Photonic Disclination Nanolaser with a High Topological Charge of 2

Photonic topological insulators that exploit topological defects of disclinations provide a robust solution for light manipulation to form compact optical vortices and on-chip integration with reduced scattering loss and energy consumption. However, vortex beams with high topological charges are required to improve the robustness and capacity of data transmission systems. In this work, we demonstrate a wavelength-scale nanolaser with a topological charge greater than 1 in a C6 symmetric photonic disclination cavity. A vortex mode with a topological charge of 2 was solely excited in the photonic disclination cavity designed using the correspondence between the tight-binding model and optical simulation, exhibiting a high-quality factor and small mode volume. In the experiment, the vortex lasing mode and its topological charge were verified using systematic measurements of lasing properties and polarization-resolved mode images. This work paves the way for the application of advanced nanophotonic devices in laser technology and high-precision optical communications.