natures of plasmonic spin–orbit coupling and provide accessible means for light–matter interactions. However, traditional characterizations in the frequency domain miss some detailed information on the plasmonic vortex evolution process. Herein, an exotic spin–orbit coupling phenomenon is demonstrated. More specifically, we theoretically investigated and experimentally verified a temporally deuterogenic vortex mode, which can be observed only in the time domain and interferes destructively in the intensity field. The spatiotemporal evolution of this concomitant vortex can be tailored with different designs and incident beams. This work extends the fundamental understanding of plasmonic spin–orbit coupling and provides a unique optical force manipulation strategy, which may fuel plasmonic research and applications in the near future.

On‐chip wavefront manipulation of terahertz surface plasmons is crucial for the miniaturization and practical application of terahertz technology. Recently, topological metasurfaces have emerged as a promising avenue for spin‐decoupled wavefront manipulation, leveraging the unique topological properties of non‐Hermitian matrices near their singular points. Despite their innovative phase control mechanisms, topological metasurfaces have not yet been explored for surface plasmon devices. Here, spin‐decoupled wavefront manipulation of terahertz surface plasmons is experimentally achieved using freestanding topological metasurfaces. This approach promises to expand the control methods of surface plasmons and broaden the application scenarios of topological metasurfaces, providing a new paradigm for the design of integrated on‐chip terahertz devices. [ABSTRACT FROM AUTHOR]

Metasurfaces have been continuously garnering attention in both scientific and industrial fields owing to their unprecedented wavefront manipulation capabilities using arranged subwavelength artificial structures. Terahertz vortex beams have become a focus of research in recent years due to their prominent role in many cutting-edge applications. However, traditional terahertz vortex beam plates are often faced with challenges including large size, low efficiency, and limited working bandwidth. Here, we propose and experimentally demonstrate highly efficient and broadband vortex beam plates based on metasurface in the terahertz region. The experimental results well verify that the designed metasurfaces can efficiently generate terahertz vortex beams with different orbital angular momentum topological charges in the range of 0.5–1 THz. Notably, the maximum efficiency can reach about 65% at 0.5 THz. The proposed devices may play a vital role in developing vortex beams-related terahertz applications. [ABSTRACT FROM AUTHOR]