Monolayer Excitonic Emission for Imaging Spatial Dispersion of Photonic Crystals

Spatial dispersion of a photonic crystal manifests itself as an angle dependent optical response. Here, we use the emerging two-dimensional transition metal dichalcogenides (TMDCs) as a photon source to directly image the spatial dispersion in the reciprocal space. Excitonic emission from a monolayer MoS₂ is coupled to the delocalized Fano resonances supported by the photonic crystal slab, recreating isofrequency contours in the far-field. This integration of monolayer TMDCs and photonic crystal not only reveals the band structure of a photonic crystal but also provides a new route to controllable and directional excitonic light sources.