Fig. 1: Topological Dirac-vortex microcavity lasers on silicon.

a Conceptual illustration of a topological Dirac-vortex microcavity laser fabricated on a silicon substrate. The photonic crystal structure was defined in the active layer and suspended by partially removing the sacrificial layer. The III–V buffer and defect-filter layers were carefully optimized to minimize the effects of lattice mismatch between the III–V materials and silicon substrate. b Tilted-view scanning electron microscope image of the fabricated topological Dirac-vortex photonic crystal cavity. Scale bar, 500 nm. c Cross-sectional bright-field transmission electron microscope image of the active layer containing four-stack InAs/InGaAs QD layers. Scale bar, 100 nm. Adapted with permission from Ref. 34. © 2022 American Chemical Society