Two-dimensional Dirac plasmon-polaritons in graphene,3D topological insulator and hybrid systems

Collective oscillations of massless particles in two-dimensional(2D)Dirac materials offer an innovative route toward implementing atomically thin devices based on low-energy quasiparticle interactions.Strong confinement of nearfield distribution on the 2D surface is essential to demonstrate extraordinary optoelectronic functions,providing means to shape the spectral response at the mid-infrared(IR)wavelength.Although the dynamic polarization from the linear response theory has successfully accounted for a range of experimental observations,a unified perspective was stll elusive,connecting the state-of-the-art developments based on the 2D Dirac plasmon-polaritons.Here,we review recent works on graphene and three-dimensional(3D)topological insulator(TI)plasmon-polariton,where the mid-IR and terahertz(THz)radiation experiences prominent confinement into a deep-subwavelength scale in a novel optoelectronic structure.After presenting general light-matter interactions between 2D Dirac plasmon and subwavelength quasiparticle excitations,we introduce various experimental techniques to couple the plasmonpolaritons with electromagnetic radiations.Electrical and optical controls over the plasmonic excitations reveal the hybridized plasmon modes in graphene and 3D Tl,demonstrating an intense near-field interaction of 2D Dirac plasmon within the highly-compressed volume.These findings can further be applied to invent optoelectronic biomolecular sensors,atomically thin photodetectors,and laser-driven light sources.