Spatially Controlled Optical Vortex Generation Using Low-Loss Antimony Telluride Metasurfaces

Optical vortex beams, endowed with orbital angular momentum (OAM) due to their helical wavefronts, are essential for advancements in optical manipulation, quantum computing, and communication technologies. Existing methods for generating vortex beams often struggle with issues such as low efficiency, limited scalability, and rigid control over beam properties. To address these limitations, we have developed a novel vortex beam generator utilizing a plasmonic metasurface constructed from the antimony telluride (Sb₂Te₃). Distinct from traditional plasmonic materials, Sb₂Te₃ offers significantly lower optical losses in the visible spectrum, enhancing both efficiency and beam quality. By integrating the Pancharatnam–Berry phase mechanism with Sb₂Te₃'s low-loss characteristics, the approach facilitates unprecedented control over the beam's propagation trajectory and OAM mode. This design allows not only customizable beam trajectories but also manipulation of OAM for controlled topological charge evolution, which is beneficial for scalable and integrated photonic systems. The demonstrated vortex beam, using Sb₂Te₃, paves the way for more compact, efficient vortex beam generation, broadening their potential applications in photonic technologies.