The local optical density of states is mapped with deep subwavelength resolution, and the results show evidence of topological edge states at the domain walls between topological and trivial lattices.

Topological photonic materials open new ways to route information for communication and computing purposes. Nanostructures with topological phases of light potentially allow lossless photon transport in large-scale optical integrated circuits. The paper examines two-dimensional photonic lattices operating in the visible spectral range.

To probe the optical properties of the photonic lattices modes, hyperspectral angle-resolved (energy-momentum) cathodoluminescence imaging was employed, which combines high-resolution spectral data with angular data. The measurements were performed with the SPARC cathodoluminescence detector.

The results of the paper demonstrate the feasibility to realize practical silicon-based topological geometries that are comparable with planar Si-based integrated optics technology, and to excite them locally with electron beams. If you would like to read the full paper, go here. To learn more about the possibilities of hyperspectral angle-resolved technique, register for the upcoming webinar.