The project will focus on optical properties emerging from interlayer interactions in 2D van der Waals materials by combining nanopatterning and electron microscopy analysis. Specifically, we will aim to realize hybrid polaritonic modes with nanoscale confinement and low losses for possible applications in light-based future information technology. Hybrid modes of plasmons and phonons in 2D heterostructures from single-crystalline silver or graphene with hexagonal boron nitride (hBN) will be tuned using cutting-edge nanopatterning with precise adjustment of both, the separate excitations and the coupling strength between them. Electron microscopy will provide complete dispersion relations and map out hybrid modes.
Experimental techniques comprise helium ion beam based nanopatterning, low-loss scanning transmission electron microscopy (STEM) electron energy-loss spectroscopy (EELS), confocal white-light spectroscopy and numerical techniques (FEM, BEM and return-time analysis) to complement experiments. The mode excitation and probing of electron-beam and optical excitation in a scanning near-field microscope will be compared.