Nontechnical Description Two-dimensional (2D) materials are atomically thin sheets with atoms strongly bonded within each layer but weakly bonded between layers. They have unique versatility as their electronic properties can be tuned by changing the composition of a layer or stacking different 2D sheets to form heterostructures. 2D materials have shown promise for emergent technologies such as photonics and quantum computing. This project focuses on dihalides, a class of 2D materials consisting of stacked layers of transition metal ions sandwiched between halogen atoms such as such as chlorine or iodine. The dihalides being studied in this project feature coherent oscillations of electric polarization called ferrons. These oscillations occur at terahertz frequencies, which are important for imaging, communications, and ultrafast electronics. Despite their technological potential, the properties of ferrons have received little experimental attention. One challenge with such studies is the small lateral dimensions of 2D materials, which can be smaller than the millimeter wavelength of light at terahertz frequencies. This project develops near-field techniques with resolution far beyond what is possible with conventional optical studies to investigate ferrons in dihalides. The results will enhance the understanding of ferroelectricity in 2D materials and inform the development of nanophotonics and quantum electronics. The project supports a workshop to provide training in scientific communication. Such skills are needed to present scientific results from emerging research to people from all backgrounds. The workshop enhances education of scientific communication, which is central to training the future workforce and ensure U.S. leadership in quantum science. Technical Description This project investigates how ferroelectric polarization oscillations influence the nanophotonic and optoelectronic properties of van der Waals dihalides. In this project, the princi