Generating arrays of perfect vector vortex beam with six on-demand degrees of freedom in metasurfaces

Abstract

Perfect vector vortex beams (PVVBs) possess various degrees of freedom (DoFs) for optical information applications, benefiting from increasing information capacity, processing speed, etc. During the last two decades, various methods have been proposed for generating and controlling PVVBs, but most of these methods can only manipulate two or three DoFs, greatly hindering further exploration and application of PVVBs. To overcome this problem, we propose an attenuation-controlled holographic technique based on metasurfaces, which can realize the arbitrary and independent control of 6-DoFs, greatly improving the manipulation dimension of PVVBs. The PVVBs with 6 on-demand DoFs can appear in the array forms of either concentric or matrix rings without cross-talks or number limitations, which notably enlarges the number of information channels that can be simultaneously employed. Furthermore, we introduce a multi-dimensional dynamic addressing strategy for optical encryption with the advantages of both large capacity and high security due to its theoretically infinite code space. Our findings can not only deepen the study of optical field manipulation at the nanoscale, but also expand the application of structural light, promoting their utilization across the fields of nanophotonics, integrated optics, and optical information science at the high-dimensional level.