SSPP-Design Suppresses Horizontal Leaked Electrode Modes of Terahertz Photoconductive Antennas

Photoconductive antenna (PCA), which plays an essential role in a terahertz system, faces the challenge of low output power. The coplanar strip lines (CSLs) are fundamental components of a typical PCA. However, the horizontal leaked electrode modes, which are induced by the CSLs, directly impact the directivity of PCA and has not been resolved yet. Here, we propose a scheme that using spoof surface plasmon polariton (SSPP) to suppress the propagating horizontal electrode modes for enhancing directivity of PCA. For further improve the output performance of PCA, our microscale SSPP-design could combine with the well-realized nanoscale schemes which are based on enhancing the photoelectric conversion efficiency. Our design will be widely used in promising applications, such as THz detection, sensing and imaging.