▎ 摘　　要

As one emerging plasmonic material, graphene can support surface plasmons at infrared and terahertz frequencies with unprecedented properties due to the strong interactions between graphene and low-frequency photons. Since graphene surface plasmons exist in the infrared and terahertz regime, they can be thermally pumped (excited) by the infrared evanescent waves emitted from an object. Here we show that thermal graphene plasmons can be efficiently excited and have monochromatic and tunable spectra, thus paving a way to harness thermal energy for graphene plasmonic devices. We further demonstrate that "thermal information communication" via graphene surface plasmons can be potentially realized by effectively harnessing thermal energy from various heat sources, e.g., the waste heat dissipated from nanoelectronic devices. These findings open up an avenue of thermal plasmonics based on graphene for different applications ranging from infrared emission control, to information processing and communication, to energy harvesting.