Terahertz metadevices for silicon plasmonics

Metamaterial devices (metadevices) have been developed in progress aiming to generate extraordinary performance over traditional devices in the (sub-)terahertz (THz) domain, and their planar integration with complementary-metal-oxide-semiconductor (CMOS) circuits pave a new way to build miniature silicon plasmonics that overcomes existing challenges in chip-to-chip communication. In an effort towards low-power, crosstalk-tolerance, and high-speed data link for future exascale data centers, this article reviews the recent progress on two metamaterials, namely, the spoof surface plasmon polaritons (SPPs), and the split-ring resonator (SRR), as well as their implementations in silicon, focusing primarily on their fundamental theories, design methods, and implementations for future THz communications. Owing to their respective dispersion characteristic at THz, these two metadevices are highly expected to play an important role in miniature integrated circuits and systems toward compact size, dense integration, and outstanding performance. A design example of a fully integrated sub-THz CMOS silicon plasmonic system integrating these two metadevices is provided to demonstrate a dual-channel crosstalk-tolerance and energy-efficient on-off keying (OOK) communication system. Future directions and potential applications for THz metadevices are discussed.