High-efficiency, broadband all-dielectric transmission metasurface for optical vortex generation

Orbital angular momentum (OAM) generated by metamaterials has interesting properties in many applications. But in near infrared communication wave bands, broadband OAM generators have rarely been investigated. Here, we report an approach to design a high efficiency, broadband all dielectric transmission metasurface working in a telecom wave band from 1300 nm to 1700 nm. Simulated OAM generators with a topological charge of m= 1 and m= 20 present good mode purity up to 99.99% and high energy efficiency up to 97.38%. The proposed broadband all-dielectric OAM generator is meaningful to reduce dispersion-induced strong distortions and exploit new applications such as broadband object detection and multiplexed communication.