Enhanced terahertz dual-band third-harmonic generation in graphene-assisted metamaterial

Nonlinear optics constitutes a pivotal component in scientific inquiry, with metamaterials emerging as a highly promising platform for advancing nonlinear optical phenomena. The present study introduces a metamaterial structure featuring dual -band surface plasmon polariton (SPP) resonances, aimed at enhancing third-harmonic generation within the terahertz frequency range. The metamaterial comprises graphene patches, a dielectric layer, and a metallic reflector, leveraging the enhanced local fields of SPP resonances to significantly boost thirdharmonic generation (THG) nonlinear processes. It exhibits two nearly identical peaks of third-harmonic generation conversion efficiency (CE) occur at 0.745 THz and 0.902 THz, enabling the structure ' s third-harmonic generation conversion efficiency reach 0.131 % at an incident power of 500 kW/cm 2 . And various data presented in this paper demonstrate the vast potential of the structure for combining nonlinear optics with metamaterials, promising broad prospects for applications in this field.