Plasmonic enhanced nonlinear terahertz response in Dirac semimetal cadmium arsenide

The linear energy-momentum dispersion in the band structure has been identified as one of the key factors contributing to terahertz (THz) high harmonic generation (HHG) in single-layer graphene. As a three-dimensional analog, the Dirac semimetal Cd₃​As₂​ is also regarded as a promising candidate material exhibiting a large nonlinear susceptibility. In particular, the high mobility and relatively low carrier density of Cd₃As₂ offers an ideal platform to investigate plasmonic phenomena at THz frequencies. In this study, we create plasmonic arrays to enhance the nonlinear THz response in Cd₃As₂ ​as measured using high-field THz spectroscopy. We will present a comparative analysis between thin-films and plasmonic arrays of Cd₃As₂​ which provides insight into the underlying mechanisms of the nonlinear THz electrodynamics.