Nonlinear Interaction of Terahertz Light with Two-Dimensional Nanomaterials

Two-dimensional (2D) nanomaterials such as graphene and transition metal dichalcogenides (TMDs), hold great promise for the engineering of modern nanophotonic devices that will operate at terahertz (THz) speed rates, with reduced energy requirements. Particularly, their nonlinear properties at THz frequencies, are expected to be the key element for the development of THz nanodevices that can generate new frequencies, control light propagation or act as nonlinear optical modulators. The TeraNanoLIGHT project aims to study with nanometer spatial and femtosecond temporal resolution, the ultrafast interaction of 2D nanomaterials with atomically strong (multi-MV/cm) THz fields, promoting the light-matter interactions into the non-perturbative regime. Intense THz transients will be combined with a scattering-type scanning near-field optical microscope (SNOM) to achieve atomically strong fields. Initially, THz surface plasmons (SPs) will be resonantly coupled in graphene, and their nonlinear behavior will be studied by monitoring their formation, propagation and temporal evolution as the THz field strength increases into the nonlinear regime. Furthermore, non-resonant nonlinearities will be explored, exploiting the oscillating THz field as an ultrafast AC bias. The possibility to observe high harmonic generation (HHG) with characteristics similar to those of atomic gases, will be studied in monolayer TMDs and heterostructures of different layers number and twist angles, excited by an out-of-plane polarized THz field. Finally, the opportunity of exploiting the extremely nonlinear interaction of light with matter, to improve the spatial resolution of SNOM, will be investigated. TeraNanoLIGHT project, envisions to facilitate our understanding about the ultrafast interaction of intense THz light with 2D materials and their high-order nonlinearities. This understanding is expected to trigger innovative research on the development of the future THz lightwave electronic devices.