Synchrotron terahertz nanospectroscopy: experimental development and application in nanostructured materials

Abstract

Several recent questions related to local properties of two-dimensional (2D) materials are found in the frequency range of a few terahertz (THz). Among these issues is the possibility of the existence of polariton waves in 2Ds based on Transition Metal Dichalcogenides (TMDs), coexisting with phonon activity in the THz range in these materials. Such waves have not yet been experimentally confirmed since there is no experiment capable of performing THz spectroscopy with a spatial resolution of a few tens of nanometers. This PhD project work plan, which is linked to the FAPESP 2019/14017-9 Young Researcher project, includes the development of pioneering instrumentation for performing nanoscopy and nanospectroscopy at wavelengths of up to 100 ¼m. Exploring the concept of Scanning Near-Field Optical Scattering Microscopy (s-SNOM), the project will use IR and THz radiation from the new IMBUIA station on Sirius and explore an alternative interferometric arrangement for s-SNOM and predict a gain in sensitivity up to 6 times compared to current experiments, in addition to extending the spectral range to THz. This experimental physics and instrumentation project aims at training a researcher in this important modality of ultramicroscopy. The project has the potential to place Brazil at the forefront of the topic, given that the extreme spectral range for nanospectroscopy at long wavelengths is lambda=30 ¼m. (AU)