Nanoscale electrodynamics offers a unique perspective for unraveling the complex physics underlying these phenomena. This talk is focused on our studies on the intricate relationships among topology, geometry, and electron correlations in systems with flat bands. I will first discuss the exploration of a 3D quasi-crystalline system, highlighting how photon momentum can lead to a novel Hall effect without magnetic field. Subsequently, the discussion shifts to introducing our latest development in optically coupled microwave impedance microscopy, and its ability to extract spectroscopic information on exciton excitations within transitional metal dichalcogenide (TMD) monolayers. Finally, I will share our recent exciton-assisted measurements on topological and correlated electronic states induced by flat bands in twisted TMD bilayers.