Numerical Study of Plasmonic Resonance Enhanced, Terahertz Second Harmonic Generation from Graphene in the Otto Configuration

We report on the plasmonic resonance-enhanced terahertz (THz) second-harmonic generation (SHG) from graphene via the technique of attenuated total reflection in the Otto configuration. Through our finite-difference time-domain numerical simulations, we reveal how greatly different parameters, including the radiation incidence angle, the graphene Fermi level, and the thickness and permittivity of the layer between the graphene and the prism, may affect the resonance condition, and so the intensity of generated second harmonic. Interestingly, we show how the great potential of graphene in the tunability of its Fermi energy provides the opportunity to preserve the plasmonic resonance condition and achieve the enhanced SHG upon variation of the fundamental-wave frequency without any need to employ the well-known approach of angular tuning of the illumination and detection facilities.