Near-field scanning microscopy of a silicon topological photonic metasurface using diamond color centers

Given the intricate relation between an object’s nanoscale geometry and its optical response, control over light-matter interactions in photonic structures largely rests on strategies able to map out the subwavelength structure of the electromagnetic modes a system can support. Here, we study the interaction between a small, room-temperature ensemble of nano-diamond hosted nitrogen-vacancy (NV) centers and the waveguide forming at the interface between topologically trivial and non-trivial photonic crystal lattices. We alternatively exploit color centers as sub-wavelength photon-sources or as near-field probes, a dual role that simultaneously allows us to characterize the spectral response of the waveguide, stimulate light propagation with preferential directionality, and sense the local chirality of the near field through the NV photoluminescence ellipticity.