In our team we investigate atomic-scale optical properties of molecules and low dimensional materials. In recent years, experimental development in scanning tunneling microscopy opened the possibility to study the interaction of light with nanoscale samples in the precisely controlled environment of the tunneling junction of the microscope. We are interested in theoretical modelling of light-matter interactions pushed to the limit where light is concentrated down to the scale of a few atoms. We investigate how in this extreme situation the rules governing light-matter interaction must be fundamentally redefined and how this new regime can be used to study and control optical excitations and their dynamics in molecules, molecular aggregates, graphene-based structures, but also the family of 2D semiconductors including the transition metal dichalcogenides and defects therein. Particularly these promising emergent materials and nanostructures formed by their combination into heterostructures open the possibility to taylor material’s optical properties on the nanoscale and design e.g. efficient non-classical photon sources or optical sensors.