Generating broadband nondiffracting perfect vortex beams in the visible regime

Perfect vortex (PV) beams exhibiting topological charge-insensitive annular intensity distribution appear as a striking hotspot for significant advances in optical communication and quantum optics and have great potential to fulfill the requirements of futuristic optical communication systems. The recently developed planar photonics devices possessed an unprecedented ability for complex wavefront shaping at the micron scale; however, the limited working bandwidth and abruptly diverging light behavior of the current PV beam-generating planar photonics devices roadblock their applicability in practical systems. This work demonstrates a single-cell-driven broadband planar photonics platform to realize the nondiffracting-type PV beams for the visible spectrum. These PV beams exhibit long propagating constant-sized doughnuts for different topological charges and exhibit expected broadband response. The proposed concept is verified by numerically studying multiple meta-devices capable of generating nondiffracting-type PV beams. The presented photonics platform may bring considerable advances in real-life applications like machine vision. Graphical abstract: [Figure not available: see fulltext.].