Enhanced graphene surface plasmon polaritons for terahertz sources

Graphene surface plasmon polaritons (SPPs) have attracted extensive attention due to their unique properties, such as extreme light confinement and high tunability via doping and external electric fields, making them a promising platform for developing tunable terahertz sources. However, graphene SPPs suffer from a short lifetime and low radiation efficiency. Herein, we address these issues by replacing monolayer graphene with trilayer graphene and introducing a periodic nanostructure array into the middle graphene layer. Our results demonstrate that the lifetime of the SPPs has been enhanced from 0.22 to 0.44 ps when the monolayer graphene has been replaced by trilayer graphene. Additionally, we achieved a fourfold enhancement in radiation intensity by introducing a periodic nanostructure array into the middle graphene layer. Furthermore, we show that the resonant frequency can be tuned by adjusting the periodic nanostructure array. Our findings provide an effective approach for developing high-efficiency, tunable, and compact terahertz sources.