Optical vector vortex beams provide additional degrees of freedom for spatially distinguishable channels in data transmission. Although several coherent light sources carrying a topological singularity have been reported, it remains challenging to develop a general strategy for designing ultra-small, high-quality photonic nanocavities that generate and support optical vortex modes. Here we demonstrate wavelength-scale, low-threshold, vortex and anti-vortex nanolasers in a C5 symmetric optical cavity formed by a topological disclination. Various photonic disclination cavities are designed and analysed using the similarities between tight-binding models and optical simulations. Unique resonant modes are strongly confined in these cavities, which exhibit wavelength-scale mode volumes and retain topological charges in the disclination geometries. In the experiment, the optical vortices of the lasing modes are clearly identified by measuring polarization-resolved images, Stokes parameters and self-interference patterns. Demonstration of vortex nanolasers using our facile design procedure will pave the way towards next-generation optical communication systems.

more >> https://www.nature.com/articles/s41566-023-01338-2