Multichannel terahertz quasi-perfect vortex beams generation enabled by multifunctional metasurfaces

Abstract Vortex beams carrying orbital angular momentum (OAM) open a new perspective in various terahertz research. Multichannel and divergence controllable vortex beam generation holds the key to promoting development of OAM related Here, we introduced experimentally demonstrated quasi-perfect (Q-PVB) with angle independent topological charge multichannel Q-PVBs all-dielectric multifunctional metasurfaces. By superimposing specific phase functions together into metasurfaces, multiple four-channel different charges are generated as well focused at separated positions. High resolution characterization electric field shows good quality broadband properties Q-PVBs. Interestingly, compared conventional perfect beam; Q-PVB displays smaller thinner ring width. The metasurfaces proposed here provide promising avenue realize compact systems; benefiting researches such mode division multiplexing, plasmonic enhancement spinning objective detection.