All-plasmonic sub-terahertz wireless communication link.

A promising approach to increase wireless capacity is the transition to sub-Terahertz carrier frequencies (0.1-0.3 THz). While traditional high-frequency approaches employ III-V semiconductor technologies, plasmonics is emerging as a potential solution for highest-speed components. In this paper, we introduce an all-plasmonic sub-THz wireless link, utilizing compact (<50 µm²) plasmonic components that exhibit a flat frequency response up to 300 GHz while providing full flexibility in carrier frequency selection. The plasmonic approach offers unprecedented integration potential, compatibility with diverse platforms, and scalable, cost-effective fabrication. To demonstrate its capabilities, we conduct a lab experiment transmitting 120 Gbit/s on a 285 GHz carrier across a 5 m free-space link, validating the system's linear performance and large power dynamic range. While this first demonstration is constrained in transmission distance, it showcases the transformative potential of plasmonic technology in closing the wireless-optical data-rate bottleneck: The proposed plasmonic converters could provide the capacity expansion needed for future 5G, 6G, and beyond wireless networks, paving the way for high-speed, cost-effective, and scalable sub-THz communications.