Terahertz field-driven photoemission via 3D-printed resonant nanocones

We exploit the strong field enhancement offered by vertical gold nanocones resonating at 1 THz to induce THz field-driven electron emission. The nanocones are fabricated via an advanced 3D printing technique on a photopolymer and are successively gold coated. We demonstrate the clear advantage offered by nanocones featuring a monopolar resonance at THz frequencies with respect to traditional non-resonant tips via numerical modelling, THz far-field characterization, and the analysis of electron-induced argon gas fluorescence. Finally, we show that a further degree of optimization is enabled by tailoring the collective response of the nanocones when arranged in an array geometry.